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Bonsignore G, Martinotti S, Ranzato E. Wound Repair and Ca 2+ Signalling Interplay: The Role of Ca 2+ Channels in Skin. Cells 2024; 13:491. [PMID: 38534335 DOI: 10.3390/cells13060491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/02/2024] [Accepted: 03/08/2024] [Indexed: 03/28/2024] Open
Abstract
The process of wound healing is intricate and tightly controlled, involving a number of different cellular and molecular processes. Numerous cellular functions, especially those related to wound healing, depend critically on calcium ions (Ca2+). Ca2+ channels are proteins involved in signal transduction and communication inside cells that allow calcium ions to pass through cell membranes. Key Ca2+ channel types involved in wound repair are described in this review.
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Affiliation(s)
- Gregorio Bonsignore
- Dipartimento di Scienze e Innovazione Tecnologica (DiSIT), University of Piemonte Orientale, 15121 Alessandria, Italy
| | - Simona Martinotti
- Dipartimento di Scienze e Innovazione Tecnologica (DiSIT), University of Piemonte Orientale, 15121 Alessandria, Italy
- SSD Laboratori di Ricerca-DAIRI, Azienda Ospedaliero-Universitaria SS. Antonio e Biagio e Cesare Arrigo, 15121 Alessandria, Italy
| | - Elia Ranzato
- Dipartimento di Scienze e Innovazione Tecnologica (DiSIT), University of Piemonte Orientale, 15121 Alessandria, Italy
- SSD Laboratori di Ricerca-DAIRI, Azienda Ospedaliero-Universitaria SS. Antonio e Biagio e Cesare Arrigo, 15121 Alessandria, Italy
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Eickhoff S, Franzen L, Korda A, Rogg H, Trulley VN, Borgwardt S, Avram M. The Basal Forebrain Cholinergic Nuclei and Their Relevance to Schizophrenia and Other Psychotic Disorders. Front Psychiatry 2022; 13:909961. [PMID: 35873225 PMCID: PMC9299093 DOI: 10.3389/fpsyt.2022.909961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/14/2022] [Indexed: 11/29/2022] Open
Abstract
The basal forebrain cholinergic nuclei (BFCN) provide the main cholinergic input to prefrontal cortices, the hippocampi, and amygdala. These structures are highly relevant for the regulation and maintenance of many cognitive functions, such as attention and memory. In vivo neuroimaging studies reported alterations of the cholinergic system in psychotic disorders. Particularly, a downregulation of nicotinic and muscarinic acetylcholine receptors has been found. Crucially, such alterations in neurotransmission have been associated with cognitive impairments and positive and negative symptoms. Recent pharmacological studies support these findings, as they demonstrated an association between the manipulation of cholinergic transmission and an attenuation in symptom severity. Targeting acetylcholine receptors has therefore become a focus for the development of novel psychopharmacological drugs. However, many open questions remain. For instance, it remains elusive what causes such alterations in neurotransmission. While evidence supports the idea that BFCN structural integrity is altered in schizophrenia, it remains to be determined whether this is also present in other psychotic disorders. Furthermore, it is unclear when throughout the course of the disorder these alterations make their appearance and whether they reflect changes in the BFCN alone or rather aberrant interactions between the BFCN and other brain areas. In this review, the specific role of the BFCN and their projections are discussed from a neuroimaging perspective and with a focus on psychotic disorders alongside future directions. These directions set the stage for the development of new treatment targets for psychotic disorders.
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Affiliation(s)
- Sofia Eickhoff
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, Germany
| | - Leon Franzen
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, Germany
| | - Alexandra Korda
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, Germany
| | - Helena Rogg
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, Germany
| | - Valerie-Noelle Trulley
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, Germany
| | - Stefan Borgwardt
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, Germany
| | - Mihai Avram
- Translational Psychiatry, Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, Germany
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El Makawy AI, Mabrouk DM, Ibrahim FM, Ahmed KA. Genotoxic, biochemical and histopathological studies to assessment the topiramate hepatorenal toxicity in mice. Drug Chem Toxicol 2019; 45:103-112. [DOI: 10.1080/01480545.2019.1660364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
| | | | - Faten M. Ibrahim
- Medicinal and Aromatic Plants Research Department, National Research Centre, Giza, Egypt
| | - Kawkab A. Ahmed
- Pathology Department, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
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Connolly C, Madden SF, Buggy DJ, Gallagher HC. Expression of anaesthetic and analgesic drug target genes in excised breast tumour tissue: Association with clinical disease recurrence or metastasis. PLoS One 2017; 12:e0177105. [PMID: 28558008 PMCID: PMC5448742 DOI: 10.1371/journal.pone.0177105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 04/21/2017] [Indexed: 11/18/2022] Open
Abstract
Background Retrospective analyses suggest anaesthetic-analgesics technique during cancer surgery may affect recurrence/metastasis. This could involve direct effects of anaesthetic-analgesic drugs on cancer cells. While μ-opioid receptor over-expression in lung tumours is associated with greater metastasis, other anaesthetic-analgesic receptor targets in cancer recurrence/metastasis remain unexplored. Therefore, we evaluated the association between genetic expression of anaesthetic-analgesic receptor targets and recurrence/metastasis, using a repository of breast cancer gene expression and matching clinical data. Methods A list of 23 genes encoding for the most prominent anaesthetic-analgesic receptor targets was compiled. This was processed through BreastMark- an algorithm integrating gene expression data from ~17,000 samples and clinical data from >4,500 breast cancer samples. Gene expression data was dichotomized using disease-free survival (survival without recurrence) and distant disease-free survival (survival without metastasis) as end points. Hazard ratios were calculated by Cox-regression analysis. Enrichment for prognostic markers was determined by randomly choosing 23-member gene lists from all available genes, calculating how often >5 significant markers were observed and adjusting p-values for multiple testing. This was repeated 10,000 times and an empirical p-value calculated. Results Of 23 selected genes, 9 were significantly associated with altered rates of metastasis and 4 with recurrence on univariate analysis. Adjusting for multiple testing, 5 of these 9 genes remained significantly associated with metastasis, non with recurrence. This ratio of genes (5/23) was not significantly enriched for markers of metastasis (p = 0.07). Conclusion Several anaesthetic-analgesic receptor genes were associated with metastatic spread in breast cancer. Overall there was no significant enrichment in prognostic markers of metastasis, although a trend was observed.
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Affiliation(s)
- C. Connolly
- Dept. of Anaesthesia, Mater Misericordiae University Hospital, Dublin, Ireland
- School of Medicine, University College Dublin, Dublin, Ireland
- * E-mail: (CC); (DJB)
| | - S. F. Madden
- RCSI Population Health Sciences, Dept. of Psychology, Royal College of Surgeons, Dublin, Ireland
| | - D. J. Buggy
- Dept. of Anaesthesia, Mater Misericordiae University Hospital, Dublin, Ireland
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
- Outcomes Research Consortium, Cleveland Clinic, Cleveland, Ohio, United States of America
- * E-mail: (CC); (DJB)
| | - H. C. Gallagher
- Dept. of Anaesthesia, Mater Misericordiae University Hospital, Dublin, Ireland
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
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Aoun J, Hayashi M, Sheikh IA, Sarkar P, Saha T, Ghosh P, Bhowmick R, Ghosh D, Chatterjee T, Chakrabarti P, Chakrabarti MK, Hoque KM. Anoctamin 6 Contributes to Cl- Secretion in Accessory Cholera Enterotoxin (Ace)-stimulated Diarrhea: AN ESSENTIAL ROLE FOR PHOSPHATIDYLINOSITOL 4,5-BISPHOSPHATE (PIP2) SIGNALING IN CHOLERA. J Biol Chem 2016; 291:26816-26836. [PMID: 27799301 PMCID: PMC5207189 DOI: 10.1074/jbc.m116.719823] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 10/26/2016] [Indexed: 11/06/2022] Open
Abstract
Accessory cholera enterotoxin (Ace) of Vibrio cholerae has been shown to contribute to diarrhea. However, the signaling mechanism and specific type of Cl- channel activated by Ace are still unknown. We have shown here that the recombinant Ace protein induced ICl of apical plasma membrane, which was inhibited by classical CaCC blockers. Surprisingly, an Ace-elicited rise of current was neither affected by ANO1 (TMEM16A)-specific inhibitor T16A(inh)-AO1(TAO1) nor by the cystic fibrosis transmembrane conductance regulator (CFTR) blocker, CFTR inh-172. Ace stimulated whole-cell current in Caco-2 cells. However, the apical ICl was attenuated by knockdown of ANO6 (TMEM16F). This impaired phenotype was restored by re-expression of ANO6 in Caco-2 cells. Whole-cell patch clamp recordings of ANO currents in HEK293 cells transiently expressing mouse ANO1-mCherry or ANO6-GFP confirmed that Ace induced Cl- secretion. Application of Ace produced ANO6 but not the ANO1 currents. Ace was not able to induce a [Ca2+]i rise in Caco-2 cells, but cellular abundance of phosphatidylinositol 4,5-bisphosphate (PIP2) increased. Identification of the PIP2-binding motif at the N-terminal sequence among human and mouse ANO6 variants along with binding of PIP2 directly to ANO6 in HEK293 cells indicate likely PIP2 regulation of ANO6. The biophysical and pharmacological properties of Ace stimulated Cl- current along with intestinal fluid accumulation, and binding of PIP2 to the proximal KR motif of channel proteins, whose mutagenesis correlates with altered binding of PIP2, is comparable with ANO6 stimulation. We conclude that ANO6 is predominantly expressed in intestinal epithelia, where it contributes secretory diarrhea by Ace stimulation in a calcium-independent mechanism of RhoA-ROCK-PIP2 signaling.
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Affiliation(s)
- Joydeep Aoun
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Mikio Hayashi
- the Department of Physiology, Kansai Medical University, 5-1, Shimmachi 2, Hirakata, 573 1010 Osaka, Japan
| | - Irshad Ali Sheikh
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Paramita Sarkar
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Tultul Saha
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Priyanka Ghosh
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Rajsekhar Bhowmick
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Dipanjan Ghosh
- the Department of Biotechnology, College of Science and Technology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, India, and
| | - Tanaya Chatterjee
- the Department of Biochemistry, Bose Institute, P-1/12 CIT Road, Scheme-VIIM, Kolkata 700054, India
| | - Pinak Chakrabarti
- the Department of Biochemistry, Bose Institute, P-1/12 CIT Road, Scheme-VIIM, Kolkata 700054, India
| | - Manoj K Chakrabarti
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Kazi Mirajul Hoque
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India,
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Fluorescent protein-scorpion toxin chimera is a convenient molecular tool for studies of potassium channels. Sci Rep 2016; 6:33314. [PMID: 27650866 PMCID: PMC5030662 DOI: 10.1038/srep33314] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 08/24/2016] [Indexed: 12/20/2022] Open
Abstract
Ion channels play a central role in a host of physiological and pathological processes and are the second largest target for existing drugs. There is an increasing need for reliable tools to detect and visualize particular ion channels, but existing solutions suffer from a number of limitations such as high price, poor specificity, and complicated protocols. As an alternative, we produced recombinant chimeric constructs (FP-Tx) consisting of fluorescent proteins (FP) fused with potassium channel toxins from scorpion venom (Tx). In particular, we used two FP, eGFP and TagRFP, and two Tx, OSK1 and AgTx2, to create eGFP-OSK1 and RFP-AgTx2. We show that these chimeras largely retain the high affinity of natural toxins and display selectivity to particular ion channel subtypes. FP-Tx are displaced by other potassium channel blockers and can be used as an imaging tool in ion channel ligand screening setups. We believe FP-Tx chimeras represent a new efficient molecular tool for neurobiology.
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Abstract
GABA and glycine are major inhibitory neurotransmitters in the CNS and act on receptors coupled to chloride channels. During early developmental periods, both GABA and glycine depolarize membrane potentials due to the relatively high intracellular Cl(-) concentration. Therefore, they can act as excitatory neurotransmitters. GABA and glycine are involved in spontaneous neural network activities in the immature CNS such as giant depolarizing potentials (GDPs) in neonatal hippocampal neurons, which are generated by the synchronous activity of GABAergic interneurons and glutamatergic principal neurons. GDPs and GDP-like activities in the developing brains are thought to be important for the activity-dependent functiogenesis through Ca(2+) influx and/or other intracellular signaling pathways activated by depolarization or stimulation of metabotropic receptors. However, if GABA and glycine do not shift from excitatory to inhibitory neurotransmitters at the birth and in maturation, it may result in neural disorders including autism spectrum disorders.
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Affiliation(s)
- Susumu Ito
- High-Tech Research Centre, Kokushikan University, Tokyo, Japan.
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Calvo DJ, Beltrán González AN. Dynamic Regulation of the GABAA Receptor Function by Redox Mechanisms. Mol Pharmacol 2016; 90:326-33. [PMID: 27439531 DOI: 10.1124/mol.116.105205] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 07/14/2016] [Indexed: 12/20/2022] Open
Abstract
Oxidizing and reducing agents, which are currently involved in cell metabolism and signaling pathways, can regulate fast inhibitory neurotransmission mediated by GABA receptors in the nervous system. A number of in vitro studies have shown that diverse redox compounds, including redox metabolites and reactive oxygen and nitrogen species, modulate phasic and tonic responses mediated by neuronal GABAA receptors through both presynaptic and postsynaptic mechanisms. We review experimental data showing that many redox agents, which are normally present in neurons and glia or are endogenously generated in these cells under physiologic states or during oxidative stress (e.g., hydrogen peroxide, superoxide and hydroxyl radicals, nitric oxide, ascorbic acid, and glutathione), induce potentiating or inhibiting actions on different native and recombinant GABAA receptor subtypes. Based on these results, it is thought that redox signaling might represent a homeostatic mechanism that regulates the function of synaptic and extrasynaptic GABAA receptors in physiologic and pathologic conditions.
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Affiliation(s)
- Daniel J Calvo
- Laboratorio de Neurobiología Celular y Molecular, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ¨Dr. Héctor N. Torres¨ (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina (D.J.C., A.N.B.G.)
| | - Andrea N Beltrán González
- Laboratorio de Neurobiología Celular y Molecular, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ¨Dr. Héctor N. Torres¨ (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina (D.J.C., A.N.B.G.)
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Cascio MG, Zamberletti E, Marini P, Parolaro D, Pertwee RG. The phytocannabinoid, Δ⁹-tetrahydrocannabivarin, can act through 5-HT₁A receptors to produce antipsychotic effects. Br J Pharmacol 2016; 172:1305-18. [PMID: 25363799 DOI: 10.1111/bph.13000] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/22/2014] [Accepted: 10/28/2014] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND AND PURPOSE This study aimed to address the questions of whether Δ(9)-tetrahydrocannabivarin (THCV) can (i) enhance activation of 5-HT1 A receptors in vitro and (ii) induce any apparent 5-HT₁A receptor-mediated antipsychotic effects in vivo. EXPERIMENTAL APPROACH In vitro studies investigated the effect of THCV on targeting by 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) of 5-HT₁A receptors in membranes obtained from rat brainstem or human 5-HT₁A CHO cells, using [(35)S]-GTPγS and 8-[(3)H]-OH-DPAT binding assays. In vivo studies investigated whether THCV induces signs of 5-HT₁A receptor-mediated antipsychotic effects in rats. KEY RESULTS THCV (i) potently, albeit partially, displaced 8-[(3) H]-OH-DPAT from specific binding sites in rat brainstem membranes; (ii) at 100 nM, significantly enhanced 8-OH-DPAT-induced activation of receptors in these membranes; (iii) produced concentration-related increases in 8-[(3)H]-OH-DPAT binding to specific sites in membranes of human 5-HT₁A receptor-transfected CHO cells; and (iv) at 100 nM, significantly enhanced 8-OH-DPAT-induced activation of these human 5-HT₁A receptors. In phencyclidine-treated rats, THCV, like clozapine (i) reduced stereotyped behaviour; (ii) decreased time spent immobile in the forced swim test; and (iii) normalized hyperlocomotor activity, social behaviour and cognitive performance. Some of these effects were counteracted by the 5-HT₁A receptor antagonist, WAY100635, or could be reproduced by the CB₁ antagonist, AM251. CONCLUSIONS AND IMPLICATIONS Our findings suggest that THCV can enhance 5-HT₁A receptor activation, and that some of its apparent antipsychotic effects may depend on this enhancement. We conclude that THCV has therapeutic potential for ameliorating some of the negative, cognitive and positive symptoms of schizophrenia.
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Affiliation(s)
- Maria Grazia Cascio
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
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Lilius TO, Jokinen V, Neuvonen MS, Niemi M, Kalso EA, Rauhala PV. Ketamine coadministration attenuates morphine tolerance and leads to increased brain concentrations of both drugs in the rat. Br J Pharmacol 2016; 172:2799-813. [PMID: 25297798 PMCID: PMC4439876 DOI: 10.1111/bph.12974] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 09/05/2014] [Accepted: 10/03/2014] [Indexed: 12/25/2022] Open
Abstract
Background and Purpose The effects of ketamine in attenuating morphine tolerance have been suggested to result from a pharmacodynamic interaction. We studied whether ketamine might increase brain morphine concentrations in acute coadministration, in morphine tolerance and morphine withdrawal. Experimental Approach Morphine minipumps (6 mg·day–1) induced tolerance during 5 days in Sprague–Dawley rats, after which s.c. ketamine (10 mg·kg–1) was administered. Tail flick, hot plate and rotarod tests were used for behavioural testing. Serum levels and whole tissue brain and liver concentrations of morphine, morphine-3-glucuronide, ketamine and norketamine were measured using HPLC-tandem mass spectrometry. Key Results In morphine-naïve rats, ketamine caused no antinociception whereas in morphine-tolerant rats there was significant antinociception (57% maximum possible effect in the tail flick test 90 min after administration) lasting up to 150 min. In the brain of morphine-tolerant ketamine-treated rats, the morphine, ketamine and norketamine concentrations were 2.1-, 1.4- and 3.4-fold, respectively, compared with the rats treated with morphine or ketamine only. In the liver of morphine-tolerant ketamine-treated rats, ketamine concentration was sixfold compared with morphine-naïve rats. After a 2 day morphine withdrawal period, smaller but parallel concentration changes were observed. In acute coadministration, ketamine increased the brain morphine concentration by 20%, but no increase in ketamine concentrations or increased antinociception was observed. Conclusions and Implications The ability of ketamine to induce antinociception in rats made tolerant to morphine may also be due to increased brain concentrations of morphine, ketamine and norketamine. The relevance of these findings needs to be assessed in humans.
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Affiliation(s)
- T O Lilius
- Institute of Biomedicine, Pharmacology, University of Helsinki, Finland
| | - V Jokinen
- Institute of Biomedicine, Pharmacology, University of Helsinki, Finland
| | - M S Neuvonen
- Haartman Institute, Department of Clinical Pharmacology, University of Helsinki, Finland
| | - M Niemi
- Haartman Institute, Department of Clinical Pharmacology, University of Helsinki, Finland.,HUSLAB, Helsinki University Central Hospital, Finland
| | - E A Kalso
- Institute of Biomedicine, Pharmacology, University of Helsinki, Finland.,Department of Anaesthesia, Intensive Care Medicine, Emergency Medicine and Pain Medicine, Pain Clinic, Helsinki University Central Hospital, Finland
| | - P V Rauhala
- Institute of Biomedicine, Pharmacology, University of Helsinki, Finland
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Laskaris LE, Di Biase MA, Everall I, Chana G, Christopoulos A, Skafidas E, Cropley VL, Pantelis C. Microglial activation and progressive brain changes in schizophrenia. Br J Pharmacol 2016; 173:666-80. [PMID: 26455353 PMCID: PMC4742288 DOI: 10.1111/bph.13364] [Citation(s) in RCA: 148] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 09/16/2015] [Accepted: 10/06/2015] [Indexed: 12/11/2022] Open
Abstract
Schizophrenia is a debilitating disorder that typically begins in adolescence and is characterized by perceptual abnormalities, delusions, cognitive and behavioural disturbances and functional impairments. While current treatments can be effective, they are often insufficient to alleviate the full range of symptoms. Schizophrenia is associated with structural brain abnormalities including grey and white matter volume loss and impaired connectivity. Recent findings suggest these abnormalities follow a neuroprogressive course in the earliest stages of the illness, which may be associated with episodes of acute relapse. Neuroinflammation has been proposed as a potential mechanism underlying these brain changes, with evidence of increased density and activation of microglia, immune cells resident in the brain, at various stages of the illness. We review evidence for microglial dysfunction in schizophrenia from both neuroimaging and neuropathological data, with a specific focus on studies examining microglial activation in relation to the pathology of grey and white matter. The studies available indicate that the link between microglial dysfunction and brain change in schizophrenia remains an intriguing hypothesis worthy of further examination. Future studies in schizophrenia should: (i) use multimodal imaging to clarify this association by mapping brain changes longitudinally across illness stages in relation to microglial activation; (ii) clarify the nature of microglial dysfunction with markers specific to activation states and phenotypes; (iii) examine the role of microglia and neurons with reference to their overlapping roles in neuroinflammatory pathways; and (iv) examine the impact of novel immunomodulatory treatments on brain structure in schizophrenia.
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Affiliation(s)
- L E Laskaris
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Carlton South, VIC, Australia
- Centre for Neural Engineering, The University of Melbourne, Carlton, VIC, Australia
- Department of Psychiatry, The University of Melbourne, Parkville, VIC, Australia
| | - M A Di Biase
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Carlton South, VIC, Australia
- Department of Psychiatry, The University of Melbourne, Parkville, VIC, Australia
| | - I Everall
- Department of Psychiatry, The University of Melbourne, Parkville, VIC, Australia
- Florey Institute for Neurosciences and Mental Health, Parkville, VIC, Australia
| | - G Chana
- Centre for Neural Engineering, The University of Melbourne, Carlton, VIC, Australia
- Department of Psychiatry, The University of Melbourne, Parkville, VIC, Australia
| | - A Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - E Skafidas
- Centre for Neural Engineering, The University of Melbourne, Carlton, VIC, Australia
- Florey Institute for Neurosciences and Mental Health, Parkville, VIC, Australia
| | - V L Cropley
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Carlton South, VIC, Australia
- Department of Psychiatry, The University of Melbourne, Parkville, VIC, Australia
| | - C Pantelis
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Carlton South, VIC, Australia
- Department of Psychiatry, The University of Melbourne, Parkville, VIC, Australia
- Florey Institute for Neurosciences and Mental Health, Parkville, VIC, Australia
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Utilization of Superfused Cerebral Slices in Probing Muscarinic Receptor Autoregulation of Acetylcholine Release. ACTA ACUST UNITED AC 2016. [DOI: 10.1007/978-1-4939-2858-3_12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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Walford T, Musa FI, Harper AGS. Nicergoline inhibits human platelet Ca(2+) signalling through triggering a microtubule-dependent reorganization of the platelet ultrastructure. Br J Pharmacol 2016; 173:234-47. [PMID: 26450366 PMCID: PMC4813371 DOI: 10.1111/bph.13361] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Revised: 08/27/2015] [Accepted: 09/23/2015] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Recently, we demonstrated that a pericellular Ca(2+) recycling system potentiates agonist-evoked Ca(2+) signalling and granule secretion in human platelets and hypothesized a role for the membrane complex (MC) in orchestrating the accumulation of Ca(2+) in the pericellular region. Previous work has demonstrated that treatment with high concentrations of nicergoline may disrupt the MC through an ability to trigger a re-organization of the dense tubular system. Experiments were therefore performed to assess whether nicergoline-induced changes in platelet ultrastructure affects thrombin-evoked Ca(2+) fluxes and dense granule secretion. EXPERIMENTAL APPROACH Thrombin-evoked Ca(2+) fluxes were monitored in Fura-2- or Fluo-5N-loaded human platelets, or using platelet suspensions containing Fluo-4 or Rhod-5N K(+) salts. Fluorescence microscopy was utilized to monitor microtubule structure and intracellular Ca(2+) store distribution in TubulinTracker- and Fluo-5N-loaded platelets respectively. Dense granule secretion was monitored using luciferin-luciferase. KEY RESULTS Nicergoline treatment inhibited thrombin-evoked Ca(2+) signalling and induced alterations in the microtubule structure and the distribution of intracellular Ca(2+) stores in platelets. Nicergoline altered the generation and spreading of thrombin-induced pericellular Ca(2+) signals and almost completely prevented dense granule secretion. Stabilization of microtubules using taxol reversed most effects of nicergoline on platelet Ca(2+) signalling and partially reversed its effects on dense granule secretion. CONCLUSIONS AND IMPLICATIONS Nicergoline-induced alterations to platelet ultrastructure disrupt platelet Ca(2+) signalling in a manner that would be predicted if the MC had been disrupted. These data suggest that nicergoline may be a useful prototype for the discovery of novel MC-disrupting anti-thrombotics.
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Affiliation(s)
- T Walford
- Institute for Science and Technology in Medicine, Keele University, Guy Hilton Research Centre, Stoke-on-Trent, Staffordshire, UK
| | - F I Musa
- Institute for Science and Technology in Medicine, Keele University, Guy Hilton Research Centre, Stoke-on-Trent, Staffordshire, UK
| | - A G S Harper
- Institute for Science and Technology in Medicine, Keele University, Guy Hilton Research Centre, Stoke-on-Trent, Staffordshire, UK
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14
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Rubil S, Rössler OG, Thiel G. CREB, AP-1, ternary complex factors and MAP kinases connect transient receptor potential melastatin-3 (TRPM3) channel stimulation with increased c-Fos expression. Br J Pharmacol 2015; 173:305-18. [PMID: 26493679 DOI: 10.1111/bph.13372] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 10/08/2015] [Accepted: 10/14/2015] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND AND PURPOSE The rise in intracellular Ca(2+) stimulates the expression of the transcription factor c-Fos. Depending on the mode of entry of Ca(2+) into the cytosol, distinct signal transducers and transcription factors are required. Here, we have analysed the signalling pathway connecting a Ca(2+) influx via activation of transient receptor potential melastatin-3 (TRPM3) channels with enhanced c-Fos expression. EXPERIMENTAL APPROACH Transcription of c-Fos promoter/reporter genes that were integrated into the chromatin via lentiviral gene transfer was analysed in HEK293 cells overexpressing TRPM3. The transcriptional activation potential of c-Fos was measured using a GAL4-c-Fos fusion protein. KEY RESULTS The signalling pathway connecting TRPM3 stimulation with enhanced c-Fos expression requires the activation of MAP kinases. On the transcriptional level, three Ca(2+) -responsive elements, the cAMP-response element and the binding sites for the serum response factor (SRF) and AP-1, are essential for the TRPM3-mediated stimulation of the c-Fos promoter. Ternary complex factors are additionally involved in connecting TRPM3 stimulation with the up-regulation of c-Fos expression. Stimulation of TRPM3 channels also increases the transcriptional activation potential of c-Fos. CONCLUSIONS AND IMPLICATIONS Signalling molecules involved in connecting TRPM3 with the c-Fos gene are MAP kinases and the transcription factors CREB, SRF, AP-1 and ternary complex factors. As c-Fos constitutes, together with other basic region leucine zipper transcription factors, the AP-1 transcription factor complex, the results of this study explain TRPM3-induced activation of AP-1 and connects TRPM3 with the biological functions regulated by AP-1.
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Affiliation(s)
- Sandra Rubil
- Department of Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany
| | - Oliver G Rössler
- Department of Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany
| | - Gerald Thiel
- Department of Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany
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15
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Cross AJ, Widzowski D, Maciag C, Zacco A, Hudzik T, Liu J, Nyberg S, Wood MW. Quetiapine and its metabolite norquetiapine: translation from in vitro pharmacology to in vivo efficacy in rodent models. Br J Pharmacol 2015; 173:155-66. [PMID: 26436896 DOI: 10.1111/bph.13346] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 09/03/2015] [Accepted: 09/24/2015] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Quetiapine has a range of clinical activity distinct from other atypical antipsychotic drugs, demonstrating efficacy as monotherapy in bipolar depression, major depressive disorder and generalized anxiety disorder. The neuropharmacological mechanisms underlying this clinical profile are not completely understood; however, the major active metabolite, norquetiapine, has been shown to have a distinct in vitro pharmacological profile consistent with a broad therapeutic range and may contribute to the clinical profile of quetiapine. EXPERIMENTAL APPROACH We evaluated quetiapine and norquetiapine, using in vitro binding and functional assays of targets known to be associated with antidepressant and anxiolytic drug actions and compared these activities with a representative range of established antipsychotics and antidepressants. To determine how the in vitro pharmacological properties translate into in vivo activity, we used preclinical animal models with translational relevance to established antidepressant-like and anxiolytic-like drug action. KEY RESULTS Norquetiapine had equivalent activity to established antidepressants at the noradrenaline transporter (NET), while quetiapine was inactive. Norquetiapine was active in the mouse forced swimming and rat learned helplessness tests. In in vivo receptor occupancy studies, norquetiapine had significant occupancy at NET at behaviourally relevant doses. Both quetiapine and norquetiapine were agonists at 5-HT1A receptors, and the anxiolytic-like activity of norquetiapine in rat punished responding was blocked by the 5-HT1A antagonist, WAY100635. CONCLUSIONS AND IMPLICATIONS Quetiapine and norquetiapine have multiple in vitro pharmacological actions, and results from preclinical studies suggest that activity at NET and 5-HT1A receptors contributes to the antidepressant and anxiolytic effects in patients treated with quetiapine.
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Affiliation(s)
- A J Cross
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, USA
| | - D Widzowski
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, USA
| | - C Maciag
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, USA
| | - A Zacco
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, USA
| | - T Hudzik
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, USA
| | - J Liu
- AstraZeneca R&D, Shanghai, China
| | - S Nyberg
- AstraZeneca R&D, Södertälje, Sweden
| | - M W Wood
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, USA
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16
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Meng G, Ma Y, Xie L, Ferro A, Ji Y. Emerging role of hydrogen sulfide in hypertension and related cardiovascular diseases. Br J Pharmacol 2015; 172:5501-11. [PMID: 25204754 PMCID: PMC4667855 DOI: 10.1111/bph.12900] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Revised: 08/18/2014] [Accepted: 08/28/2014] [Indexed: 12/31/2022] Open
Abstract
Hydrogen sulfide (H2 S) has traditionally been viewed as a highly toxic gas; however, recent studies have implicated H2 S as a third member of the gasotransmitter family, exhibiting properties similar to NO and carbon monoxide. Accumulating evidence has suggested that H2 S influences a wide range of physiological and pathological processes, among which blood vessel relaxation, cardioprotection and atherosclerosis have been particularly studied. In the cardiovascular system, H2 S production is predominantly catalyzed by cystathionine γ-lyase (CSE). Decreased endogenous H2 S levels have been found in hypertensive patients and animals, and CSE(-/-) mice develop hypertension with age, suggesting that a deficiency in H2 S contributes importantly to BP regulation. H2 S supplementation attenuates hypertension in different hypertensive animal models. The mechanism by which H2 S was originally proposed to attenuate hypertension was by virtue of its action on vascular tone, which may be related to effects on different ion channels. Both H2 S and NO cause vasodilatation and there is cross-talk between these two molecules to regulate BP. Suppression of oxidative stress may also contribute to antihypertensive effects of H2 S. This review also summarizes the state of research on H2 S and hypertension in China. A better understanding of the role of H2 S in hypertension and related cardiovascular diseases will allow novel strategies to be devised for their treatment.
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Affiliation(s)
- Guoliang Meng
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, State Key Laboratory of Reproductive Medicine, Atherosclerosis Research CentreNanjing Medical UniversityNanjingChina
| | - Yan Ma
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, State Key Laboratory of Reproductive Medicine, Atherosclerosis Research CentreNanjing Medical UniversityNanjingChina
| | - Liping Xie
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, State Key Laboratory of Reproductive Medicine, Atherosclerosis Research CentreNanjing Medical UniversityNanjingChina
| | - Albert Ferro
- Department of Clinical PharmacologyCardiovascular DivisionSchool of MedicineKing's College LondonLondonUK
| | - Yong Ji
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, State Key Laboratory of Reproductive Medicine, Atherosclerosis Research CentreNanjing Medical UniversityNanjingChina
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17
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Abstract
This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23
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Affiliation(s)
- Xin Wang
- Faculty of Life SciencesThe University of ManchesterManchesterUK
| | - Yong Ji
- Atherosclerosis Research CentreNanjing Medical UniversityNanjingChina
| | - Baofeng Yang
- Department of PharmacologyHarbin Medical UniversityHarbinChina
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18
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He X, Zhao M, Bi X, Sun L, Yu X, Zhao M, Zang W. Novel strategies and underlying protective mechanisms of modulation of vagal activity in cardiovascular diseases. Br J Pharmacol 2015; 172:5489-500. [PMID: 25378088 PMCID: PMC4667861 DOI: 10.1111/bph.13010] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 10/21/2014] [Accepted: 10/31/2014] [Indexed: 01/14/2023] Open
Abstract
Cardiovascular disease remains a major cause of disability and death worldwide. Autonomic imbalance, characterized by suppressed vagal (parasympathetic) activity and increased sympathetic activity, correlates with various pathological conditions, including heart failure, arrhythmia, ischaemia/reperfusion injury and hypertension. Conventionally, pharmacological interventions, such as β-blocker treatment, have primarily targeted suppressing sympathetic over-activation, while vagal modulation has always been neglected. Emerging evidence has documented the improvement of cardiac and vascular function mediated by the vagal nerve. Many investigators have tried to explore the effective ways to enhance vagal tone and normalize the autonomic nervous system. In this review, we attempt to give an overview of these therapeutic strategies, including direct vagal activation (electrical vagal stimulation, ACh administration and ACh receptor activation), pharmacological modulation (adenosine, cholinesterase inhibitors, statins) and exercise training. This overview provides valuable information for combination therapy, contributing to establishment of a comprehensive system on vagal modulation from the aspects of clinical application and lifestyle improvement. In addition, the mechanisms contributing to the benefits of enhancing vagal tone are diverse and have not yet been fully defined. We endeavour to outline the recent findings that advance our knowledge regarding the many favourable effects exerted by vagal activation: anti-inflammatory pathways, modulation of NOS and NO signalling, regulation of redox state, improvement of mitochondrial biogenesis and function, and potential calcium regulation. This review may help to develop novel therapeutic strategies targeting enhancing vagal activity for the treatment of cardiovascular diseases.
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Affiliation(s)
- Xi He
- Department of PharmacologyXi'an Jiaotong University Health Science CenterXi'anChina
| | - Ming Zhao
- Department of PharmacologyXi'an Jiaotong University Health Science CenterXi'anChina
| | - Xueyuan Bi
- Department of PharmacologyXi'an Jiaotong University Health Science CenterXi'anChina
| | - Lei Sun
- Department of PharmacologyXi'an Jiaotong University Health Science CenterXi'anChina
| | - Xiaojiang Yu
- Department of PharmacologyXi'an Jiaotong University Health Science CenterXi'anChina
| | - Mei Zhao
- Department of PharmacologyXi'an Jiaotong University Health Science CenterXi'anChina
| | - Weijin Zang
- Department of PharmacologyXi'an Jiaotong University Health Science CenterXi'anChina
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19
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Sengmany K, Gregory KJ. Metabotropic glutamate receptor subtype 5: molecular pharmacology, allosteric modulation and stimulus bias. Br J Pharmacol 2015; 173:3001-17. [PMID: 26276909 DOI: 10.1111/bph.13281] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/30/2015] [Accepted: 07/26/2015] [Indexed: 12/12/2022] Open
Abstract
The metabotropic glutamate receptor subtype 5 (mGlu5 ) is a family C GPCR that has been implicated in various neuronal processes and, consequently, in several CNS disorders. Over the past few decades, GPCR-based drug discovery, including that for mGlu5 receptors, has turned considerable attention to targeting allosteric binding sites. Modulation of endogenous agonists by allosteric ligands offers the advantages of spatial and temporal fine-tuning of receptor activity, increased selectivity and reduced adverse effects with the potential to elicit improved clinical outcomes. Further, with greater appreciation of the multifaceted nature of the transduction of mGlu5 receptor signalling, it is increasingly apparent that drug discovery must take into consideration unique receptor conformations and the potential for stimulus-bias. This novel paradigm proposes that different ligands may differentially modulate distinct signalling pathways arising from the same receptor. We review our current understanding of the complexities of mGlu5 receptor signalling and regulation, and how these relate to allosteric ligands. Ultimately, a deeper appreciation of these relationships will provide the foundation for targeted drug design of compounds with increased selectivity, not only for the desired receptor but also for the desired signalling outcome from the receptor. Linked Articles This article is part of a themed section on Molecular Pharmacology of G Protein-Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc.
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Affiliation(s)
- K Sengmany
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - K J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, VIC, Australia.
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20
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Lagatta DC, Ferreira-Junior NC, Resstel LBM. Medial prefrontal cortex TRPV1 channels modulate the baroreflex cardiac activity in rats. Br J Pharmacol 2015; 172:5377-89. [PMID: 26360139 DOI: 10.1111/bph.13327] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 08/18/2015] [Accepted: 08/27/2015] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND AND PURPOSE The ventral portion of the medial prefrontal cortex (vMPFC) comprises the infralimbic (IL), prelimbic (PL) and dorsopenducular (DP) cortices. The IL and PL regions facilitate the baroreceptor reflex arc. This facilitatory effect on the baroreflex is thought to be mediated by vMPFC glutamatergic transmission, through NMDA receptors. The glutamatergic transmission can be modulated by other neurotransmitters, such as the endocannabinoids, which are agonists of the TRPV1 receptor. TRPV1 channels facilitate glutamatergic transmission in the brain. Thus, we hypothesized that TRPV1 receptors in the vMPFC enhance the cardiac baroreflex response. EXPERIMENTAL APPROACH Stainless steel guide cannulae were bilaterally implanted into the vMPFC of male Wistar rats. Afterwards, a catheter was inserted into the femoral artery, for recording MAP and HR, and into the femoral vein for assessing baroreflex activation. KEY RESULTS Microinjections of the TRPV1 receptor antagonists capsazepine and 6-iodo-nordihydrocapsaicin (6-IODO) into the vMPFC reduced the cardiac baroreflex activity in unanaesthetized rats. Capsaicin microinjected into the vMPFC increased the cardiac baroreflex activity in unanaesthetized rats. When an ineffective dose of the TRPV1 receptor antagonist 6-IODO was used, the capsaicin-induced increase in the cardiac baroreflex response was abolished. The higher doses of capsaicin administered into the vMPFC after the ineffective dose of 6-IODO displaced the dose-response curve of the baroreflex parameters to the right, with no alteration in the maximum effect of capsaicin. CONCLUSIONS AND IMPLICATIONS The results of the present study show that stimulation of the TRPV1 receptors in the vMPFC increases the cardiac baroreceptor reflex response.
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Affiliation(s)
- D C Lagatta
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - N C Ferreira-Junior
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - L B M Resstel
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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21
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McPartland JM, Duncan M, Di Marzo V, Pertwee RG. Are cannabidiol and Δ(9) -tetrahydrocannabivarin negative modulators of the endocannabinoid system? A systematic review. Br J Pharmacol 2015; 172:737-53. [PMID: 25257544 DOI: 10.1111/bph.12944] [Citation(s) in RCA: 358] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 09/12/2014] [Accepted: 09/16/2014] [Indexed: 12/12/2022] Open
Abstract
Based upon evidence that the therapeutic properties of Cannabis preparations are not solely dependent upon the presence of Δ(9) -tetrahydrocannabinol (THC), pharmacological studies have been recently carried out with other plant cannabinoids (phytocannabinoids), particularly cannabidiol (CBD) and Δ(9) -tetrahydrocannabivarin (THCV). Results from some of these studies have fostered the view that CBD and THCV modulate the effects of THC via direct blockade of cannabinoid CB1 receptors, thus behaving like first-generation CB1 receptor inverse agonists, such as rimonabant. Here, we review in vitro and ex vivo mechanistic studies of CBD and THCV, and synthesize data from these studies in a meta-analysis. Synthesized data regarding mechanisms are then used to interpret results from recent pre-clinical animal studies and clinical trials. The evidence indicates that CBD and THCV are not rimonabant-like in their action and thus appear very unlikely to produce unwanted CNS effects. They exhibit markedly disparate pharmacological profiles particularly at CB1 receptors: CBD is a very low-affinity CB1 ligand that can nevertheless affect CB1 receptor activity in vivo in an indirect manner, while THCV is a high-affinity CB1 receptor ligand and potent antagonist in vitro and yet only occasionally produces effects in vivo resulting from CB1 receptor antagonism. THCV has also high affinity for CB2 receptors and signals as a partial agonist, differing from both CBD and rimonabant. These cannabinoids illustrate how in vitro mechanistic studies do not always predict in vivo pharmacology and underlie the necessity of testing compounds in vivo before drawing any conclusion on their functional activity at a given target.
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Affiliation(s)
- John M McPartland
- Division of Molecular Biology, GW Pharmaceuticals, Salisbury, Wiltshire, UK
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22
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Luger D, Poli G, Wieder M, Stadler M, Ke S, Ernst M, Hohaus A, Linder T, Seidel T, Langer T, Khom S, Hering S. Identification of the putative binding pocket of valerenic acid on GABAA receptors using docking studies and site-directed mutagenesis. Br J Pharmacol 2015; 172:5403-13. [PMID: 26375408 PMCID: PMC4988470 DOI: 10.1111/bph.13329] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 08/25/2015] [Accepted: 08/30/2015] [Indexed: 12/15/2022] Open
Abstract
Background and Purpose β2/3‐subunit‐selective modulation of GABAA receptors by valerenic acid (VA) is determined by the presence of transmembrane residue β2/3N265. Currently, it is not known whether β2/3N265 is part of VA's binding pocket or is involved in the transduction pathway of VA's action. The aim of this study was to clarify the localization of VA's binding pocket on GABAA receptors. Experimental Approach Docking and a structure‐based three‐dimensional pharmacophore were employed to identify candidate amino acid residues that are likely to interact with VA. Selected amino acid residues were mutated, and VA‐induced modulation of the resulting GABAA receptors expressed in Xenopus oocytes was analysed. Key Results A binding pocket for VA at the β+/α− interface encompassing amino acid β3N265 was predicted. Mutational analysis of suggested amino acid residues revealed a complete loss of VA's activity on β3M286W channels as well as significantly decreased efficacy and potency of VA on β3N265S and β3F289S receptors. In addition, reduced efficacy of VA‐induced IGABA enhancement was also observed for α1M235W, β3R269A and β3M286A constructs. Conclusions and Implications Our data suggest that amino acid residues β3N265, β3F289, β3M286, β3R269 in the β3 subunit, at or near the etomidate/propofol binding site(s), form part of a VA binding pocket. The identification of the binding pocket for VA is essential for elucidating its pharmacological effects and might also help to develop new selective GABAA receptor ligands.
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Affiliation(s)
- D Luger
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - G Poli
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | - M Wieder
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - M Stadler
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - S Ke
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - M Ernst
- Department of Molecular Neurosciences, Center of Brain Research, Medical University of Vienna, Vienna, Austria
| | - A Hohaus
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - T Linder
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - T Seidel
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - T Langer
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - S Khom
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - S Hering
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
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23
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Santiago E, Climent B, Muñoz M, García-Sacristán A, Rivera L, Prieto D. Hydrogen peroxide activates store-operated Ca(2+) entry in coronary arteries. Br J Pharmacol 2015; 172:5318-32. [PMID: 26478127 DOI: 10.1111/bph.13322] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 08/20/2015] [Accepted: 09/06/2015] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Abnormal Ca(2+) metabolism has been involved in the pathogenesis of vascular dysfunction associated with oxidative stress. Here, we have investigated the actions of H2 O2 on store-operated Ca(2+) (SOC) entry in coronary arteries and assessed whether it is impaired in arteries from a rat model of metabolic syndrome. EXPERIMENTAL APPROACH Simultaneous measurements of intracellular Ca(2+) concentration and contractile responses were made in coronary arteries from Wistar and obese Zucker rats, mounted in microvascular myographs, and the effects of H2 O2 were assessed. KEY RESULTS H2 O2 raised intracellular Ca(2+) concentrations, accompanied by simultaneous vasoconstriction that was markedly reduced in a Ca(2+) -free medium. Upon Ca(2+) re-addition, a nifedipine-resistant sustained Ca(2+) entry, not coupled to contraction, was obtained in endothelium-denuded coronary arteries. The effect of H2 O2 on this voltage-independent Ca(2+) influx was concentration-dependent, and high micromolar H2 O2 concentrations were inhibitory and reduced SOC entry evoked by inhibition of the sarcoplasmic reticulum ATPase (SERCA). H2 O2 -induced increases in Fura signals were mimicked by Ba(2+) and reduced by heparin, Gd(3+) ions and by Pyr6, a selective inhibitor of the Orai1-mediated Ca(2+) entry,. In coronary arteries from obese Zucker rats, intracellular Ca(2+) mobilization and SOC entry activated by acute exposure to H2 O2 were augmented and associated with local oxidative stress. CONCLUSION AND IMPLICATIONS H2 O2 exerted dual concentration-dependent stimulatory/inhibitory effects on store-operated, IP3 receptor-mediated and Orai1-mediated Ca(2+) entry, not coupled to vasoconstriction in coronary vascular smooth muscle. SOC entry activated by H2 O2 was enhanced and associated with vascular oxidative stress in coronary arteries in metabolic syndrome.
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Affiliation(s)
- Elvira Santiago
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Belén Climent
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Mercedes Muñoz
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Albino García-Sacristán
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Luis Rivera
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Dolores Prieto
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
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Schrage R, De Min A, Hochheiser K, Kostenis E, Mohr K. Superagonism at G protein-coupled receptors and beyond. Br J Pharmacol 2015; 173:3018-27. [PMID: 26276510 DOI: 10.1111/bph.13278] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 07/01/2015] [Accepted: 08/08/2015] [Indexed: 12/18/2022] Open
Abstract
Ligands targeting GPCRs can be categorized according to their intrinsic efficacy to trigger a specific, receptor-mediated response. A ligand endowed with the same level of efficacy as the endogenous agonist can be classified as a full agonist, whereas a compound that displays greater efficacy, that is, higher receptor signalling output than the endogenous agonist, can be called a superagonist. Subsequent to GPCR activation, an intracellular signalling cascade is set in motion, which may generate substantial amplification of the signal. This may obscure superagonism in pharmacological assays and, therefore, the definition of superagonism necessitates a combination of operational approaches, reduction of spare receptors or estimation of receptor activation close to the receptor level to quantify relative agonist efficacies in a particular system. The first part of this review will compare GPCR superagonism with superagonism in the field of immunology, where this term is well established. In the second part, known GPCR superagonists will be reviewed. Then, the experimental and analytical challenges in the deconvolution of GPCR superagonism will be addressed. Finally, the potential benefit of superagonism is discussed. The molecular mechanisms behind GPCR superagonism are not completely understood. However, crystallography shows that agonist binding alone is not sufficient for a fully active receptor state and that binding of the G protein is at least equally important. Accordingly, the emerging number of reported superagonists implies that ligand-induced receptor conformations more active than the ones stabilized by the endogenous agonist are indeed feasible. Superagonists may have therapeutic potential when receptor function is impaired or to induce negative feedback mechanisms. Linked Articles This article is part of a themed section on Molecular Pharmacology of G Protein-Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc.
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Affiliation(s)
- R Schrage
- Pharmacology & Toxicology Section, Institute of Pharmacy, University of Bonn, 53121, Bonn, Germany.
| | - A De Min
- Pharmacology & Toxicology Section, Institute of Pharmacy, University of Bonn, 53121, Bonn, Germany
| | - K Hochheiser
- Peter Doherty Institute, Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC, 3100, Australia
| | - E Kostenis
- Molecular-, Cellular-, and Pharmacobiology Section, Institute of Pharmaceutical Biology, University of Bonn, 53115, Bonn, Germany
| | - K Mohr
- Pharmacology & Toxicology Section, Institute of Pharmacy, University of Bonn, 53121, Bonn, Germany
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Zhou J, Luo Y, Zhang JT, Li MX, Wang CM, Guan XL, Wu PF, Hu ZL, Jin Y, Ni L, Wang F, Chen JG. Propranolol decreases retention of fear memory by modulating the stability of surface glutamate receptor GluA1 subunits in the lateral amygdala. Br J Pharmacol 2015; 172:5068-82. [PMID: 26228348 DOI: 10.1111/bph.13272] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Revised: 07/21/2015] [Accepted: 07/27/2015] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE Posttraumatic stress disorder (PTSD) is a mental disorder with enhanced retention of fear memory and has profound impact on quality of life for millions of people worldwide. The β-adrenoceptor antagonist propranolol has been used in preclinical and clinical studies for the treatment of PTSD, but the mechanisms underlying its potential efficacy on fear memory retention remain to be elucidated. EXPERIMENTAL APPROACH We investigated the action of propranolol on the retention of conditioned fear memory, the surface expression of glutamate receptor GluA1 subunits of AMPA receptors and synaptic adaptation in the lateral amygdala (LA) of rats. KEY RESULTS Propranolol attenuated reactivation-induced strengthening of fear retention while reducing enhanced surface expression of GluA1 subunits and restoring the impaired long-term depression in LA. These effects of propranolol were mediated by antagonizing reactivation-induced enhancement of adrenergic signalling, which activates PKA and calcium/calmodulin-dependent protein kinase II and then regulates the trafficking of AMPA receptors via phosphorylation of GluA1 subunits at the C-terminus. Both i.p. injection and intra-amygdala infusion of propranolol attenuated reactivation-induced enhancement of fear retention. CONCLUSIONS AND IMPLICATIONS Reactivation strengthens fear retention by increasing the level of noradrenaline and promotes the surface expression of GluA1 subunits and the excitatory synaptic transmission in LA. These findings uncover one mechanism underlying the efficiency of propranolol on retention of fear memories and suggest that β-adrenoceptor antagonists, which act centrally, may be more suitable for the treatment of PTSD.
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Affiliation(s)
- Jun Zhou
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yi Luo
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jie-Ting Zhang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ming-Xing Li
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Can-Ming Wang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xin-Lei Guan
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Peng-Fei Wu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Laboratory of Neuropsychiatric Diseases, The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China
| | - Zhuang-Li Hu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Laboratory of Neuropsychiatric Diseases, The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China
| | - You Jin
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lan Ni
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fang Wang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Laboratory of Neuropsychiatric Diseases, The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China.,Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, China.,The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan, China
| | - Jian-Guo Chen
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Laboratory of Neuropsychiatric Diseases, The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China.,Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, China.,The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan, China
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Klinger F, Bajric M, Salzer I, Dorostkar MM, Khan D, Pollak DD, Kubista H, Boehm S, Koenig X. δ Subunit-containing GABAA receptors are preferred targets for the centrally acting analgesic flupirtine. Br J Pharmacol 2015. [PMID: 26211808 PMCID: PMC4621994 DOI: 10.1111/bph.13262] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Background and Purpose The Kv7 channel activator flupirtine is a clinical analgesic characterized as ‘selective neuronal potassium channel opener’. Flupirtine was found to exert comparable actions at GABAA receptors and Kv7 channels in neurons of pain pathways, but not in hippocampus. Experimental Approach Expression patterns of GABAA receptors were explored in immunoblots of rat dorsal root ganglia, dorsal horns and hippocampi using antibodies for 10 different subunits. Effects of flupirtine on recombinant and native GABAA receptors were investigated in patch clamp experiments and compared with the actions on Kv7 channels. Key Results Immunoblots pointed towards α2, α3, β3 and γ2 subunits as targets, but in all γ2‐containing receptors the effects of flupirtine were alike: leftward shift of GABA concentration‐response curves and diminished maximal amplitudes. After replacement of γ2S by δ, flupirtine increased maximal amplitudes. Currents through α1β2δ receptors were more enhanced than those through Kv7 channels. In hippocampal neurons, flupirtine prolonged inhibitory postsynaptic currents, left miniature inhibitory postsynaptic currents (mIPSCs) unaltered and increased bicuculline‐sensitive tonic currents; penicillin abolished mIPSCs, but not tonic currents; concentration‐response curves for GABA‐induced currents were shifted to the left by flupirtine without changes in maximal amplitudes; in the presence of penicillin, maximal amplitudes were increased; GABA‐induced currents in the presence of penicillin were more sensitive towards flupirtine than K+ currents. In dorsal horn neurons, currents evoked by the δ‐preferring agonist THIP (gaboxadol) were more sensitive towards flupirtine than K+ currents. Conclusions and Implications Flupirtine prefers δ‐containing GABAA receptors over γ‐containing ones and over Kv7 channels.
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Affiliation(s)
- Felicia Klinger
- Department of Neurophysiology and Neuropharmacology, Centre for Physiology and Pharmacology, Medical University of Vienna, Spitalgasse 23, Vienna, 1090, Austria
| | - Mirnes Bajric
- Department of Neurophysiology and Neuropharmacology, Centre for Physiology and Pharmacology, Medical University of Vienna, Spitalgasse 23, Vienna, 1090, Austria
| | - Isabella Salzer
- Department of Neurophysiology and Neuropharmacology, Centre for Physiology and Pharmacology, Medical University of Vienna, Spitalgasse 23, Vienna, 1090, Austria
| | - Mario M Dorostkar
- Department of Neurophysiology and Neuropharmacology, Centre for Physiology and Pharmacology, Medical University of Vienna, Spitalgasse 23, Vienna, 1090, Austria
| | - Deeba Khan
- Department of Neurophysiology and Neuropharmacology, Centre for Physiology and Pharmacology, Medical University of Vienna, Spitalgasse 23, Vienna, 1090, Austria
| | - Daniela D Pollak
- Department of Neurophysiology and Neuropharmacology, Centre for Physiology and Pharmacology, Medical University of Vienna, Spitalgasse 23, Vienna, 1090, Austria
| | - Helmut Kubista
- Department of Neurophysiology and Neuropharmacology, Centre for Physiology and Pharmacology, Medical University of Vienna, Spitalgasse 23, Vienna, 1090, Austria
| | - Stefan Boehm
- Department of Neurophysiology and Neuropharmacology, Centre for Physiology and Pharmacology, Medical University of Vienna, Spitalgasse 23, Vienna, 1090, Austria
| | - Xaver Koenig
- Department of Neurophysiology and Neuropharmacology, Centre for Physiology and Pharmacology, Medical University of Vienna, Spitalgasse 23, Vienna, 1090, Austria
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Reiss C, Mindukshev I, Bischoff V, Subramanian H, Kehrer L, Friebe A, Stasch JP, Gambaryan S, Walter U. The sGC stimulator riociguat inhibits platelet function in washed platelets but not in whole blood. Br J Pharmacol 2015; 172:5199-210. [PMID: 26282717 DOI: 10.1111/bph.13286] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 07/23/2015] [Accepted: 08/10/2015] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE Stimulation of soluble guanylyl cyclase (sGC) is a valuable therapeutic strategy for the treatment of several cardiovascular diseases. The sGC stimulator riociguat has been approved for the treatment of two forms of pulmonary hypertension. Platelets contain large amounts of sGC and play a key role in the regulation of haemostasis. Therefore, we investigated the effects of riociguat on platelet function. EXPERIMENTAL APPROACH The effect of riociguat treatment on human platelet activation and aggregation was investigated. The sGC-specific effects of riociguat were determined by comparing wild-type and platelet-specific sGC-knockout mice. KEY RESULTS Riociguat induced cGMP synthesis and subsequent PKG activation in human platelets, suggesting that the inhibitory effects are mediated by cGMP signalling. This finding was confirmed when sGC-knockout platelets were not inhibited by riociguat. In washed human platelets, 100 nM riociguat reduced ADP-induced GPIIb/IIIa activation, while a 10-fold higher concentration was required to reduce convulxin-stimulated GPIIb/IIIa activation. Riociguat inhibited ADP-induced platelet shape change and aggregation, while ATP-induced shape change remained unaffected. However, in PRP and whole blood, 50-100 μM riociguat was required to inhibit platelet activation and aggregation. Riociguat in combination with iloprost significantly inhibited platelet aggregation, even in whole blood. CONCLUSIONS AND IMPLICATIONS Riociguat inhibits platelet activation in whole blood only at concentrations above 50 μM, while the plasma concentrations in riociguat-treated patients are 150 to 500 nM. This finding indicates that riociguat treatment does not affect platelet function in patients. Nevertheless, the possibility that riociguat acts synergistically with iloprost to inhibit platelet activation should be considered.
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Affiliation(s)
- C Reiss
- Centre for Thrombosis and Hemostasis, Johannes Gutenberg University Medical Centre Mainz, Mainz, Germany
| | - I Mindukshev
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - V Bischoff
- Centre for Thrombosis and Hemostasis, Johannes Gutenberg University Medical Centre Mainz, Mainz, Germany
| | - H Subramanian
- Centre for Thrombosis and Hemostasis, Johannes Gutenberg University Medical Centre Mainz, Mainz, Germany.,Institute of Experimental Cardiovascular Research, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - L Kehrer
- Institute of Clinical Biochemistry and Pathobiochemistry, University of Wuerzburg, Wuerzburg, Germany.,Institute of Physiology, University of Wuerzburg, Wuerzburg, Germany
| | - A Friebe
- Institute of Physiology, University of Wuerzburg, Wuerzburg, Germany
| | - J-P Stasch
- Cardiology Research, Bayer Pharma AG, Wuppertal, Germany
| | - S Gambaryan
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.,Department of Cytology and Histology, St. Petersburg State University, St. Petersburg, Russia
| | - U Walter
- Centre for Thrombosis and Hemostasis, Johannes Gutenberg University Medical Centre Mainz, Mainz, Germany
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28
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Potasiewicz A, Kos T, Ravazzini F, Puia G, Arias HR, Popik P, Nikiforuk A. Pro-cognitive activity in rats of 3-furan-2-yl-N-p-tolyl-acrylamide, a positive allosteric modulator of the α7 nicotinic acetylcholine receptor. Br J Pharmacol 2015; 172:5123-35. [PMID: 26276349 DOI: 10.1111/bph.13277] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 07/21/2015] [Accepted: 07/27/2015] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND AND PURPOSE α7 nicotinic acetylcholine receptors (α7 nAChRs) may represent useful targets for cognitive improvement. The aim of this study is to compare the pro-cognitive activity of selective α7-nAChR ligands, including the partial agonists, DMXBA and A-582941, as well as the positive allosteric modulator, 3-furan-2-yl-N-p-tolyl-acrylamide (PAM-2). EXPERIMENTAL APPROACH The attentional set-shifting task (ASST) and the novel object recognition task (NORT) in rats, were used to evaluate the pro-cognitive activity of each ligand [i.e., PAM-2 (0.5, 1.0, and 2.0 mg·kg(-1) ), DMXBA and A-582941 (0.3 and 1.0 mg·kg(-1) )], in the absence and presence of methyllycaconitine (MLA), a selective competitive antagonist. To determine potential drug interactions, an inactive dose of PAM-2 (0.5 mg·kg(-1) ) was co-injected with inactive doses of either agonist - DMXBA: 0.1 (NORT); 0.3 mg·kg(-1) (ASST) or A-582941: 0.1 mg·kg(-1) . KEY RESULTS PAM-2, DMXBA, and A-582941 improved cognition in a MLA-dependent manner, indicating that the observed activities are mediated by α7 nAChRs. Interestingly, the co-injection of inactive doses of PAM-2 and DMXBA or A-582941 also improved cognition, suggesting drug interactions. Moreover, PAM-2 reversed the scopolamine-induced NORT deficit. The electrophysiological results also support the view that PAM-2 potentiates the α7 nAChR currents elicited by a fixed concentration (3 μM) of DMXBA with apparent EC50 = 34 ± 3 μM and Emax = 225 ± 5 %. CONCLUSIONS AND IMPLICATIONS Our results support the view that α7 nAChRs are involved in cognition processes and that PAM-2 is a novel promising candidate for the treatment of cognitive disorders.
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Affiliation(s)
- A Potasiewicz
- Behavioral Neuroscience and Drug Development, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343, Kraków, Poland
| | - T Kos
- Behavioral Neuroscience and Drug Development, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343, Kraków, Poland
| | - F Ravazzini
- Department of Life Science, University of Modena and Reggio Emilia, Modena, Italy
| | - G Puia
- Department of Life Science, University of Modena and Reggio Emilia, Modena, Italy
| | - H R Arias
- Department of Medical Education, California Northstate University College of Medicine, CA, 95757, USA
| | - P Popik
- Behavioral Neuroscience and Drug Development, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343, Kraków, Poland
| | - A Nikiforuk
- Behavioral Neuroscience and Drug Development, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343, Kraków, Poland
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29
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Saez NJ, Deplazes E, Cristofori-Armstrong B, Chassagnon IR, Lin X, Mobli M, Mark AE, Rash LD, King GF. Molecular dynamics and functional studies define a hot spot of crystal contacts essential for PcTx1 inhibition of acid-sensing ion channel 1a. Br J Pharmacol 2015; 172:4985-95. [PMID: 26248594 DOI: 10.1111/bph.13267] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 06/29/2015] [Accepted: 07/13/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE The spider-venom peptide PcTx1 is the most potent and selective inhibitor of acid-sensing ion channel (ASIC) 1a. It has centrally acting analgesic activity and is neuroprotective in rodent models of ischaemic stroke. Understanding the molecular details of the PcTx1 : ASIC1a interaction should facilitate development of therapeutically useful ASIC1a modulators. Previously, we showed that several key pharmacophore residues of PcTx1 reside in a dynamic β-hairpin loop; conclusions confirmed by recent crystal structures of the complex formed between PcTx1 and chicken ASIC1 (cASIC1). Numerous peptide : channel contacts were observed in these crystal structures, but it remains unclear which of these are functionally important. EXPERIMENTAL APPROACH We combined molecular dynamics (MD) simulations of the PcTx1 : cASIC1 complex with mutagenesis of PcTx1 and rat ASIC1a. KEY RESULTS Crystal structures of the PcTx1 : cASIC1 complex indicated that 15 PcTx1 residues form a total of 57 pairwise intermolecular contacts (<5 Å) with 32 channel residues. MD simulations, however, suggested that about half of these interactions do not persist in solution. Mutation to alanine of only eight of 15 PcTx1 contact residues substantially altered ASIC1a inhibition by PcTx1. Our data reveal that many of the peptide-channel interactions observed in the PcTx1 : cASIC1 crystal structures are not important for PcTx1 inhibition of rat ASIC1a. CONCLUSIONS AND IMPLICATIONS We identified the atomic interactions that are critical for PcTx1 inhibition of ASIC1a. Our data highlight the value of combining structural information, MD and functional experiments to obtain detailed insight into the molecular basis of protein : protein interactions.
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Affiliation(s)
- Natalie J Saez
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Evelyne Deplazes
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Ben Cristofori-Armstrong
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Irène R Chassagnon
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | | | - Mehdi Mobli
- Centre for Advanced Imaging, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Alan E Mark
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Lachlan D Rash
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia
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30
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Kolisnyk B, Al-Onaizi MA, Prado VF, Prado MAM. α7 nicotinic ACh receptor-deficient mice exhibit sustained attention impairments that are reversed by β2 nicotinic ACh receptor activation. Br J Pharmacol 2015. [PMID: 26222090 DOI: 10.1111/bph.13260] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE Disruptions of executive function, including attentional deficits, are a hallmark of a number of diseases. ACh in the prefrontal cortex regulates attentive behaviour; however, the role of α7 nicotinic ACh receptor (α7nAChR) in attention is contentious. EXPERIMENTAL APPROACH In order to probe attention, we trained both wild-type and α7nAChR knockout mice on a touch screen-based five-choice serial reaction time task (5-CSRT). Following training procedures, we then tested sustained attention using a probe trial experiment. To further differentiate the role of specific nicotinic receptors in attention, we then tested the effects of both α7nAChR and β2nAChR agonists on the performance of both wild-type and knockout mice on the 5-CSRT task. KEY RESULTS At low doses, α7nAChR agonists improved attentional performance of wild-type mice, while high doses had deleterious effects on attention. α7nAChR knockout mice displayed deficits in sustained attention that were not ameliorated by α7nAChR agonists. However, these deficits were completely reversed by the administration of a β2nAChR agonist. Furthermore, administration of a β2nAChR agonist in α7nAChR knockout mice elicited similar biochemical response in the prefrontal cortex as the administration of α7nAChR agonists in wild-type mice. CONCLUSIONS AND IMPLICATIONS Our experiments reveal an intricate relationship between distinct nicotinic receptors to regulate attentional performance and provide the basis for targeting β2nAChRs pharmacologically to decrease attentional deficits due to a dysfunction in α7nAChRs.
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Affiliation(s)
- Benjamin Kolisnyk
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada
| | - Mohammed A Al-Onaizi
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.,Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, Canada
| | - Vania F Prado
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.,Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, Canada
| | - Marco A M Prado
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.,Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, Canada
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31
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Peters E, Geraci S, Heemskerk S, Wilmer MJ, Bilos A, Kraenzlin B, Gretz N, Pickkers P, Masereeuw R. Alkaline phosphatase protects against renal inflammation through dephosphorylation of lipopolysaccharide and adenosine triphosphate. Br J Pharmacol 2015. [PMID: 26222228 DOI: 10.1111/bph.13261] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE Recently, two phase-II trials demonstrated improved renal function in critically ill patients with sepsis-associated acute kidney injury treated with the enzyme alkaline phosphatase. Here, we elucidated the dual active effect on renal protection of alkaline phosphatase. EXPERIMENTAL APPROACH The effect of human recombinant alkaline phosphatase (recAP) on LPS-induced renal injury was studied in Sprague-Dawley rats. Renal function was assessed by transcutaneous measurement of FITC-sinistrin elimination in freely moving, awake rats. The mechanism of action of recAP was further investigated in vitro using conditionally immortalized human proximal tubular epithelial cells (ciPTEC). KEY RESULTS In vivo, LPS administration significantly prolonged FITC-sinistrin half-life and increased fractional urea excretion, which was prevented by recAP co-administration. Moreover, recAP prevented LPS-induced increase in proximal tubule injury marker, kidney injury molecule-1 expression and excretion. In vitro, LPS-induced production of TNF-α, IL-6 and IL-8 was significantly attenuated by recAP. This effect was linked to dephosphorylation, as enzymatically inactive recAP had no effect on LPS-induced cytokine production. RecAP-mediated protection resulted in increased adenosine levels through dephosphorylation of LPS-induced extracellular ADP and ATP. Also, recAP attenuated LPS-induced increased expression of adenosine A2A receptor. However, the A2A receptor antagonist ZM-241385 did not diminish the effects of recAP. CONCLUSIONS AND IMPLICATIONS These results indicate that the ability of recAP to reduce renal inflammation may account for the beneficial effect observed in septic acute kidney injury patients, and that dephosphorylation of ATP and LPS are responsible for this protective effect.
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Affiliation(s)
- E Peters
- Department of Intensive Care Medicine, Radboud university medical center, Nijmegen, The Netherlands.,Department of Pharmacology and Toxicology, Radboud university medical center, Nijmegen, The Netherlands
| | - S Geraci
- Medical Research Center, University of Heidelberg, Mannheim, Germany
| | - S Heemskerk
- Department of Intensive Care Medicine, Radboud university medical center, Nijmegen, The Netherlands.,Department of Pharmacology and Toxicology, Radboud university medical center, Nijmegen, The Netherlands
| | - M J Wilmer
- Department of Pharmacology and Toxicology, Radboud university medical center, Nijmegen, The Netherlands
| | - A Bilos
- Department of Pharmacology and Toxicology, Radboud university medical center, Nijmegen, The Netherlands
| | - B Kraenzlin
- Medical Research Center, University of Heidelberg, Mannheim, Germany
| | - N Gretz
- Medical Research Center, University of Heidelberg, Mannheim, Germany
| | - P Pickkers
- Department of Intensive Care Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - R Masereeuw
- Department of Pharmacology and Toxicology, Radboud university medical center, Nijmegen, The Netherlands.,Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands
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Laurent V, Morse AK, Balleine BW. The role of opioid processes in reward and decision-making. Br J Pharmacol 2015; 172:449-59. [PMID: 24930675 DOI: 10.1111/bph.12818] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 05/02/2014] [Accepted: 05/15/2014] [Indexed: 01/15/2023] Open
Abstract
UNLABELLED Contemporary theories emphasize the involvement of the endogenous opioid system in assigning hedonic values to rewards. Although earlier research supports this view, recent findings suggest that opioids play a larger and more complex role in reward processes than these theories suggest. For example, opioid activity in the basolateral amygdala is required for encoding incentive learning, a process by which the value of goal-directed actions is updated. Outside the amygdala, opioid receptors in the ventral striatum have been found to promote choice between different courses of action. Specifically, μ opioid receptors in the nucleus accumbens core and δ opioid receptors in the nucleus accumbens shell have been reported to mediate distinct aspects of incentive motivation; the core regulating the effect of experienced reward and the shell of predicted reward on choice. In both cases, the involvement of opioid receptors was restricted to the time of choice, although changes in their expression pattern could be observed prior to that point. This time-restricted involvement of opioid receptor-related processes is consistent with the view that opioids in the nucleus accumbens are central components of the limbic-motor interface, integrating reward-related information with instrumental learning to guide decision-making, particularly the selection and execution of goal-directed actions. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
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Affiliation(s)
- Vincent Laurent
- Behavioural Neuroscience Laboratory, Brain and Mind Research Institute, The University of Sydney, Sydney, NSW, Australia
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Abstract
The variety of physiological functions controlled by dopamine in the brain and periphery is mediated by the D1, D2, D3, D4 and D5 dopamine GPCRs. Drugs acting on dopamine receptors are significant tools for the management of several neuropsychiatric disorders including schizophrenia, bipolar disorder, depression and Parkinson's disease. Recent investigations of dopamine receptor signalling have shown that dopamine receptors, apart from their canonical action on cAMP-mediated signalling, can regulate a myriad of cellular responses to fine-tune the expression of dopamine-associated behaviours and functions. Such signalling mechanisms may involve alternate G protein coupling or non-G protein mechanisms involving ion channels, receptor tyrosine kinases or proteins such as β-arrestins that are classically involved in GPCR desensitization. Another level of complexity is the growing appreciation of the physiological roles played by dopamine receptor heteromers. Applications of new in vivo techniques have significantly furthered the understanding of the physiological functions played by dopamine receptors. Here we provide an update of the current knowledge regarding the complex biology, signalling, physiology and pharmacology of dopamine receptors.
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Hao Y, Liu TT, He ZG, Wu W, Xiang HB. Hypothesis: CeM-PAG GABAergic circuits may be implicated in sudden unexpected death in epilepsy by melanocortinergic signaling. Epilepsy Behav 2015; 50:25-8. [PMID: 26101104 DOI: 10.1016/j.yebeh.2015.04.070] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Accepted: 04/29/2015] [Indexed: 12/12/2022]
Affiliation(s)
- Yan Hao
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, People's Republic of China
| | - Tao-Tao Liu
- Department of Anesthesiology and Pain Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, People's Republic of China
| | - Zhi-Gang He
- Department of Anesthesiology and Pain Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, People's Republic of China
| | - Wei Wu
- Department of Orthopaedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, People's Republic of China.
| | - Hong-Bing Xiang
- Department of Anesthesiology and Pain Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, People's Republic of China.
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Hyland NP, Golubeva AV. GABA B receptors in the bladder and bowel: therapeutic potential for positive allosteric modulators?: Commentary on Kalinichev et al., Br J Pharmacol 171: 995-1006. Br J Pharmacol 2015; 172:4588-4590. [PMID: 24641323 DOI: 10.1111/bph.12617] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 01/16/2014] [Accepted: 01/30/2014] [Indexed: 02/01/2023] Open
Abstract
LINKED ARTICLE This article is a Commentary on Kalinichev M, Palea S, Haddouk H, Royer-Urios I, Guilloteau V, Lluel P, Schneider M, Saporito M and Poli S (2014). ADX71441, a novel, potent and selective positive allosteric modulator of the GABAB receptor, shows efficacy in rodent models of overactive bladder. Br J Pharmacol 171: 995-1006. doi: 10.1111/bph.12517.
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Affiliation(s)
- Niall P Hyland
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.,Department of Pharmacology & Therapeutics, University College Cork, Cork, Ireland
| | - Anna V Golubeva
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
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Kaji I, Akiba Y, Said H, Narimatsu K, Kaunitz JD. Luminal 5-HT stimulates colonic bicarbonate secretion in rats. Br J Pharmacol 2015; 172:4655-70. [PMID: 26061462 DOI: 10.1111/bph.13216] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 04/16/2015] [Accepted: 05/09/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE The bioactive monoamine 5-HT, implicated in the pathogenesis of functional gastrointestinal disorders, is abundantly synthesized and stored in rat proximal colonic mucosa and released to the gut lumen and subepithelial space. Despite much data regarding its expression and function, the effects of luminal 5-HT on colonic anion secretion have not been fully investigated. EXPERIMENTAL APPROACH We measured short-circuit current (Isc ) as an indicator of ion transport in mucosa-submucosa or mucosa-only preparations of rat proximal colon. Total CO2 output was measured in vitro and in vivo. Immunohistochemistry was performed to investigate the localization of 5-HT4 , NOS1 and NOS2. KEY RESULTS Luminal 5-HT gradually increased the amplitude and sustained the elevation of Isc . Luminal 5-HT-evoked ΔIsc was acetazolamide sensitive and HCO3 (-) dependent, consistent with cytosolic carbonic anhydrase-dependent electrogenic HCO3 (-) secretion, while not affected by tetrodotoxin (TTX), atropine or indomethacin. Pretreatment with the selective 5-HT4 antagonist GR113808, but not antagonists for 5-HT3 , 5-HT6 or 5-HT7 , inhibited luminal 5-HT-evoked ΔIsc . Furthermore, luminal cisapride and tegaserod increased Isc to the same extent as did 5-HT in the presence of indomethacin and TTX. Removal of the submucosa or pretreatment with NOS inhibitors enhanced luminal 5-HT-evoked ΔIsc , suggesting that NO synthesized in the submucosa suppresses mucosal anion secretion. NOS1 and NOS2 were immunostained in the submucosal neurons and glial cells respectively. Luminal 5-HT-evoked HCO3 (-) secretion was confirmed in vivo, inhibited by co-perfusion of GR113808, but not by ondansetron. CONCLUSIONS AND IMPLICATIONS A novel apical 5-HT4 -mediated HCO3 (-) secretory pathway and an NO-dependent inhibitory mechanism are present in the proximal colon. Luminal 5-HT-evoked HCO3 (-) secretion may be important for the maintenance of mucosal integrity by regulating luminal pH.
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Affiliation(s)
- I Kaji
- Department of Medicine, University of California, Los Angeles, CA, USA.,Brentwood Biomedical Research Institute, Los Angeles, CA, USA
| | - Y Akiba
- Department of Medicine, University of California, Los Angeles, CA, USA.,Brentwood Biomedical Research Institute, Los Angeles, CA, USA.,Greater Los Angeles Veterans Affairs Healthcare System, CA, USA
| | - H Said
- College of Letters and Sciences, University of California, Los Angeles, CA, USA
| | - K Narimatsu
- Department of Medicine, University of California, Los Angeles, CA, USA
| | - J D Kaunitz
- Department of Medicine, University of California, Los Angeles, CA, USA.,Department of Surgery, School of Medicine, University of California, Los Angeles, CA, USA.,Brentwood Biomedical Research Institute, Los Angeles, CA, USA.,Greater Los Angeles Veterans Affairs Healthcare System, CA, USA
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Li P, Bracamontes JR, Manion BD, Mennerick S, Steinbach JH, Evers AS, Akk G. The neurosteroid 5β-pregnan-3α-ol-20-one enhances actions of etomidate as a positive allosteric modulator of α1β2γ2L GABAA receptors. Br J Pharmacol 2015; 171:5446-57. [PMID: 25117207 DOI: 10.1111/bph.12861] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 07/11/2014] [Accepted: 07/20/2014] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE Neurosteroids potentiate responses of the GABAA receptor to the endogenous agonist GABA. Here, we examined the ability of neurosteroids to potentiate responses to the allosteric activators etomidate, pentobarbital and propofol. EXPERIMENTAL APPROACH Electrophysiological assays were conducted on rat α1β2γ2L GABAA receptors expressed in HEK 293 cells. The sedative activity of etomidate was studied in Xenopus tadpoles and mice. Effects of neurosteroids on etomidate-elicited inhibition of cortisol synthesis were determined in human adrenocortical cells. KEY RESULTS The neurosteroid 5β-pregnan-3α-ol-20-one (3α5βP) potentiated activation of GABAA receptors by GABA and allosteric activators. Co-application of 1 μM 3α5βP induced a leftward shift (almost 100-fold) of the whole-cell macroscopic concentration-response relationship for gating by etomidate. Co-application of 100 nM 3α5βP reduced the EC50 for potentiation by etomidate of currents elicited by 0.5 μM GABA by about three-fold. In vivo, 3α5βP (1mg kg(-1) ) reduced the dose of etomidate required to produce loss of righting in mice (ED50 ) by almost 10-fold. In tadpoles, the presence of 50 or 100 nM 3α5βP shifted the EC50 for loss of righting about three- or ten-fold respectively. Exposure to 3α5βP did not influence inhibition of cortisol synthesis by etomidate. CONCLUSIONS AND IMPLICATIONS Potentiating neurosteroids act similarly on orthosterically and allosterically activated GABAA receptors. Co-application of neurosteroids with etomidate can significantly reduce dosage requirements for the anaesthetic, and is a potentially beneficial combination to reduce undesired side effects.
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Affiliation(s)
- P Li
- Department of Anesthesiology, Washington University School of Medicine, St Louis, MO, USA
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de Queiroz DB, Sastre E, Caracuel L, Callejo M, Xavier FE, Blanco-Rivero J, Balfagón G. Alterations in perivascular innervation function in mesenteric arteries from offspring of diabetic rats. Br J Pharmacol 2015; 172:4699-713. [PMID: 26177571 DOI: 10.1111/bph.13244] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 06/23/2015] [Accepted: 06/30/2015] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE We have reported that exposure to a diabetic intrauterine environment during pregnancy increases blood pressure in adult offspring, but the mechanisms involved are not completely understood. This study was designed to analyse a possible role of perivascular sympathetic and nitrergic innervation in the superior mesenteric artery (SMA) in this effect. EXPERIMENTAL APPROACH Diabetes was induced in pregnant Wistar rats by a single injection of streptozotocin. Endothelium-denuded vascular rings from the offspring of control (O-CR) and diabetic rats (O-DR) were used. Vasomotor responses to electrical field stimulation (EFS), NA and the NO donor DEA-NO were studied. The expressions of neuronal NOS (nNOS) and phospho-nNOS (P-nNOS) and release of NA, ATP and NO were determined. Sympathetic and nitrergic nerve densities were analysed by immunofluorescence. KEY RESULTS Blood pressure was higher in O-DR animals. EFS-induced vasoconstriction was greater in O-DR animals. This response was decreased by phentolamine more in O-DR animals than their controls. L-NAME increased EFS-induced vasoconstriction more strongly in O-DR than in O-CR segments. Vasomotor responses to NA or DEA-NO were not modified. NA, ATP and NO release was increased in segments from O-DR. nNOS expression was not modified, whereas P-nNOS expression was increased in O-DR. Sympathetic and nitrergic nerve densities were similar in both experimental groups. CONCLUSIONS AND IMPLICATIONS The activity of sympathetic and nitrergic innervation is increased in SMA from O-DR animals. The net effect is an increase in EFS-induced contractions in these animals. These effects may contribute to the increased blood pressure observed in the offspring of diabetic rats.
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Affiliation(s)
- D B de Queiroz
- Departamento de Fisiologia e Farmacologia, Universidade Federal de Pernambuco, Recife, Brazil
| | - E Sastre
- Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación La Paz (IdIPAZ), Madrid, Spain
| | - L Caracuel
- Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación La Paz (IdIPAZ), Madrid, Spain
| | - M Callejo
- Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - F E Xavier
- Departamento de Fisiologia e Farmacologia, Universidade Federal de Pernambuco, Recife, Brazil
| | - J Blanco-Rivero
- Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación La Paz (IdIPAZ), Madrid, Spain
| | - G Balfagón
- Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación La Paz (IdIPAZ), Madrid, Spain
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Singh NS, Bernier M, Camandola S, Khadeer MA, Moaddel R, Mattson MP, Wainer IW. Enantioselective inhibition of d-serine transport by (S)-ketamine. Br J Pharmacol 2015; 172:4546-4559. [PMID: 26140427 DOI: 10.1111/bph.13239] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 06/26/2015] [Accepted: 06/28/2015] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND AND PURPOSE Patients with major depressive disorder receiving racemic ketamine, (R,S)-ketamine, experience transient increases in Clinician-Administered Dissociative States Scale scores and a coincident drop in plasma d-serine levels. The results suggest that (R,S)-ketamine produces an immediate, concentration-dependent pharmacological effect on d-serine plasma concentrations. One potential source of this effect is (R,S)-ketamine-induced inhibition of the transporter ASCT2, which regulates intracellular d-serine concentrations. In this study, we tested this hypothesis by examining the effect of (S)- and (R)-ketamine on ASCT2-mediated transport of d-serine in PC-12 and 1321N1 cells and primary neuronal cells in culture. EXPERIMENTAL APPROACH Intracellular and extracellular d-serine levels were determined using capillary electrophoresis-laser-induced fluorescence and liquid chromatography-mass spectrometry respectively. Expression of ASCT2, Asc-1 and serine racemase was determined utilizing Western blotting. KEY RESULTS (S)-Ketamine produced a concentration-dependent increase in intracellular d-serine and reduced extracellular d-serine accumulation. In contrast, (R)-ketamine decreased both intracellular and extracellular d-serine levels. The ASCT2 inhibitor, benzyl-d-serine (BDS), and ASCT2 gene knockdown mimicked the action of (S)-ketamine on d-serine in PC-12 cells, while the Asc-1 agonist d-isoleucine reduced intracellular d-serine and increased extracellular d-serine accumulation. This response to d-isoleucine was not affected by BDS or (S)-ketamine. Primary cultures of rat neuronal cells expressed ASCT2 and were responsive to (S)-ketamine and BDS. (S)- and (R)-ketamine increased the expression of monomeric serine racemase in all the cells studied, with (S)-ketamine having the greatest effect. CONCLUSIONS AND IMPLICATIONS (S)-Ketamine decreased cellular export of d-serine via selective inhibition of ASCT2, and this could represent a possible source of dissociative effects observed with (R,S)-ketamine.
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Affiliation(s)
- Nagendra S Singh
- Laboratory of Clinical Investigation, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Michel Bernier
- Translational Gerontology Branch, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Simonetta Camandola
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Mohammed A Khadeer
- Laboratory of Clinical Investigation, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Ruin Moaddel
- Laboratory of Clinical Investigation, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Irving W Wainer
- Laboratory of Clinical Investigation, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
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Takatori S, Hirai K, Ozaki S, Tangsucharit P, Fukushima-Miyashita S, Goda M, Hashikawa-Hobara N, Ono N, Kawasaki H. Protons modulate perivascular axo-axonal neurotransmission in the rat mesenteric artery. Br J Pharmacol 2015; 171:5743-56. [PMID: 25117291 DOI: 10.1111/bph.12878] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 07/07/2014] [Accepted: 08/01/2014] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND AND PURPOSE Previous studies have demonstrated that nicotine releases protons from adrenergic nerves via stimulation of nicotinic ACh receptors and activates transient receptor potential vanilloid-1 (TRPV1) receptors located on calcitonin gene-related peptide (CGRP)-containing (CGRPergic) vasodilator nerves, resulting in vasodilatation. The present study investigated whether perivascular nerves release protons, which modulate axon-axonal neurotransmission. EXPERIMENT APPROACH Perfusion pressure and pH levels of perfusate in rat-perfused mesenteric vascular beds without endothelium were measured with a pressure transducer and a pH meter respectively. KEY RESULTS Periarterial nerve stimulation (PNS) initially induced vasoconstriction, which was followed by long-lasting vasodilatation and decreased pH levels in the perfusate. Cold-storage denervation of the preparation abolished the decreased pH and vascular responses to PNS. The adrenergic neuron blocker guanethidine inhibited PNS-induced vasoconstriction and effects on pH, but not PNS-induced vasodilatation. Capsaicin (CGRP depletor), capsazepine and ruthenium red (TRPV1 inhibitors) attenuated the PNS-induced decrease in pH and vasodilatation. In denuded preparations, ACh caused long-lasting vasodilatation and lowered pH; these effects were inhibited by capsaicin pretreatment and atropine, but not by guanethidine or mecamylamine. Capsaicin injection induced vasodilatation and a reduction in pH, which were abolished by ruthenium red. The use of a fluorescent pH indicator demonstrated that application of nicotine, ACh and capsaicin outside small mesenteric arteries reduced perivascular pH levels and these effects were abolished in a Ca(2+) -free medium. CONCLUSION AND IMPLICATION These results suggest that protons are released from perivascular adrenergic and CGRPergic nerves upon PNS and these protons modulate transmission in CGRPergic nerves.
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Affiliation(s)
- Shingo Takatori
- Department of Clinical Pharmacy, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime, Japan; Department of Clinical Pharmaceutical Science, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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Eckle VS, Grasshoff C, Mirakaj V, O'Neill PM, Berry NG, Leuwer M, Antkowiak B. 4-bromopropofol decreases action potential generation in spinal neurons by inducing a glycine receptor-mediated tonic conductance. Br J Pharmacol 2015; 171:5790-801. [PMID: 25131750 DOI: 10.1111/bph.12880] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 07/29/2014] [Accepted: 08/11/2014] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Impaired function of spinal strychnine-sensitive glycine receptors gives rise to chronic pain states and movement disorders. Therefore, increased activity of glycine receptors should help to treat such disorders. Although compounds targeting glycine receptors with a high selectivity are lacking, halogenated analogues of propofol have recently been considered as potential candidates. Therefore we asked whether 4-bromopropofol attenuated the excitability of spinal neurons by promoting glycine receptor-dependent inhibition. EXPERIMENTAL APPROACH The actions of sub-anaesthetic concentrations of propofol and 4-bromopropofol were investigated in spinal tissue cultures prepared from mice. Drug-induced alterations in action potential firing were monitored by extracellular multi-unit recordings. The effects on GABAA and glycine receptor-mediated inhibition were quantified by whole-cell voltage-clamp recordings. KEY RESULTS Low concentrations of 4-bromopropofol (50 nM) reduced action potential activity of ventral horn neurons by about 30%, compared with sham-treated slices. This effect was completely abolished by strychnine (1 μM). In voltage-clamped neurons, 4-bromopropofol activated glycine receptors, generating a tonic current of 65 ± 10 pA, while GABAA - and glycine receptor-mediated synaptic transmission remained unaffected. CONCLUSIONS AND IMPLICATIONS The highest glycine levels in the CNS are found in the ventral horn of the spinal cord, a region mediating pain-induced motor reflexes and participating in the control of muscle tone. 4-Bromopropofol may serve as a starting point for the development of non-sedative, non-addictive, muscle relaxants and analgesics to be used to treat low back pain.
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Affiliation(s)
- V S Eckle
- Experimental Anaesthesiology Section, Department of Anaesthesiology and Intensive Care, Eberhard-Karls-University, Tübingen, Germany
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Krishnan SM, Sobey CG, Latz E, Mansell A, Drummond GR. IL-1β and IL-18: inflammatory markers or mediators of hypertension? Br J Pharmacol 2015; 171:5589-602. [PMID: 25117218 PMCID: PMC4290704 DOI: 10.1111/bph.12876] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/30/2014] [Accepted: 08/06/2014] [Indexed: 12/11/2022] Open
Abstract
Chronic inflammation in the kidneys and vascular wall is a major contributor to hypertension. However, the stimuli and cellular mechanisms responsible for such inflammatory responses remain poorly defined. Inflammasomes are crucial initiators of sterile inflammation in other diseases such as rheumatoid arthritis and gout. These pattern recognition receptors detect host-derived danger-associated molecular patterns (DAMPs), such as microcrystals and reactive oxygen species, and respond by inducing activation of caspase-1. Caspase-1 then processes the cytokines pro-IL-1β and pro-IL-18 into their active forms thus triggering inflammation. While IL-1β and IL-18 are known to be elevated in hypertensive patients, no studies have examined whether this occurs downstream of inflammasome activation or whether inhibition of inflammasome and/or IL-1β/IL-18 signalling prevents hypertension. In this review, we will discuss some known actions of IL-1β and IL-18 on leukocyte and vessel wall function that could potentially underlie a prohypertensive role for these cytokines. We will describe the major classes of inflammasome-activating DAMPs and present evidence that at least some of these are elevated in the setting of hypertension. Finally, we will provide information on drugs that are currently used to inhibit inflammasome/IL-1β/IL-18 signalling and how these might ultimately be used as therapeutic agents for the clinical management of hypertension.
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Affiliation(s)
- S M Krishnan
- Department of Pharmacology, Monash University, Clayton, Vic, Australia
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Lodge D, Mercier MS. Ketamine and phencyclidine: the good, the bad and the unexpected. Br J Pharmacol 2015; 172:4254-76. [PMID: 26075331 DOI: 10.1111/bph.13222] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 05/29/2015] [Accepted: 06/03/2015] [Indexed: 12/21/2022] Open
Abstract
The history of ketamine and phencyclidine from their development as potential clinical anaesthetics through drugs of abuse and animal models of schizophrenia to potential rapidly acting antidepressants is reviewed. The discovery in 1983 of the NMDA receptor antagonist property of ketamine and phencyclidine was a key step to understanding their pharmacology, including their psychotomimetic effects in man. This review describes the historical context and the course of that discovery and its expansion into other hallucinatory drugs. The relevance of these findings to modern hypotheses of schizophrenia and the implications for drug discovery are reviewed. The findings of the rapidly acting antidepressant effects of ketamine in man are discussed in relation to other glutamatergic mechanisms.
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Affiliation(s)
- D Lodge
- Centre for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, Bristol, UK
| | - M S Mercier
- Centre for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, Bristol, UK
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Lee AM, Wu DF, Dadgar J, Wang D, McMahon T, Messing RO. PKCε phosphorylates α4β2 nicotinic ACh receptors and promotes recovery from desensitization. Br J Pharmacol 2015; 172:4430-41. [PMID: 26103136 DOI: 10.1111/bph.13228] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 06/10/2015] [Accepted: 06/13/2015] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE Nicotinic (ACh) receptor recovery from desensitization is modulated by PKC, but the PKC isozymes and the phosphorylation sites involved have not been identified. We investigated whether PKCε phosphorylation of α4β2 nAChRs regulates receptor recovery from desensitization. EXPERIMENTAL APPROACH Receptor recovery from desensitization was investigated by electrophysiological characterization of human α4β2 nAChRs. Phosphorylation of the α4 nAChR subunit was assessed by immunoblotting of mouse synaptosomes. Hypothermia induced by sazetidine-A and nicotine was measured in Prkce(-/-) and wild-type mice. KEY RESULTS Inhibiting PKCε impaired the magnitude of α4β2 nAChR recovery from desensitization. We identified five putative PKCε phosphorylation sites in the large intracellular loop of the α4 subunit, and mutating four sites to alanines also impaired recovery from desensitization. α4 nAChR subunit phosphorylation was reduced in synaptosomes from Prkce(-/-) mice. Sazetidine-A-induced hypothermia, which is mediated by α4β2 nAChR desensitization, was more severe and prolonged in Prkce(-/-) than in wild-type mice. CONCLUSIONS AND IMPLICATIONS PKCε phosphorylates the α4 nAChR subunit and regulates recovery from receptor desensitization. This study illustrates the importance of phosphorylation in regulating α4β2 receptor function, and suggests that reducing phosphorylation prolongs receptor desensitization and decreases the number of receptors available for activation.
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Affiliation(s)
- A M Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
| | - D-F Wu
- Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX, USA
| | - J Dadgar
- Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX, USA
| | - D Wang
- Ernest Gallo Clinic and Research Center, University of California at San Francisco, Emeryville, CA, USA
| | - T McMahon
- Ernest Gallo Clinic and Research Center, University of California at San Francisco, Emeryville, CA, USA
| | - R O Messing
- Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin, Austin, TX, USA
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Prenderville JA, Kelly ÁM, Downer EJ. The role of cannabinoids in adult neurogenesis. Br J Pharmacol 2015; 172:3950-63. [PMID: 25951750 DOI: 10.1111/bph.13186] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 04/17/2015] [Accepted: 04/22/2015] [Indexed: 12/17/2022] Open
Abstract
The processes underpinning post-developmental neurogenesis in the mammalian brain continue to be defined. Such processes involve the proliferation of neural stem cells and neural progenitor cells (NPCs), neuronal migration, differentiation and integration into a network of functional synapses within the brain. Both intrinsic (cell signalling cascades) and extrinsic (neurotrophins, neurotransmitters, cytokines, hormones) signalling molecules are intimately associated with adult neurogenesis and largely dictate the proliferative activity and differentiation capacity of neural cells. Cannabinoids are a unique class of chemical compounds incorporating plant-derived cannabinoids (the active components of Cannabis sativa), the endogenous cannabinoids and synthetic cannabinoid ligands, and these compounds are becoming increasingly recognized for their roles in neural developmental processes. Indeed, cannabinoids have clear modulatory roles in adult neurogenesis, probably through activation of both CB1 and CB2 receptors. In recent years, a large body of literature has deciphered the signalling networks involved in cannabinoid-mediated regulation of neurogenesis. This timely review summarizes the evidence that the cannabinoid system is intricately associated with neuronal differentiation and maturation of NPCs and highlights intrinsic/extrinsic signalling mechanisms that are cannabinoid targets. Overall, these findings identify the central role of the cannabinoid system in adult neurogenesis in the hippocampus and the lateral ventricles and hence provide insight into the processes underlying post-developmental neurogenesis in the mammalian brain.
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Affiliation(s)
- Jack A Prenderville
- Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland.,Trinity College Institute of Neuroscience, University of Dublin, Trinity College, Dublin, Ireland
| | - Áine M Kelly
- Department of Physiology, School of Medicine, Trinity College, Dublin, Ireland.,Trinity College Institute of Neuroscience, University of Dublin, Trinity College, Dublin, Ireland
| | - Eric J Downer
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
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Lu XZ, Bi XY, He X, Zhao M, Xu M, Yu XJ, Zhao ZH, Zang WJ. Activation of M3 cholinoceptors attenuates vascular injury after ischaemia/reperfusion by inhibiting the Ca2+/calmodulin-dependent protein kinase II pathway. Br J Pharmacol 2015; 172:5619-33. [PMID: 25953628 DOI: 10.1111/bph.13183] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 03/24/2015] [Accepted: 04/20/2015] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE The activation of M3 cholinoceptors (M3 receptors) by choline reduces cardiovascular risk, but it is unclear whether these receptors can regulate ischaemia/reperfusion (I/R)-induced vascular injury. Thus, the primary goal of the present study was to explore the effects of choline on the function of mesenteric arteries following I/R, with a major focus on Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) regulation. EXPERIMENTAL APPROACH Rats were given choline (10 mg · kg(-1), i.v.) and then the superior mesenteric artery was occluded for 60 min (ischaemia), followed by 90 min of reperfusion. The M3 receptor antagonist, 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP), was injected (0.12 μg · kg(-1), i.v.) 5 min prior to choline treatment. Vascular function was examined in rings of mesenteric arteries isolated after the reperfusion procedure. Vascular superoxide anion production, CaMKII and the levels of Ca(2+)-cycling proteins were also assessed. KEY RESULTS Choline treatment attenuated I/R-induced vascular dysfunction, blocked elevations in the levels of reactive oxygen species (ROS) and decreased the up-regulated expression of oxidised CaMKII and phosphorylated CaMKII. In addition, choline reversed the abnormal expression of Ca(2+)-cycling proteins, including Na(+)Ca(2+) exchanger, inositol 1,4,5-trisphosphate receptor, sarcoplasmic reticulum Ca(2+)-ATPase and phospholamban. All of these cholinergic effects of choline were abolished by 4-DAMP. CONCLUSIONS AND IMPLICATIONS Our data suggest that inhibition of the ROS-mediated CaMKII pathway and modulation of Ca(2+)-cycling proteins may be novel mechanisms underlying choline-induced vascular protection. These results represent a significant addition to the understanding of the pharmacological roles of M3 receptors in the vasculature, providing a new therapeutic strategy for I/R-induced vascular injury.
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Affiliation(s)
- Xing-Zhu Lu
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Xue-Yuan Bi
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Xi He
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Ming Zhao
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Man Xu
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Xiao-Jiang Yu
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Zheng-Hang Zhao
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Wei-Jin Zang
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an, China
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47
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Ramachandran R, Yaksh TL. Therapeutic use of botulinum toxin in migraine: mechanisms of action. Br J Pharmacol 2015; 171:4177-92. [PMID: 24819339 DOI: 10.1111/bph.12763] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 04/25/2014] [Accepted: 05/02/2014] [Indexed: 12/30/2022] Open
Abstract
Migraine pain represents sensations arising from the activation of trigeminal afferents, which innervate the meningeal vasculature and project to the trigeminal nucleus caudalis (TNC). Pain secondary to meningeal input is referred to extracranial regions innervated by somatic afferents that project to homologous regions in the TNC. Such viscerosomatic convergence accounts for referral of migraine pain arising from meningeal afferents to particular extracranial dermatomes. Botulinum toxins (BoNTs) delivered into extracranial dermatomes are effective in and approved for treating chronic migraine pain. Aside from their well-described effect upon motor endplates, BoNTs are also taken up in local afferent nerve terminals where they cleave soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, and prevent local terminal release. However, a local extracranial effect of BoNT cannot account for allthe effects of BoNT upon migraine. We now know that peripherally delivered BoNTs are taken up in sensory afferents and transported to cleave SNARE proteins in the ganglion and TNC, prevent evoked afferent release and downstream activation. Such effects upon somatic input (as from the face) likewise would not alone account for block of input from converging meningeal afferents. This current work suggests that BoNTs may undergo transcytosis to cleave SNAREs in second-order neurons or in adjacent afferent terminals. Finally, while SNAREs mediate exocytotic release, they are also involved in transport of channels and receptors involved in facilitated pain states. The role of such post-synaptic effects of BoNT action in migraine remains to be determined.
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Affiliation(s)
- Roshni Ramachandran
- Anesthesiology Research, Department of Anesthesiology, University of California, San Diego, La Jolla, CA, USA
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48
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Kaji MD, Kwaka A, Callanan MK, Nusrat H, Desaulniers JP, Forrester SG. A molecular characterization of the agonist binding site of a nematode cys-loop GABA receptor. Br J Pharmacol 2015; 172:3737-47. [PMID: 25850584 DOI: 10.1111/bph.13158] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 03/30/2015] [Accepted: 03/31/2015] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Cys-loop GABA receptors represent important targets for human chemotherapeutics and insecticides and are potential targets for novel anthelmintics (nematicides). However, compared with insect and mammalian receptors, little is known regarding the pharmacological characteristics of nematode Cys-loop GABA receptors. Here we have investigated the agonist binding site of the Cys-loop GABA receptor UNC-49 (Hco-UNC-49) from the parasitic nematode Haemonchus contortus. EXPERIMENTAL APPROACH We used two-electrode voltage-clamp electrophysiology to measure channel activation by classical GABA receptor agonists on Hco-UNC-49 expressed in Xenopus laevis oocytes, along with site-directed mutagenesis and in silico homology modelling. KEY RESULTS The sulphonated molecules P4S and taurine had no effect on Hco-UNC-49. Other classical Cys-loop GABAA receptor agonists tested on the Hco-UNC-49B/C heteromeric channel had a rank order efficacy of GABA > trans-4-aminocrotonic acid > isoguvacine > imidazole-4-acetic acid (IMA) > (R)-(-)-4-amino-3-hydroxybutyric acid [R(-)-GABOB] > (S)-(+)-4-amino-3-hydroxybutyric acid [S(+)-GABOB] > guanidinoacetic acid > isonipecotic acid > 5-aminovaleric acid (DAVA) (partial agonist) > β-alanine (partial agonist). In silico ligand docking revealed some variation in binding between agonists. Mutagenesis of a key serine residue in binding loop C to threonine had minimal effects on GABA and IMA but significantly increased the maximal response to DAVA and decreased twofold the EC50 for R(-)- and S(+)-GABOB. CONCLUSIONS AND IMPLICATIONS The pharmacological profile of Hco-UNC-49 differed from that of vertebrate Cys-loop GABA receptors and insect resistance to dieldrin receptors, suggesting differences in the agonist binding pocket. These findings could be exploited to develop new drugs that specifically target GABA receptors of parasitic nematodes.
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Affiliation(s)
- Mark D Kaji
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, ON, Canada
| | - Ariel Kwaka
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, ON, Canada
| | - Micah K Callanan
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, ON, Canada
| | - Humza Nusrat
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, ON, Canada
| | - Jean-Paul Desaulniers
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, ON, Canada
| | - Sean G Forrester
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, ON, Canada
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49
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Corrigan F, Vink R, Turner RJ. Inflammation in acute CNS injury: a focus on the role of substance P. Br J Pharmacol 2015; 173:703-15. [PMID: 25827155 DOI: 10.1111/bph.13155] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 03/02/2015] [Accepted: 03/24/2015] [Indexed: 12/13/2022] Open
Abstract
Recently, a number of reports have shown that neurogenic inflammation may play a role in the secondary injury response following acute injury to the CNS, including traumatic brain injury (TBI) and stroke. In particular substance P (SP) release appears to be critically involved. Specifically, the expression of the neuropeptide SP is increased in acute CNS injury, with the magnitude of SP release being related to both the frequency and magnitude of the insult. SP release is associated with an increase in blood-brain barrier permeability and the development of vasogenic oedema as well as neuronal injury and worse functional outcome. Moreover, inhibiting the actions of SP through use of a NK1 receptor antagonist is highly beneficial in both focal and diffuse models of TBI, as well as in ischaemic stroke, with a therapeutic window of up to 12 h. We propose that NK1 receptor antagonists represent a novel therapeutic option for treatment of neurogenic inflammation following acute CNS injury.
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Affiliation(s)
- F Corrigan
- Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
| | - R Vink
- Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - R J Turner
- Adelaide Centre for Neuroscience Research, The University of Adelaide, Adelaide, SA, Australia
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50
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Dixon CL, Harrison NL, Lynch JW, Keramidas A. Zolpidem and eszopiclone prime α1β2γ2 GABAA receptors for longer duration of activity. Br J Pharmacol 2015; 172:3522-36. [PMID: 25817320 DOI: 10.1111/bph.13142] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 02/23/2015] [Accepted: 03/22/2015] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND AND PURPOSE GABAA receptors mediate neuronal inhibition in the brain. They are the primary targets for benzodiazepines, which are widely used to treat neurological disorders including anxiety, epilepsy and insomnia. The mechanism by which benzodiazepines enhance GABAA receptor activity has been extensively studied, but there is little mechanistic information on how non-benzodiazepine drugs that bind to the same site exert their effects. Eszopiclone and zolpidem are two non-benzodiazepine drugs for which no mechanism of action has yet been proposed, despite their clinical importance as sleeping aids. Here we investigate how both drugs enhance the activity of α1β2γ2 GABAA receptors. EXPERIMENTAL APPROACH We used rapid ligand application onto macropatches and single-channel kinetic analysis to assess rates of current deactivation. We also studied synaptic currents in primary neuronal cultures and in heterosynapses, whereby native GABAergic nerve terminals form synapses with HEK293 cells expressing α1β2γ2 GABAA receptors. Drug binding and modulation was quantified with the aid of an activation mechanism. KEY RESULTS At the single-channel level, the drugs prolonged the duration of receptor activation, with similar KD values of ∼80 nM. Channel activation was prolonged primarily by increasing the equilibrium constant between two connected shut states that precede channel opening. CONCLUSIONS AND IMPLICATIONS As the derived mechanism successfully simulated the effects of eszopiclone and zolpidem on ensemble currents, we propose it as the definitive mechanism accounting for the effects of both drugs. Importantly, eszopiclone and zolpidem enhanced GABAA receptor currents via a mechanism that differs from that proposed for benzodiazepines.
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Affiliation(s)
- Christine L Dixon
- Queensland Brain Institute, University of Queensland, Brisbane, Qld, Australia
| | - Neil L Harrison
- Department of Anesthesiology and Department of Pharmacology, Columbia University, New York, NY, USA
| | - Joseph W Lynch
- Queensland Brain Institute, University of Queensland, Brisbane, Qld, Australia.,School of Biomedical Sciences, University of Queensland, Brisbane, Qld, Australia
| | - Angelo Keramidas
- Queensland Brain Institute, University of Queensland, Brisbane, Qld, Australia.,Department of Anesthesiology and Department of Pharmacology, Columbia University, New York, NY, USA
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