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Bönisch H, Fink KB, Malinowska B, Molderings GJ, Schlicker E. Serotonin and beyond-a tribute to Manfred Göthert (1939-2019). NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2021; 394:1829-1867. [PMID: 33991216 PMCID: PMC8376721 DOI: 10.1007/s00210-021-02083-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 03/29/2021] [Indexed: 01/13/2023]
Abstract
Manfred Göthert, who had served Naunyn-Schmiedeberg's Arch Pharmacol as Managing Editor from 1998 to 2005, deceased in June 2019. His scientific oeuvre encompasses more than 20 types of presynaptic receptors, mostly on serotoninergic and noradrenergic neurones. He was the first to identify presynaptic receptors for somatostatin and ACTH and described many presynaptic receptors, known from animal preparations, also in human tissue. In particular, he elucidated the pharmacology of presynaptic 5-HT receptors. A second field of interest included ligand-gated and voltage-dependent channels. The negative allosteric effect of anesthetics at peripheral nACh receptors is relevant for the peripheral clinical effects of these drugs and modified the Meyer-Overton hypothesis. The negative allosteric effect of ethanol at NMDA receptors in human brain tissue occurred at concentrations found in the range of clinical ethanol intoxication. Moreover, the inhibitory effect of gabapentinoids on P/Q Ca2+ channels and the subsequent decrease in AMPA-induced noradrenaline release may contribute to their clinical effect. Another ligand-gated ion channel, the 5-HT3 receptor, attracted the interest of Manfred Göthert from the whole animal via isolated preparations down to the cellular level. He contributed to that molecular study in which 5-HT3 receptor subtypes were disclosed. Finally, he found altered pharmacological properties of 5-HT receptor variants like the Arg219Leu 5-HT1A receptor (which was also shown to be associated with major depression) and the Phe124Cys 5-HT1B receptor (which may be related to sumatriptan-induced vasospasm). Manfred Göthert was a brilliant scientist and his papers have a major impact on today's pharmacology.
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Affiliation(s)
- H Bönisch
- Institute of Pharmacology and Toxicology, University of Bonn, Venusberg-Campus 1, 53105, Bonn, Germany
| | - K B Fink
- Merz Pharmaceuticals, Frankfurt/Main, Germany
| | - B Malinowska
- Department of Physiology and Pathophysiology, Medical University of Białystok, Białystok, Poland
| | - G J Molderings
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - E Schlicker
- Institute of Pharmacology and Toxicology, University of Bonn, Venusberg-Campus 1, 53105, Bonn, Germany.
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2
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Kim J, Kim SH, Kang H, Lee S, Park SY, Cho Y, Lim YM, Ahn JW, Kim YH, Chung S, Choi CS, Jang YJ, Park HS, Heo Y, Kim KH, Lee MS. TFEB-GDF15 axis protects against obesity and insulin resistance as a lysosomal stress response. Nat Metab 2021; 3:410-427. [PMID: 33758420 DOI: 10.1038/s42255-021-00368-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/18/2021] [Indexed: 01/01/2023]
Abstract
TFEB, a key regulator of lysosomal biogenesis and autophagy, is induced not only by nutritional deficiency but also by organelle stress. Here, we find that Tfeb and its downstream genes are upregulated together with lipofuscin accumulation in adipose tissue macrophages (ATMs) of obese mice or humans, suggestive of obesity-associated lysosomal dysfunction/stress in ATMs. Macrophage-specific TFEB-overexpressing mice display complete abrogation of diet-induced obesity, adipose tissue inflammation and insulin resistance, which is independent of autophagy, but dependent on TFEB-induced GDF15 expression. Palmitic acid induces Gdf15 expression through lysosomal Ca2+-mediated TFEB nuclear translocation in response to lysosomal stress. In contrast, mice fed a high-fat diet with macrophage-specific Tfeb deletion show aggravated adipose tissue inflammation and insulin resistance, accompanied by reduced GDF15 level. Finally, we observe activation of TFEB-GDF15 in ATMs of obese humans as a consequence of lysosomal stress. These findings highlight the importance of the TFEB-GDF15 axis as a lysosomal stress response in obesity or metabolic syndrome and as a promising therapeutic target for treatment of these conditions.
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Affiliation(s)
- Jinyoung Kim
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Seong Hun Kim
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
- Discovery 1 team, GI Innovation, Seoul, Korea
| | - Hyereen Kang
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Soyeon Lee
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Shi-Young Park
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University College of Medicine, Incheon, Korea
| | - Yoonil Cho
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University College of Medicine, Incheon, Korea
| | - Yu-Mi Lim
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Ji Woong Ahn
- Brain Korea 21 Project for Medical Science, Department of Physiology, Yonsei University College of Medicine, Seoul, Korea
| | - Young-Hwan Kim
- Brain Korea 21 Project for Medical Science, Department of Physiology, Yonsei University College of Medicine, Seoul, Korea
| | - Seungsoo Chung
- Brain Korea 21 Project for Medical Science, Department of Physiology, Yonsei University College of Medicine, Seoul, Korea
| | - Cheol Soo Choi
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University College of Medicine, Incheon, Korea
- Endocrinology, Internal Medicine, Gachon University Gil Medical Center, Incheon, Korea
| | - Yeon Jin Jang
- Department of Physiology, University of Ulsan College of Medicine, Seoul, Korea
| | - Hye Soon Park
- Department of Family Medicine, University of Ulsan College of Medicine, Seoul, Korea
| | - Yoonseok Heo
- Department of General Surgery, Inha University, College of Medicine, Incheon, Korea
| | - Kook Hwan Kim
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea.
- Discovery 1 team, GI Innovation, Seoul, Korea.
| | - Myung-Shik Lee
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea.
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
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3
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Kitano T, Kobayashi T, Yamaguchi S, Otsuguro KI. The α 2A -adrenoceptor subtype plays a key role in the analgesic and sedative effects of xylazine. J Vet Pharmacol Ther 2018; 42:243-247. [PMID: 30417462 DOI: 10.1111/jvp.12724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 09/04/2018] [Accepted: 09/05/2018] [Indexed: 11/27/2022]
Abstract
Xylazine, the classical α2 -adrenoceptor (α2 -AR) agonist, is still used as an analgesic and sedative in veterinary medicine, despite its low potency and affinity for α2 -ARs. Previous pharmacological studies suggested that the α2A -AR subtype plays a role in mediating the clinical effects of xylazine; however, these studies were hampered by the poor subtype-selectivity of the antagonists used and a lack of knowledge of their bioavailability in vivo. Here, we attempted to elucidate the role of the α2A -AR subtype in mediating the clinical effects of xylazine by comparing the analgesic and sedative effects of this drug in wild-type mice with those in α2A -AR functional knockout mice using the hot-plate and open field tests, respectively. Hippocampal noradrenaline turnover in both mice was also measured to evaluate the contribution of α2A -AR subtype to the inhibitory effect of xylazine on presynaptic noradrenaline release. In wild-type mice, xylazine (10 or 30 mg/kg) increased the hot-plate latency. Furthermore, xylazine (3 or 10 mg/kg) inhibited the open field locomotor activity and decreased hippocampal noradrenaline turnover. By contrast, all of these effects were abolished in α2A -AR functional knockout mice. These results indicate that the α2A -AR subtype is mainly responsible for the clinical effects of xylazine.
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Affiliation(s)
- Taisuke Kitano
- Laboratory of Pharmacology, Department of Basic Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Takeshi Kobayashi
- Laboratory of Pharmacology, Department of Basic Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Soichiro Yamaguchi
- Laboratory of Pharmacology, Department of Basic Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Ken-Ichi Otsuguro
- Laboratory of Pharmacology, Department of Basic Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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Benítez J, García D, Romero N, González A, Martínez-Oyanedel J, Figueroa M, Salas M, López V, García-Robles M, Dodd PR, Schenk G, Carvajal N, Uribe E. Metabolic strategies for the degradation of the neuromodulator agmatine in mammals. Metabolism 2018; 81:35-44. [PMID: 29162499 DOI: 10.1016/j.metabol.2017.11.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 10/23/2017] [Accepted: 11/08/2017] [Indexed: 01/08/2023]
Abstract
Agmatine (1-amino-4-guanidinobutane), a precursor for polyamine biosynthesis, has been identified as an important neuromodulator with anticonvulsant, antineurotoxic and antidepressant actions in the brain. In this context it has emerged as an important mediator of addiction/satiety pathways associated with alcohol misuse. Consequently, the regulation of the activity of key enzymes in agmatine metabolism is an attractive strategy to combat alcoholism and related addiction disorders. Agmatine results from the decarboxylation of L-arginine in a reaction catalyzed by arginine decarboxylase (ADC), and can be converted to either guanidine butyraldehyde by diamine oxidase (DAO) or putrescine and urea by the enzyme agmatinase (AGM) or the more recently identified AGM-like protein (ALP). In rat brain, agmatine, AGM and ALP are predominantly localised in areas associated with roles in appetitive and craving (drug-reinstatement) behaviors. Thus, inhibitors of AGM or ALP are promising agents for the treatment of addictions. In this review, the properties of DAO, AGM and ALP are discussed with a view to their role in the agmatine metabolism in mammals.
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Affiliation(s)
- José Benítez
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - David García
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Nicol Romero
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Arlette González
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - José Martínez-Oyanedel
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Maximiliano Figueroa
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Mónica Salas
- Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
| | - Vasthi López
- Departamento de Ciencias Biomédicas, Universidad Católica del Norte, Coquimbo, Chile
| | - María García-Robles
- Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Peter R Dodd
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Gerhard Schenk
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Nelson Carvajal
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Elena Uribe
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
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5
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Grzelka K, Kurowski P, Gawlak M, Szulczyk P. Noradrenaline Modulates the Membrane Potential and Holding Current of Medial Prefrontal Cortex Pyramidal Neurons via β 1-Adrenergic Receptors and HCN Channels. Front Cell Neurosci 2017; 11:341. [PMID: 29209170 PMCID: PMC5701640 DOI: 10.3389/fncel.2017.00341] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/16/2017] [Indexed: 12/27/2022] Open
Abstract
The medial prefrontal cortex (mPFC) receives dense noradrenergic projections from the locus coeruleus. Adrenergic innervation of mPFC pyramidal neurons plays an essential role in both physiology (control of memory formation, attention, working memory, and cognitive behavior) and pathophysiology (attention deficit hyperactivity disorder, posttraumatic stress disorder, cognitive deterioration after traumatic brain injury, behavioral changes related to addiction, Alzheimer's disease and depression). The aim of this study was to elucidate the mechanism responsible for adrenergic receptor-mediated control of the resting membrane potential in layer V mPFC pyramidal neurons. The membrane potential or holding current of synaptically isolated layer V mPFC pyramidal neurons was recorded in perforated-patch and classical whole-cell configurations in slices from young rats. Application of noradrenaline (NA), a neurotransmitter with affinity for all types of adrenergic receptors, evoked depolarization or inward current in the tested neurons irrespective of whether the recordings were performed in the perforated-patch or classical whole-cell configuration. The effect of noradrenaline depended on β1- and not α1- or α2-adrenergic receptor stimulation. Activation of β1-adrenergic receptors led to an increase in inward Na+ current through hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which carry a mixed Na+/K+ current. The protein kinase A- and C-, glycogen synthase kinase-3β- and tyrosine kinase-linked signaling pathways were not involved in the signal transduction between β1-adrenergic receptors and HCN channels. The transduction system operated in a membrane-delimited fashion and involved the βγ subunit of G-protein. Thus, noradrenaline controls the resting membrane potential and holding current in mPFC pyramidal neurons through β1-adrenergic receptors, which in turn activate HCN channels via a signaling pathway involving the βγ subunit.
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Affiliation(s)
- Katarzyna Grzelka
- Laboratory of Physiology and Pathophysiology, Centre for Preclinical Research and Technology, Medical University of Warsaw, Warsaw, Poland
| | | | | | - Paweł Szulczyk
- Laboratory of Physiology and Pathophysiology, Centre for Preclinical Research and Technology, Medical University of Warsaw, Warsaw, Poland
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6
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Effects of I 2 -imidazoline receptor (IR) alkylating BU99006 in the mouse brain: Upregulation of nischarin/I 1 -IR and μ-opioid receptor proteins and modulation of associated signalling pathways. Neurochem Int 2017; 108:169-176. [DOI: 10.1016/j.neuint.2017.03.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 03/16/2017] [Accepted: 03/21/2017] [Indexed: 12/12/2022]
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7
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Kim YH, Jeong JH, Ahn DS, Chung S. Phospholipase C-dependent hydrolysis of phosphatidylinositol 4,5-bisphosphate underlies agmatine-induced suppression of N-type Ca 2+ channel in rat celiac ganglion neurons. Biochem Biophys Res Commun 2017; 484:342-347. [PMID: 28131838 DOI: 10.1016/j.bbrc.2017.01.120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 01/23/2017] [Indexed: 12/27/2022]
Abstract
Agmatine suppresses peripheral sympathetic tone by modulating Cav2.2 channels in peripheral sympathetic neurons. However, the detailed cellular signaling mechanism underlying the agmatine-induced Cav2.2 inhibition remains unclear. Therefore, in the present study, we investigated the electrophysiological mechanism for the agmatine-induced inhibition of Cav2.2 current (ICav2.2) in rat celiac ganglion (CG) neurons. Consistent with previous reports, agmatine inhibited ICav2.2 in a VI manner. The agmatine-induced inhibition of the ICav2.2 current was also almost completely hindered by the blockade of the imidazoline I2 receptor (IR2), and an IR2 agonist mimicked the inhibitory effect of agmatine on ICav2.2, implying involvement of IR2. The agmatine-induced ICav2.2 inhibition was significantly hampered by the blockade of G protein or phospholipase C (PLC), but not by the pretreatment with pertussis toxin. In addition, diC8-phosphatidylinositol 4,5-bisphosphate (PIP2) dialysis nearly completely hampered agmatine-induced inhibition, which became irreversible when PIP2 resynthesis was blocked. These results suggest that in rat peripheral sympathetic neurons, agmatine-induced IR2 activation suppresses Cav2.2 channel voltage-independently, and that the PLC-dependent PIP2 hydrolysis is responsible for the agmatine-induced suppression of the Cav2.2 channel.
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Affiliation(s)
- Young-Hwan Kim
- Department of Physiology, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Ji-Hyun Jeong
- Department of Physiology, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Duck-Sun Ahn
- Department of Physiology, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Seungsoo Chung
- Department of Physiology, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
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8
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Keller B, García-Sevilla JA. Inhibitory effects of imidazoline receptor ligands on basal and kainic acid-induced neurotoxic signalling in mice. J Psychopharmacol 2016; 30:875-86. [PMID: 27302941 DOI: 10.1177/0269881116652579] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This in vivo study assessed the potential of the imidazoline receptor (IR) ligands moxonidine (selective I1-IR), BU224 (selective I2-IR) and LSL61122 (mixed I1/I2-IR) to dampen excitotoxic signalling induced by kainic acid (KA; 45 mg/kg) in the mouse brain (hippocampus and cerebral cortex). KA triggered a strong behavioural syndrome (seizures; maximal at 60-90 minutes) and sustained stimulation (at 72 hours with otherwise normal mouse behaviour) of pro-apoptotic c-Jun-N-terminal kinases (JNK) and calpain with increased cleavage of p35 into neurotoxic p25 (cyclin-dependent kinase 5 [Cdk5] activators) in mouse hippocampus. Pretreatment (five days) with LSL61122 (10 mg/kg), but not moxonidine (1 mg/kg) or BU224 (20 mg/kg), attenuated the KA-induced behavioural syndrome, and all three IR ligands inhibited JNK and calpain activation, as well as p35/p25 cleavage after KA in the hippocampus (effects also observed after acute IR drug treatments). Efaroxan (I1-IR, 10 mg/kg) and idazoxan (I2-IR, 10 mg/kg), postulated IR antagonists, did not antagonise the effects of moxonidine and LSL61122 on KA targets (these IR ligands showed agonistic properties inhibiting pro-apoptotic JNK). Brain subcellular preparations revealed reduced synaptosomal postsynaptic density-95 protein contents (a mediator of JNK activation) and indicated increased p35/Cdk5 complexes (with pro-survival functions) after treatment with moxonidine, BU224 and LSL61122. These results showed that I1- and I2-IR ligands (moxonidine and BU224), and especially the mixed I1/I2-IR ligand LSL61122, are partly neuroprotective against KA-induced excitotoxic signalling. These findings suggest a therapeutic potential of IR drugs in disorders associated with glutamate-mediated neurodegeneration.
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Affiliation(s)
- Benjamin Keller
- Laboratory of Neuropharmacology, IUNICS-IdISPa, University of the Balearic Islands (UIB), Palma de Mallorca, Spain Redes Temáticas de Investigación Cooperativa en Salud-Red de Trastornos Adictivos (RETICS-RTA), ISCIII, Madrid, Spain
| | - Jesús A García-Sevilla
- Laboratory of Neuropharmacology, IUNICS-IdISPa, University of the Balearic Islands (UIB), Palma de Mallorca, Spain Redes Temáticas de Investigación Cooperativa en Salud-Red de Trastornos Adictivos (RETICS-RTA), ISCIII, Madrid, Spain
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9
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Kim YH, Jeong JH, Ahn DS, Chung S. Agmatine suppresses peripheral sympathetic tone by inhibiting N-type Ca(2+) channel activity via imidazoline I2 receptor activation. Biochem Biophys Res Commun 2016; 477:406-12. [PMID: 27320860 DOI: 10.1016/j.bbrc.2016.06.086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 06/16/2016] [Indexed: 11/20/2022]
Abstract
Agmatine, a putative endogenous ligand of imidazoline receptors, suppresses cardiovascular function by inhibiting peripheral sympathetic tone. However, the molecular identity of imidazoline receptor subtypes and its cellular mechanism underlying the agmatine-induced sympathetic suppression remains unknown. Meanwhile, N-type Ca(2+) channels are important for the regulation of NA release in the peripheral sympathetic nervous system. Therefore, it is possible that agmatine suppresses NA release in peripheral sympathetic nerve terminals by inhibiting Ca(2+) influx through N-type Ca(2+) channels. We tested this hypothesis by investigating agmatine effect on electrical field stimulation (EFS)-evoked contraction and NA release in endothelium-denuded rat superior mesenteric arterial strips. We also investigated the effect of agmatine on the N-type Ca(2+) current in superior cervical ganglion (SCG) neurons in rats. Our study demonstrates that agmatine suppresses peripheral sympathetic outflow via the imidazoline I2 receptor in rat mesenteric arteries. In addition, the agmatine-induced suppression of peripheral vascular sympathetic tone is mediated by modulating voltage-dependent N-type Ca(2+) channels in sympathetic nerve terminals. These results suggest a potential cellular mechanism for the agmatine-induced suppression of peripheral sympathetic tone. Furthermore, they provide basic and theoretical information regarding the development of new agents to treat hypertension.
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Affiliation(s)
- Young-Hwan Kim
- Department of Physiology, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Ji-Hyun Jeong
- Department of Physiology, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Duck-Sun Ahn
- Department of Physiology, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Seungsoo Chung
- Department of Physiology, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
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Kim YH, Ahn DS, Kim MO, Joeng JH, Chung S. Protease-activated receptor 2 activation inhibits N-type Ca2+ currents in rat peripheral sympathetic neurons. Mol Cells 2014; 37:804-11. [PMID: 25410909 PMCID: PMC4255100 DOI: 10.14348/molcells.2014.0167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/02/2014] [Accepted: 09/17/2014] [Indexed: 11/27/2022] Open
Abstract
The protease-activated receptor (PAR)-2 is highly expressed in endothelial cells and vascular smooth muscle cells. It plays a crucial role in regulating blood pressure via the modulation of peripheral vascular tone. Although several mechanisms have been suggested to explain PAR-2-induced hypotension, the precise mechanism remains to be elucidated. To investigate this possibility, we investigated the effects of PAR-2 activation on N-type Ca(2+) currents (I(Ca-N)) in isolated neurons of the celiac ganglion (CG), which is involved in the sympathetic regulation of mesenteric artery vascular tone. PAR-2 agonists irreversibly diminished voltage-gated Ca(2+) currents (I(Ca)), measured using the patch-clamp method, in rat CG neurons, whereas thrombin had little effect on I(Ca). This PAR-2-induced inhibition was almost completely prevented by ω-CgTx, a potent N-type Ca(2+) channel blocker, suggesting the involvement of N-type Ca(2+) channels in PAR-2-induced inhibition. In addition, PAR-2 agonists inhibited I(Ca-N) in a voltage-independent manner in rat CG neurons. Moreover, PAR-2 agonists reduced action potential (AP) firing frequency as measured using the current-clamp method in rat CG neurons. This inhibition of AP firing induced by PAR-2 agonists was almost completely prevented by ω-CgTx, indicating that PAR-2 activation may regulate the membrane excitability of peripheral sympathetic neurons through modulation of N-type Ca(2+) channels. In conclusion, the present findings demonstrate that the activation of PAR-2 suppresses peripheral sympathetic outflow by modulating N-type Ca(2+) channel activity, which appears to be involved in PAR-2-induced hypotension, in peripheral sympathetic nerve terminals.
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Affiliation(s)
- Young-Hwan Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul 120-752,
Korea
| | - Duck-Sun Ahn
- Department of Physiology, Yonsei University College of Medicine, Seoul 120-752,
Korea
| | | | - Ji-Hyun Joeng
- Department of Physiology, Yonsei University College of Medicine, Seoul 120-752,
Korea
| | - Seungsoo Chung
- Department of Physiology, Yonsei University College of Medicine, Seoul 120-752,
Korea
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11
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Deconstructing the neural and ionic involvement of seizure-like events in the striatal network. Neurobiol Dis 2013; 52:128-36. [DOI: 10.1016/j.nbd.2012.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 11/28/2012] [Indexed: 02/07/2023] Open
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12
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Kim YH, Nam TS, Ahn DS, Chung S. Modulation of N-type Ca2+ currents by moxonidine via imidazoline I1 receptor activation in rat superior cervical ganglion neurons. Biochem Biophys Res Commun 2011; 409:645-50. [DOI: 10.1016/j.bbrc.2011.05.058] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 05/10/2011] [Indexed: 11/17/2022]
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13
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Dexmedetomidine and clonidine inhibit the function of Na(v)1.7 independent of α(2)-adrenoceptor in adrenal chromaffin cells. J Anesth 2011; 25:549-57. [PMID: 21607767 DOI: 10.1007/s00540-011-1168-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 04/28/2011] [Indexed: 12/19/2022]
Abstract
PURPOSE Besides being administered systemically for sedation and analgesia, α(2)-agonists such as dexmedetomidine and clonidine have been administered with intrathecal, epidural, or perineural injections, leading to an antinociceptive effect at the spinal cord or peripheral nerve level. However, the mechanism for this remains unclear. In the present study, we examined whether dexmedetomidine and clonidine could inhibit the function of tetrodotoxin-sensitive Na(+) channels, which play important roles in the generation of pain. METHODS Cultured bovine adrenal chromaffin cells expressing the tetrodotoxin-sensitive Na(v)1.7 Na(+) channel isoform were incubated in KRP buffer containing 2 μCi (22)NaCl for 5 min without or with dexmedetomidine or clonidine in the absence or presence of veratridine, α-scorpion venom, β-scorpion venom, Ptychodiscus brevis toxin-3 or ouabain. Cells were then washed and counted radioactively. RESULTS Dexmedetomidine and clonidine reduced veratridine-induced (22)Na(+) influx via Na(v)1.7 in a concentration-dependent manner (EC(50) = 50 μM and 530 μM), even in the presence of ouabain, an inhibitor of Na(+), K(+)-ATPase. Dexmedetomidine and clonidine shifted the concentration-response curve of veratridine for (22)Na(+) influx downward without altering the EC(50) of veratridine. Atipamezole and yohimbine, α(2)-antagonists, did not prevent the inhibition of veratridine-induced (22)Na(+) influx by dexmedetomidine. Dexmedetomidine and clonidine combined with lidocaine induced more inhibition of veratridine-induced (22)Na(+) influx than each drug did individually. Atipamezole and yohimbine did not prevent the lidocaine-enhancing effect of dexmedetomidine and clonidine. CONCLUSION Dexmedetomidine and clonidine inhibit the function of Na(v)1.7 independent of α(2)-adrenoceptor. These results may lead to a deeper understanding of the peripheral antinociceptive effects of α (2)-agonists.
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