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The opposite effect of convulsant drugs on neuronal and endothelial nitric oxide synthase - A possible explanation for the dual proconvulsive/anticonvulsive action of nitric oxide. ACTA PHARMACEUTICA (ZAGREB, CROATIA) 2023; 73:59-74. [PMID: 36692466 DOI: 10.2478/acph-2023-0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/21/2022] [Indexed: 01/25/2023]
Abstract
Nitric oxide (NO) participates in processes such as endothelium-dependent vasodilation and neurotransmission/neuromodulation. The role of NO in epilepsy is controversial, attributing it to anticonvulsant but also proconvulsant properties. Clarification of this dual effect of NO might lead to the development of new antiepileptic drugs. Previous results in our laboratory indicated that this contradictory role of NO in seizures could depend on the nitric oxide synthase (NOS) isoform involved, which could play opposite roles in epileptogenesis, one of them being proconvulsant but the other anticonvulsant. The effect of convulsant drugs on neuronal NO (nNO) and endothelial NO (eNO) levels was investigated. Considering the distribution of neuronal and endothelial NOS in neurons and astrocytes, resp., primary cultures of neurons and astrocytes were used as a study model. The effects of convulsant drugs pentylenetetrazole, thiosemicarbazide, 4-aminopyridine and bicuculline on NO levels were studied, using a spectrophotometric method. Their effects on NO levels in neurons and astrocytes depend on the concentration and time of treatment. These convulsant drugs caused an increase in nNO, but a decrease in eNO was proportional to the duration of treatment in both cases. Apparently, nNO possesses convulsant properties mediated by its effect on the glutamatergic and GABAergic systems, probably through GABAA receptors. Anticonvulsant properties of eNO may be the consequence of its effect on endothelial vasodilation and its capability to induce angiogenesis. Described effects last as seizures do. Considering the limitations of these kinds of studies and the unexplored influence of inducible NO, further investigations are required.
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Sokolov RA, Jappy D, Podgorny OV, Mukhina IV. Nitric Oxide Synthase Blockade Impairs Spontaneous Calcium Activity in Mouse Primary Hippocampal Culture Cells. Int J Mol Sci 2023; 24:ijms24032608. [PMID: 36768926 PMCID: PMC9917029 DOI: 10.3390/ijms24032608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/31/2023] Open
Abstract
Oscillation of intracellular calcium concentration is a stable phenomenon that affects cellular function throughout the lifetime of both electrically excitable and non-excitable cells. Nitric oxide, a gaseous secondary messenger and the product of nitric oxide synthase (NOS), affects intracellular calcium dynamics. Using mouse hippocampal primary cultures, we recorded the effect of NOS blockade on neuronal spontaneous calcium activity. There was a correlation between the amplitude of spontaneous calcium events and the number of action potentials (APs) (Spearman R = 0.94). There was a linear rise of DAF-FM fluorescent emission showing an increase in NO concentration with time in neurons (11.9 ± 1.0%). There is correlation between the integral of the signal from DAF-FM and the integral of the spontaneous calcium event signal from Oregon Green 488 (Spearman R = 0.58). Blockade of NOS affected the parameters of the spontaneous calcium events studied (amplitude, frequency, integral, rise slope and decay slope). NOS blockade by Nw-Nitro-L-arginine suppressed the amplitude and frequency of spontaneous calcium events. The NOS blocker 3-Bromo-7-Nitroindazole reduced the frequency but not the amplitude of spontaneous calcium activity. Blockade of the well-known regulator of NOS, calcineurin with cyclosporine A reduced the integral of calcium activity in neurons. The differences and similarities in the effects on the parameters of spontaneous calcium effects caused by different blockades of NO production help to improve understanding of how NO synthesis affects calcium dynamics in neurons.
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Affiliation(s)
- Rostislav A. Sokolov
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 603022 Nizhny Novgorod, Russia
- Institute of Translational Medicine, Pirogov Russian National Research Medical University, 117513 Moscow, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia
- Correspondence:
| | - David Jappy
- Institute of Fundamental Neurology, Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, 117997 Moscow, Russia
| | - Oleg V. Podgorny
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia
- Institute of Fundamental Neurology, Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, 117997 Moscow, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117513 Moscow, Russia
| | - Irina V. Mukhina
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 603022 Nizhny Novgorod, Russia
- Central Research Laboratory, Privolzhsky Research Medical University, 603005 Nizhny Novgorod, Russia
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Fernandez‐Perez EJ, Muñoz B, Bascuñan DA, Peters C, Riffo‐Lepe NO, Espinoza MP, Morgan PJ, Filippi C, Bourboulou R, Sengupta U, Kayed R, Epsztein J, Aguayo LG. Synaptic dysregulation and hyperexcitability induced by intracellular amyloid beta oligomers. Aging Cell 2021; 20:e13455. [PMID: 34409748 PMCID: PMC8441418 DOI: 10.1111/acel.13455] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/21/2021] [Accepted: 08/05/2021] [Indexed: 12/19/2022] Open
Abstract
Intracellular amyloid beta oligomer (iAβo) accumulation and neuronal hyperexcitability are two crucial events at early stages of Alzheimer's disease (AD). However, to date, no mechanism linking iAβo with an increase in neuronal excitability has been reported. Here, the effects of human AD brain-derived (h-iAβo) and synthetic (iAβo) peptides on synaptic currents and action potential firing were investigated in hippocampal neurons. Starting from 500 pM, iAβo rapidly increased the frequency of synaptic currents and higher concentrations potentiated the AMPA receptor-mediated current. Both effects were PKC-dependent. Parallel recordings of synaptic currents and nitric oxide (NO)-associated fluorescence showed that the increased frequency, related to pre-synaptic release, was dependent on a NO-mediated retrograde signaling. Moreover, increased synchronization in NO production was also observed in neurons neighboring those dialyzed with iAβo, indicating that iAβo can increase network excitability at a distance. Current-clamp recordings suggested that iAβo increased neuronal excitability via AMPA-driven synaptic activity without altering membrane intrinsic properties. These results strongly indicate that iAβo causes functional spreading of hyperexcitability through a synaptic-driven mechanism and offers an important neuropathological significance to intracellular species in the initial stages of AD, which include brain hyperexcitability and seizures.
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Affiliation(s)
| | - Braulio Muñoz
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Denisse A. Bascuñan
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Christian Peters
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Nicolas O. Riffo‐Lepe
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Maria P. Espinoza
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Peter J. Morgan
- Institute of Neurobiology of the Mediterranean Sea (INMED)Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille UniversitéMarseilleFrance
| | - Caroline Filippi
- Institute of Neurobiology of the Mediterranean Sea (INMED)Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille UniversitéMarseilleFrance
| | - Romain Bourboulou
- Institute of Neurobiology of the Mediterranean Sea (INMED)Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille UniversitéMarseilleFrance
| | - Urmi Sengupta
- Mitchell Center for Neurodegenerative DiseasesUniversity of Texas Medical BranchGalvestonTexasUSA
- Department of Neurology, Neuroscience and Cell BiologyUniversity of Texas Medical BranchGalvestonTexasUSA
| | - Rakez Kayed
- Mitchell Center for Neurodegenerative DiseasesUniversity of Texas Medical BranchGalvestonTexasUSA
- Department of Neurology, Neuroscience and Cell BiologyUniversity of Texas Medical BranchGalvestonTexasUSA
| | - Jérôme Epsztein
- Institute of Neurobiology of the Mediterranean Sea (INMED)Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille UniversitéMarseilleFrance
| | - Luis G. Aguayo
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
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Bratek E, Ziembowicz A, Salinska E. N-Acetylaspartylglutamate (NAAG) Pretreatment Reduces Hypoxic-Ischemic Brain Damage and Oxidative Stress in Neonatal Rats. Antioxidants (Basel) 2020; 9:antiox9090877. [PMID: 32957477 PMCID: PMC7555246 DOI: 10.3390/antiox9090877] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/08/2020] [Accepted: 09/14/2020] [Indexed: 12/15/2022] Open
Abstract
N-acetylaspartylglutamate (NAAG), the most abundant peptide transmitter in the mammalian nervous system, activates mGluR3 at presynaptic sites, inhibiting the release of glutamate, and acts on mGluR3 on astrocytes, stimulating the release of neuroprotective growth factors (TGF-β). NAAG can also affect N-methyl-d-aspartate (NMDA) receptors in both synaptic and extrasynaptic regions. NAAG reduces neurodegeneration in a neonatal rat model of hypoxia-ischemia (HI), although the exact mechanism is not fully recognized. In the present study, the effect of NAAG application 24 or 1 h before experimental birth asphyxia on oxidative stress markers and the potential mechanisms of neuroprotection on 7-day old rats was investigated. The intraperitoneal application of NAAG at either time point before HI significantly reduced the weight deficit of the ischemic brain hemisphere, radical oxygen species (ROS) content and activity of antioxidant enzymes, and increased the concentration of reduced glutathione (GSH). No additional increase in the TGF-β concentration was observed after NAAG application. The fast metabolism of NAAG and the decrease in TGF-β concentration that resulted from NAAG pretreatment, performed up to 24 h before HI, excluded the involvement mGluR3 in neuroprotection. The observed effect may be explained by the activation of NMDA receptors induced by NAAG pretreatment 24 h before HI. Inhibition of the NAAG effect by memantine supports this conclusion. NAAG preconditioning 1 h before HI results in a mixture of mGluR3 and NMDA receptor activation. Preconditioning with NAAG induces the antioxidative defense system triggered by mild excitotoxicity in neurons. Moreover, this response to NAAG pretreatment is consistent with the commonly accepted mechanism of preconditioning. However, this theory requires further investigation.
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Singh P, Walia V. Anxiolytic like effect of L-Carnitine in mice: Evidences for the involvement of NO-sGC-cGMP signaling pathway. Behav Brain Res 2020; 391:112689. [PMID: 32417275 DOI: 10.1016/j.bbr.2020.112689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/26/2020] [Accepted: 05/02/2020] [Indexed: 12/20/2022]
Abstract
L-Carnitine (LC) is an endogenous compound synthesized from the essential amino acids lysine and methionine. LC act as an antioxidant and modulates the levels of neurochemicals such as glutamate, GABA, NO etc. implicated in the regulation of anxiety and related behavior. However its exact role in the anxiety is not known. The present study was designed to investigate the anxiolytic like effect of LC in mice. LC (2.5, 5.0 and 10 mg/kg, i.p.) was administered to the mice and the anxiety related behavior was determined using light and dark box (LDB) and elevated plus maze (EPM) tests. The whole brain nitrite level was also determined. The results obtained demonstrated that LC (10 mg/kg, i.p.) exerted anxiolytic like effect in mice, accompanied by the reduction of whole brain nitrite level significantly as compared to control. Further, the influence of NO and GABA modulators pretreatments on the effect of subtherapeutic dose of LC was also determined. The results obtained demonstrated that NO donor/cGMP modulator counteracted while NO inhibitor potentiated the effect confers by the subtherapeutic dose of LC mice. Pretreatment of diazepam (1 mg/kg, i.p.) further potentiated the effect of subtherapeutic dose of LC (5 mg/kg, i.p.) in EPM and LDB tests and further reduced the brain nitrite level significantly as compared to LC (5 mg/kg, i.p.) alone treatment. Thus, LC exerted anxiolytic like effect in mice and NO-sGC-cGMP signaling pathway influences the anxiolytic like effect of LC in mice.
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Affiliation(s)
- Poonam Singh
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, 124001, Haryana, India.
| | - Vaibhav Walia
- Faculty of Pharmacy, DIT University, Dehradun, India.
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Walia V, Garg C, Garg M. Amantadine exerts anxiolytic like effect in mice: Evidences for the involvement of nitrergic and GABAergic signaling pathways. Behav Brain Res 2019; 380:112432. [PMID: 31838141 DOI: 10.1016/j.bbr.2019.112432] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 12/08/2019] [Accepted: 12/11/2019] [Indexed: 01/08/2023]
Abstract
Amantadine is a glutamatergic antagonist that works by inhibiting the NMDA receptor. Besides the inhibition of NMDA receptors amantadine also stabilizes the glutamatergic system and protects the neurons against the NMDA toxicity. Amantadine treatment also reduces the production of NO and metabolism of GABA. Therefore amantadine modulates glutamate, GABA and NO which are known to be implicated in the pathogenesis of anxiety and related behavior. The present study was designed to investigate the anxiolytic like effect of amantadine in mice. Nitrergic and GABAergic signaling influence in the anxiolytic like effect of amantadine was also studied. Amantadine (25, 50 and 75 mg/kg, i.p.) was administered and the anxiety related behavior was determined using light and dark box (LDB) and elevated plus maze (EPM) methods. Further, the effect of various treatments on the whole brain glutamate, nitrite and GABA levels were also determined. The results obtained demonstrated that the amantadine (50 mg/kg, i.p.) exerted anxiolytic like effect in mice and reduced the levels of glutamate, nitrite and GABA in the brain of mice as compared to control. Further, the influence of NO and GABA in the anxiolytic like effect of the amantadine was also determined. The results obtained demonstrated that NO donor counteracted while NO inhibitor potentiated the anxiolytic like effect of amantadine in mice. Also the combined treatment of amantadine (25 mg/kg, i.p.) and diazepam (1 mg/kg, i.p.) did not affect the anxiety related behavior, brain GABA and nitrite level of mice but reduced the levels the brain glutamate levels significantly as compared to amantadine (25 mg/kg, i.p.) and diazepam (1 mg/kg, i.p.) treated mice. Thus, amantadine exerted anxiolytic like effect in mice and the anxiolytic like effect of amantadine was modulated by nitrergic and GABAergic signaling pathway.
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Affiliation(s)
- Vaibhav Walia
- Faculty of Pharmacy, DIT University, Dehradun, India.
| | - Chanchal Garg
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak 124001, Haryana, India.
| | - Munish Garg
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak 124001, Haryana, India.
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Wang C, Wang X, Xu L, Cheng Y. Neuroprotective Activity of Icariin Against Hypoxic-ischemic Brain Injury in Neonatal Rats. INT J PHARMACOL 2019. [DOI: 10.3923/ijp.2019.829.836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Walia V, Garg C, Garg M. Nitrergic signaling modulation by ascorbic acid treatment is responsible for anxiolysis in mouse model of anxiety. Behav Brain Res 2019; 364:85-98. [PMID: 30738102 DOI: 10.1016/j.bbr.2019.02.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/16/2019] [Accepted: 02/04/2019] [Indexed: 10/27/2022]
Abstract
The present study was designed to investigate the effect of ascorbic acid (AA) treatment on the anxiety related behavioral and neurochemical alterations. AA (50, 100 and 200 mg/kg, i.p.) was administered to the mice and anxiety related behavior and levels of glutamate and nitrite in the brain of mice were determined. The results obtained revealed that the administration of AA (100 mg/kg, i.p.) significantly reduced the anxiety related behavior and the levels of nitrite in the brain of mice. Nitrergic interactions were further determined by the pretreatment of mice with nitric oxide (NO) modulator and AA treatment followed by behavioral and neurochemical measurements. The results obtained suggested that NO inhibition potentiated the anxiolytic like activity of AA in mice. It was also observed that the glutamate and nitrite level in the brain of mice were significantly reduced by the NO inhibitor pretreatment. Thus, the present study demonstrated the possible nitrergic pathways modulation in the anxiolytic like activity of AA in mice.
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Affiliation(s)
- Vaibhav Walia
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak-124001, Haryana, India.
| | - Chanchal Garg
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak-124001, Haryana, India.
| | - Munish Garg
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak-124001, Haryana, India.
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Gao Y, Fu R, Wang J, Yang X, Wen L, Feng J. Resveratrol mitigates the oxidative stress mediated by hypoxic-ischemic brain injury in neonatal rats via Nrf2/HO-1 pathway. PHARMACEUTICAL BIOLOGY 2018; 56:440-449. [PMID: 30460866 PMCID: PMC6249550 DOI: 10.1080/13880209.2018.1502326] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/11/2018] [Accepted: 07/15/2018] [Indexed: 06/01/2023]
Abstract
CONTEXT Hypoxic-ischemic encephalopathy (HIE) has a high morbidity and mortality rate. Resveratrol possesses numerous biological properties including antioxidant, anti-inflammatory and neuroprotective activities. OBJECTIVE The current experiment investigates the neuroprotective efficacy of resveratrol (RESV) against HIE by modulating Nrf2/HO-1 pathway in neonatal rats. MATERIALS AND METHODS Seven-day-old pups (n = 48) were divided into four groups. Group-I rats receiving 2% DMSO saline (sham), group-II rats underwent unilateral carotid artery ligation and hypoxia (92% N2 and 8% O2) for 2.5 h (hypoxia-ischemia; HI), group-III and IV rats received 20 (RESV 20 + HI) or 40 mg/kg (RESV 40 + HI; group-IV) of RESV via intraperitoneal injection (ip), respectively, for 7 days prior to HI induction. RESULTS Pre-treatment with RESV (20 or 40) markedly reduced (p < 0.01) the cerebral oedema (86.23-71.26 or 65.24%), infarct area (33.85-19.81 or 14.30%), lipid peroxidation products, inflammatory markers [IL-1β 186-110 or 82; IL-6 255-146 or 103; TNF-α 310-204 or 137; NF-κB 205-115 or 91) p65 subunit] and significantly restored (p < 0.01) the antioxidative status by enhancing the activities of glutathione peroxidase (GPx) 5.22-6.49 or 7.78; catalase (CAT) 51-55 or 59, superoxide dismutase (SOD) 2.5-3.05 or 3.25; through marked upregulation (p < 0.01) of heme oxygenase 1 (HO-1) 0.65-0.69 or 0.73; and nuclear factor erythroid 2 related factor 2 (Nrf2) 0.73-0.86 or 0.91. DISCUSSION AND CONCLUSIONS RESV displays its neurotherapeutic potential via upregulating the protein expression of Nrf2 and HO-1 signalling pathway and thereby attenuates oxidative stress and inflammatory response in HI-induced neonatal rats.
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Affiliation(s)
- Yan Gao
- Department of Neurology, Shengjing Hospital Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Rongrong Fu
- Department of Neurology, Shengjing Hospital Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Jue Wang
- Department of Neurology, Shengjing Hospital Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Xue Yang
- Department of Neurology, Shengjing Hospital Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Lulu Wen
- Department of Neurology, Shengjing Hospital Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Juan Feng
- Department of Neurology, Shengjing Hospital Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
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Islas-Espinoza AM, Campos-Rodriguez C, San Juan ER. Thalidomide protects against acute pentylenetetrazol and pilocarpine-induced seizures in mice. J Toxicol Sci 2018; 43:671-684. [PMID: 30405000 DOI: 10.2131/jts.43.671] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Thalidomide was originally developed to treat primary neurological and psychiatric diseases. There are reports of anticonvulsant effects of thalidomide in rats and antiepileptic effects in patients. Hence, thalidomide (100, 200 and 400 mg/kg) was herein administered to mice to evaluate possible protection against seizures induced by the systemic administration of neurotoxins: 10 mg/kg of 4-aminopyridine (4-AP), 90 mg/kg of pentylenetetrazol (PTZ), or 380 mg/kg of pilocarpine. The effect of an NO and COX inhibitor (7-NI and ibuprofen, respectively) was also examined. The results show that thalidomide (1) induces the typical sedative effects, (2) has no anticonvulsant effect in mice treated with 4-AP, and (3) has anticonvulsant effect (400 mg/kg) in mice treated with PTZ and pilocarpine. It was found that 7-NI has an anticonvulsant effect in the pilocarpine model and that thalidomide's effect is not enhanced by its presence. However, thalidomide (200 mg/kg) plus 7-NI or ibuprofen tend to have a toxic effect in PTZ model. On the other hand, the combination of thalidomide and 7-NI or ibuprofen protects against pilocarpine-induced seizures. In conclusion, thalidomide did not exert an anticonvulsant effect for clonic-tonic type convulsions (4-AP), but it did so for seizures induced by PTZ and pilocarpine (representing absence seizures and status epilepticus, respectively). NO and prostaglandins were involved in the convulsive process elicited by pilocarpine.
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Affiliation(s)
- Ana Mara Islas-Espinoza
- Physiology Department, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Unidad Profesional Adolfo López Mateos, Mexico
| | - Carolina Campos-Rodriguez
- Physiology Department, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Unidad Profesional Adolfo López Mateos, Mexico
| | - Eduardo Ramírez San Juan
- Physiology Department, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Unidad Profesional Adolfo López Mateos, Mexico
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NO-sGC-cGMP signaling influence the anxiolytic like effect of lithium in mice in light and dark box and elevated plus maze. Brain Res 2018; 1704:114-126. [PMID: 30292770 DOI: 10.1016/j.brainres.2018.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 09/17/2018] [Accepted: 10/02/2018] [Indexed: 11/23/2022]
Abstract
Glutamate is an excitatory neurotransmitter implicated in the pathogenesis of psychiatric disorders. Glutamate results in the activation of an enzyme called glycogen synthase kinase-3 (GSK-3) acting through N-methyl-d-aspartate (NMDA) receptors. Impaired expression of GSK-3 affects behavior and neurochemicals level in the brain responsible for the pathogenesis of mood disorders. It has been reported that lithium acts as an inhibitor of GSK-3 and inhibit the enzyme GSK-3 in an uncompetitive manner. In the present study, anxiolytic like effect of lithium in mice is investigated through light and dark box (LDB) and elevated plus maze (EPM). Lithium (50, 100 and 200 mg/kg, i.p.) was administered to the mice to determine the anxiety related behavior. Results obtained suggests that the administration of lithium (100 mg/kg, i.p.) reversed the anxiety related behavior of mice and decreased the levels of glutamate and nitrite as compared to control. Glutamate acting through the NMDA receptor has been found to regulate the expression of enzyme neuronal nitric oxide synthase (nNOS), which is responsible for the release of nitric oxide (NO), suggesting a possible link between NO and GSK-3 also. Therefore, to determine the possible interaction with NO, sub-effective dose of lithium was administered in combination with NO donor i.e. l-Arginine (50 mg/kg, i.p.), NOS and soluble guanylate cyclase (sGC) inhibitor i.e. methylene blue (1 mg/kg, i.p.) and phosphodiesterase inhibitor i.e. sildenafil (1 mg/kg, i.p.). The results obtained demonstrated that the anxiolytic like effect of lithium was abolished by the pretreatment with NO donor and potentiated by the pretreatment with NOS inhibitor. Therefore, it is suggested that NO signaling pathway influence the anxiolytic like activity of lithium in mice, further suggesting the link between the GSK-3 and NO signaling in the regulation of anxiety related behavior.
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Walia V, Garg C, Garg M. Anxiolytic-like effect of pyridoxine in mice by elevated plus maze and light and dark box: Evidence for the involvement of GABAergic and NO-sGC-cGMP pathway. Pharmacol Biochem Behav 2018; 173:96-106. [PMID: 30040985 DOI: 10.1016/j.pbb.2018.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/21/2018] [Accepted: 06/11/2018] [Indexed: 10/28/2022]
Abstract
Present study was carried out to investigate the 'anxiolytic-like' effect of pyridoxine in mice. Pyridoxine (90, 180 and 360 mg/kg) was administered by intraperitoneal (i.p.) route to the experimental mice and anxiety-related behavior was evaluated by light and dark box (LDB) and elevated plus maze (EPM) models. Glutamate, GABA and nitrite levels were also determined in the isolated whole brain of mice. It was observed that pyridoxine (180 mg/kg, i.p.) exerted 'anxiolytic-like' effect in mice in EPM and LDB models. Also, there was a significant increase in the levels of GABA whereas; the levels of glutamate and nitrite were decreased as compared to the control group. Administration of pentamethylene tetrazole (PTZ; 20 mg/kg, i.p.) exerted anxiogenic effects in mice, but the combination of PTZ and pyridoxine (180 mg/kg, i.p.) abolished the 'anxiolytic-like' effect of pyridoxine, thereby, suggesting the possible role of GABA in the 'anxiolytic-like' effect of pyridoxine in mice. Further, the influence of NO-sGC-cGMP pathway was investigated by administering the sub-effective dose of pyridoxine in combination with sub-threshold doses of NO modulators i.e. l‑arginine (50 mg/kg, i.p.; NO donor); methylene blue (1 mg/kg, i.p.; NO and soluble guanylate cyclase inhibitor) and sildenafil (1 mg/kg, i.p.; phosphodiesterase inhibitor and cGMP modulator). It was observed that the 'anxiolytic-like' effect of pyridoxine in mice was counteracted by the NO donor and potentiated by the NO inhibitors. Thus, the present study confirmed the involvement of GABAergic and NO-sGC-cGMP pathway in the 'anxiolytic-like' effect of pyridoxine in mice.
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Affiliation(s)
- Vaibhav Walia
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak 124001, Haryana, India
| | - Chanchal Garg
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak 124001, Haryana, India
| | - Munish Garg
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak 124001, Haryana, India.
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Su CK, Chen YY, Ho CM. Nitric Oxide Orchestrates a Power-Law Modulation of Sympathetic Firing Behaviors in Neonatal Rat Spinal Cords. Front Physiol 2018; 9:163. [PMID: 29559921 PMCID: PMC5845561 DOI: 10.3389/fphys.2018.00163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 02/19/2018] [Indexed: 11/13/2022] Open
Abstract
Nitric oxide (NO) is a diffusible gas and has multifarious effects on both pre- and postsynaptic events. As a consequence of complex excitatory and inhibitory integrations, NO effects on neuronal activities are heterogeneous. Using in vitro preparations of neonatal rats that retain the splanchnic sympathetic nerves and the thoracic spinal cord as an experimental model, we report here that either enhancement or attenuation of NO production in the neonatal rat spinal cords could increase, decrease, or not change the spontaneous firing behaviors recorded from splanchnic sympathetic single fibers. To elucidate the mathematical features of NO-mediated heterogeneous responses, the ratios of changes in firing were plotted against their original firing rates. In log-log plots, a linear data distribution demonstrated that NO-mediated heterogeneity in sympathetic firing responses was well described by a power function. Selective antagonists were applied to test if glycinergic, GABAergic, glutamatergic, and cholinergic neurotransmission in the spinal cord are involved in NO-mediated power-law firing modulations (plFM). NO-mediated plFM diminished in the presence of mecamylamine (an open-channel blocker of nicotinic cholinergic receptors), indicating that endogenous nicotinic receptor activities were essential for plFM. Applications of strychnine (a glycine receptor blocker), gabazine (a GABAA receptor blocker), or kynurenate (a broad-spectrum ionotropic glutamate receptor blocker) also caused plFM. However, strychnine- or kynurenate-induced plFM was diminished by L-NAME (an NO synthase inhibitor) pretreatments, indicating that the involvements of glycine or ionotropic glutamate receptor activities in plFM were secondary to NO signaling. To recapitulate the arithmetic natures of the plFM, the plFM were simulated by firing changes in two components: a step increment and a fractional reduction of their basal firing activities. Ionotropic glutamate receptor activities were found to participate in plFM by both components. In contrast, GABAA receptor activities are involved in the component of fractional reduction only. These findings suggest that NO orchestrates a repertoire of excitatory and inhibitory neurotransmissions, incurs a shunting effect on postsynaptic membrane properties, and thus, alters sympathetic firing in a manner of plFM. We propose that the plFM mediated by NO forms a basic scheme of differential controls for heterogeneous sympathetic regulation of visceral functions.
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Affiliation(s)
- Chun-Kuei Su
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yi-Yin Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chiu-Ming Ho
- Department of Anesthesiology, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
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14
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Marks WD, Paris JJ, Schier CJ, Denton MD, Fitting S, McQuiston AR, Knapp PE, Hauser KF. HIV-1 Tat causes cognitive deficits and selective loss of parvalbumin, somatostatin, and neuronal nitric oxide synthase expressing hippocampal CA1 interneuron subpopulations. J Neurovirol 2016; 22:747-762. [PMID: 27178324 PMCID: PMC5107352 DOI: 10.1007/s13365-016-0447-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 04/02/2016] [Accepted: 04/10/2016] [Indexed: 02/08/2023]
Abstract
Memory deficits are characteristic of HIV-associated neurocognitive disorders (HAND) and co-occur with hippocampal pathology. The HIV-1 transactivator of transcription (Tat), a regulatory protein, plays a significant role in these events, but the cellular mechanisms involved are poorly understood. Within the hippocampus, diverse populations of interneurons form complex networks; even subtle disruptions can drastically alter synaptic output, resulting in behavioral dysfunction. We hypothesized that HIV-1 Tat would impair cognitive behavior and injure specific hippocampal interneuron subtypes. Male transgenic mice that inducibly expressed HIV-1 Tat (or non-expressing controls) were assessed for cognitive behavior or had hippocampal CA1 subregions evaluated via interneuron subpopulation markers. Tat exposure decreased spatial memory in a Barnes maze and mnemonic performance in a novel object recognition test. Tat reduced the percentage of neurons expressing neuronal nitric oxide synthase (nNOS) without neuropeptide Y immunoreactivity in the stratum pyramidale and the stratum radiatum, parvalbumin in the stratum pyramidale, and somatostatin in the stratum oriens, which are consistent with reductions in interneuron-specific interneuron type 3 (IS3), bistratified, and oriens-lacunosum-moleculare interneurons, respectively. The findings reveal that an interconnected ensemble of CA1 nNOS-expressing interneurons, the IS3 cells, as well as subpopulations of parvalbumin- and somatostatin-expressing interneurons are preferentially vulnerable to HIV-1 Tat. Importantly, the susceptible interneurons form a microcircuit thought to be involved in feedback inhibition of CA1 pyramidal cells and gating of CA1 pyramidal cell inputs. The identification of vulnerable CA1 hippocampal interneurons may provide novel insight into the basic mechanisms underlying key functional and neurobehavioral deficits associated with HAND.
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Affiliation(s)
- William D Marks
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298-0613, USA
| | - Jason J Paris
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298-0613, USA
| | - Christina J Schier
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298-0613, USA
| | - Melissa D Denton
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298-0613, USA
| | - Sylvia Fitting
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3270, USA
| | - A Rory McQuiston
- Department of Anatomy & Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0709, USA
| | - Pamela E Knapp
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298-0613, USA
- Department of Anatomy & Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0709, USA
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, 23298-0059, USA
| | - Kurt F Hauser
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298-0613, USA.
- Department of Anatomy & Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0709, USA.
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, 23298-0059, USA.
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15
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Urrutia M, Fernández S, González M, Vilches R, Rojas P, Vásquez M, Kurte M, Vega-Letter AM, Carrión F, Figueroa F, Rojas P, Irarrázabal C, Fuentealba RA. Overexpression of Glutamate Decarboxylase in Mesenchymal Stem Cells Enhances Their Immunosuppressive Properties and Increases GABA and Nitric Oxide Levels. PLoS One 2016; 11:e0163735. [PMID: 27662193 PMCID: PMC5035029 DOI: 10.1371/journal.pone.0163735] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 09/13/2016] [Indexed: 12/12/2022] Open
Abstract
The neurotransmitter GABA has been recently identified as a potent immunosuppressive agent that targets both innate and adaptive immune systems and prevents disease progression of several autoimmunity models. Mesenchymal stem cells (MSCs) are self-renewing progenitor cells that differentiate into various cell types under specific conditions, including neurons. In addition, MSC possess strong immunosuppressive capabilities. Upon cytokine priming, undifferentiated MSC suppress T-cell proliferation via cell-to-cell contact mechanisms and the secretion of soluble factors like nitric oxide, prostaglandin E2 and IDO. Although MSC and MSC-derived neuron-like cells express some GABAergic markers in vitro, the role for GABAergic signaling in MSC-mediated immunosuppression remains completely unexplored. Here, we demonstrate that pro-inflammatory cytokines selectively regulate GAD-67 expression in murine bone marrow-MSC. However, expression of GAD-65 is required for maximal GABA release by MSC. Gain of function experiments using GAD-67 and GAD-65 co-expression demonstrates that GAD increases immunosuppressive function in the absence of pro-inflammatory licensing. Moreover, GAD expression in MSC evokes an increase in both GABA and NO levels in the supernatants of co-cultured MSC with activated splenocytes. Notably, the increase in NO levels by GAD expression was not observed in cultures of isolated MSC expressing GAD, suggesting crosstalk between these two pathways in the setting of immunosuppression. These results indicate that GAD expression increases MSC-mediated immunosuppression via secretion of immunosuppressive agents. Our findings may help reconsider GABAergic activation in MSC for immunological disorders.
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Affiliation(s)
- Mariana Urrutia
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Sebastián Fernández
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Marisol González
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Rodrigo Vilches
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Pablo Rojas
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Manuel Vásquez
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Mónica Kurte
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Ana María Vega-Letter
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Flavio Carrión
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Fernando Figueroa
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Patricio Rojas
- Departamento de Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Carlos Irarrázabal
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
| | - Rodrigo A. Fuentealba
- Centro de Investigación Biomédica, Facultad de Medicina, Universidad de Los Andes, Santiago, Chile
- * E-mail:
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Changes in Brain Swelling and Infarction Volume over Four Days After Hypoxia Ischemia in Neonatal Rats. ACTA NEUROCHIRURGICA. SUPPLEMENT 2016; 121:111-4. [PMID: 26463932 DOI: 10.1007/978-3-319-18497-5_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The leading cause of morbidity and mortality in infants is hypoxia-ischemia (HI). The current therapies for HI have limited success, in part due to a lack of understanding of HI pathophysiology and underlying mechanisms. Herein, a neonatal rat model of HI was used to examine the changes in brain swelling and infarct volume over 4 days after HI. Forty-four P10 rat pups were sacrificed at 2, 3, or 4 days post-HI. After sacrifice, the brains were removed, sliced, and stained with TTC (2,3,5-triphenyl-2H-tetrazolium chloride). Images of TTC-stained brains were used for measurement of the ipsilateral hemisphere brain volumes and infarct volumes, calculated using standard equations. The hemispheric brain volumes of HI animals in all groups was lower than that of sham animals and decreased as the post-HI sacrifice time increased. The infarct volume of HI animals was larger than that of sham animals. Infarct volumes tended to decrease over the days post-HI. The change in infarct volume is likely the result of a combination of brain growth and repair mechanisms. However, changes in the hemispheric brain volume may include tissue growth and repair mechanism, so also may be a limitation of the current algorithm used for calculating ipsilateral hemisphere brain volume.
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Li L, McBride DW, Doycheva D, Dixon BJ, Krafft PR, Zhang JH, Tang J. G-CSF attenuates neuroinflammation and stabilizes the blood-brain barrier via the PI3K/Akt/GSK-3β signaling pathway following neonatal hypoxia-ischemia in rats. Exp Neurol 2015; 272:135-44. [PMID: 25585014 PMCID: PMC4499024 DOI: 10.1016/j.expneurol.2014.12.020] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 12/22/2014] [Accepted: 12/25/2014] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Neonatal hypoxia occurs in approximately 60% of premature births and is associated with a multitude of neurological disorders. While various treatments have been developed, translating them from bench to bedside has been limited. We previously showed G-CSF administration was neuroprotective in a neonatal hypoxia-ischemia rat pup model, leading us to hypothesize that G-CSF inactivation of GSK-3β via the PI3K/Akt pathway may attenuate neuroinflammation and stabilize the blood-brain barrier (BBB). METHODS P10 Sprague-Dawley rat pups were subjected to unilateral carotid artery ligation followed by hypoxia for 2.5h. We assessed inflammation by measuring expression levels of IKKβ, NF-κB, TNF-α, IL-1β, IL-10, and IL-12 as well as neutrophil infiltration. BBB stabilization was evaluated by measuring Evans blue extravasation, and Western blot analysis of Claudin-3, Claudin-5, ICAM-1, and VCAM-1. MEASUREMENTS AND MAIN RESULTS First, the time course study showed that p-β-catenin/β-catenin, IKKβ, and NF-κB expression levels peaked at 48h post-HI. The knockdown of GSK-3β with siRNA prevented the HI-induced increase of p-β-catenin/β-catenin, IKKβ, and NF-κB expression levels 48h after HI. G-CSF treatment reduced brain water content and neuroinflammation by downregulating IKKβ, NF-κB, TNF-α, IL-1β, and IL-12 and upregulating IL-10, thereby reducing neutrophil infiltration. Additionally, G-CSF stabilizes the BBB by downregulating VCAM-1 and ICAM-1, as well as upregulating Claudins 3 and 5 in endothelial cells. G-CSFR knockdown by siRNA and Akt inhibition by Wortmannin reversed G-CSF's neuroprotective effects. CONCLUSIONS We demonstrate G-CSF plays a pivotal role in attenuating neuroinflammation and BBB disruption following HI by inactivating GSK-3β through the PI3K/Akt pathway.
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Affiliation(s)
- Li Li
- Departments of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Devin W McBride
- Departments of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Desislava Doycheva
- Departments of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Brandon J Dixon
- Departments of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Paul R Krafft
- Departments of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - John H Zhang
- Departments of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, CA, USA; Department of Anesthesiology, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Jiping Tang
- Departments of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, CA, USA.
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18
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Parlog A, Schlüter D, Dunay IR. Toxoplasma gondii-induced neuronal alterations. Parasite Immunol 2015; 37:159-70. [PMID: 25376390 DOI: 10.1111/pim.12157] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 10/31/2014] [Indexed: 12/13/2022]
Abstract
The zoonotic pathogen Toxoplasma gondii infects over 30% of the human population. The intracellular parasite can persist lifelong in the CNS within neurons modifying their function and structure, thus leading to specific behavioural changes of the host. In recent years, several in vitro studies and murine models have focused on the elucidation of these modifications. Furthermore, investigations of the human population have correlated Toxoplasma seropositivity with changes in neurological functions; however, the complex underlying mechanisms of the subtle behavioural alteration are still not fully understood. The parasites are able to induce direct modifications in the infected cells, for example by altering dopamine metabolism, by functionally silencing neurons as well as by hindering apoptosis. Moreover, indirect effects of the peripheral immune system and alterations of the immune status of the CNS, observed during chronic infection, might also contribute to changes in neuronal connectivity and synaptic plasticity. In this review, we will provide an overview and highlight recent advances, which describe changes in the neuronal function and morphology upon T. gondii infection.
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Affiliation(s)
- A Parlog
- Institute of Medical Microbiology and Hospital Hygiene, Otto-von-Guericke University, Magdeburg, Germany
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19
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Gasulla J, Calvo DJ. Enhancement of tonic and phasic GABAergic currents following nitric oxide synthase inhibition in hippocampal CA1 pyramidal neurons. Neurosci Lett 2015; 590:29-34. [PMID: 25636692 DOI: 10.1016/j.neulet.2015.01.058] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/21/2015] [Accepted: 01/22/2015] [Indexed: 01/23/2023]
Abstract
Nitric oxide (NO) is involved in synaptic plasticity in the hippocampus through different presynaptic and postsynaptic mechanisms that include the modulation of the GABAergic neurotransmission. Inhibitory synapses on hippocampal pyramidal neurons are known to possess the molecular machinery for retrograde NO-signaling, but the modulation of GABAARs function by NO in these neurons and the mechanisms of action involved have not been fully characterized. Here we show that suppression of the endogenous NO generation by the nitric oxide synthase (NOS) inhibitor L-NAME produces significant and reversible increases in the magnitude of both tonic and phasic GABAergic currents in CA1 hippocampal pyramidal neurons. GABA-evoked chloride currents were measured in the presence or absence of L-NAME using whole-cell patch-clamp recordings in acute hippocampal slices from young adult mice. Enhancement of the tonic GABA responses induced by L-NAME was insensitive to TTX and decreased by co-incubation with the NO donor DEA/NO. Applications of DEA/NO alone did not produce significant effects on tonic GABA responses. L-NAME treatment also increased the amplitude of phasic GABAergic currents evoked by GABA-puffs. Our results indicate that the extent of tonic and phasic inhibition mediated by GABAA receptors in CA1 hippocampal pyramidal neurons is affected by endogenous NO production.
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Affiliation(s)
- Javier Gasulla
- Laboratorio de Neurobiología Celular y Molecular Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) "Dr. Héctor N. Torres", Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Vuelta de Obligado 2490, Ciudad Autónoma de Buenos Aires (CP 1428), Argentina
| | - Daniel J Calvo
- Laboratorio de Neurobiología Celular y Molecular Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) "Dr. Héctor N. Torres", Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Vuelta de Obligado 2490, Ciudad Autónoma de Buenos Aires (CP 1428), Argentina.
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20
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Li L, Klebe D, Doycheva D, McBride DW, Krafft PR, Flores J, Zhou C, Zhang JH, Tang J. G-CSF ameliorates neuronal apoptosis through GSK-3β inhibition in neonatal hypoxia-ischemia in rats. Exp Neurol 2014; 263:141-9. [PMID: 25448005 DOI: 10.1016/j.expneurol.2014.10.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 09/26/2014] [Accepted: 10/10/2014] [Indexed: 12/25/2022]
Abstract
Granulocyte-colony stimulating factor (G-CSF), a growth factor, has known neuroprotective effects in a variety of experimental brain injury models. Herein we show that G-CSF administration attenuates neuronal apoptosis after neonatal hypoxia-ischemia (HI) via glycogen synthase kinase-3β (GSK-3β) inhibition. Ten day old Sprague-Dawley rat pups (n=157) were subjected to unilateral carotid artery ligation followed by 2.5h of hypoxia or sham surgery. HI animals received control siRNA, GSK-3β siRNA (4 μL/pup), G-CSF (50 μg/kg), G-CSF combined with 0.1 or 0.4 nM G-CSF receptor (G-CSFR) siRNA, phosphatidylinositol 3-kinase (PI3K) inhibitor Wortmannin (86 ng/pup), or DMSO (vehicle for Wortmannin). Pups were euthanized 48 h post-HI to quantify brain infarct volume. G-CSFR, activated Akt (p-Akt), activated GSK-3β (p-GSK-3β), Cleaved Caspase-3 (CC3), Bcl-2, and Bax were quantified using Western blot analysis and the localizations of each was visualized via immunofluorescence staining. Neuronal cell death was determined using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). Our results showed p-GSK-3β increased after HI until its peak at 48 h post-ictus, and both GSK-3β siRNA and G-CSF administration reduced p-GSK-3β expression, as well as infarct volume. p-GSK-3β and CC3 were generally co-localized in neurons. Furthermore, G-CSF increased p-Akt expression and the Bcl-2/Bax ratio and also decreased p-GSK-3β and CC3 expression levels in the ipsilateral hemisphere, which were all reversed by G-CSFR siRNA, Wortmannin, and GSK-3β siRNA. In conclusion, G-CSF attenuated caspase activation and reduced brain injury by inhibiting GSK-3β activity after experimental HI in rat pups. This neuroprotective effect was abolished by both G-CSFR siRNA and Wortmannin.
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Affiliation(s)
- Li Li
- Department of Anatomy & Histology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China; Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Damon Klebe
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Desislava Doycheva
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Devin W McBride
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Paul R Krafft
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Jerry Flores
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Changman Zhou
- Department of Anatomy & Histology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - John H Zhang
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA; Departments of Anesthesiology and Neurosurgery, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Jiping Tang
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA.
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Neuronal nitric oxide synthase-dependent S-nitrosylation of gephyrin regulates gephyrin clustering at GABAergic synapses. J Neurosci 2014; 34:7763-8. [PMID: 24899700 DOI: 10.1523/jneurosci.0531-14.2014] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Gephyrin, the principal scaffolding protein at inhibitory synapses, is essential for postsynaptic clustering of glycine and GABA type A receptors (GABA(A)Rs). Gephyrin cluster formation, which determines the strength of GABAergic transmission, is modulated by interaction with signaling proteins and post-translational modifications. Here, we show that gephyrin was found to be associated with neuronal nitric oxide synthase (nNOS), the major source of the ubiquitous and important signaling molecule NO in brain. Furthermore, we identified that gephyrin is S-nitrosylated in vivo. Overexpression of nNOS decreased the size of postsynaptic gephyrin clusters in primary hippocampal neurons. Conversely, inhibition of nNOS resulted in a loss of S-nitrosylation of gephyrin and the formation of larger gephyrin clusters at synaptic sites, ultimately increasing the number of cell surface expressed synaptic GABA(A)Rs. In conclusion, S-nitrosylation of gephyrin is important for homeostatic assembly and plasticity of GABAergic synapses.
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Doycheva DM, Hadley T, Li L, Applegate RL, Zhang JH, Tang J. Anti-neutrophil antibody enhances the neuroprotective effects of G-CSF by decreasing number of neutrophils in hypoxic ischemic neonatal rat model. Neurobiol Dis 2014; 69:192-9. [PMID: 24874543 DOI: 10.1016/j.nbd.2014.05.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 04/09/2014] [Accepted: 05/17/2014] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES Neonatal hypoxia ischemia (HI) is an injury that can lead to neurological impairments such as behavioral and learning disabilities. Granulocyte-colony stimulating factor (G-CSF) has been demonstrated to be neuroprotective in ischemic stroke however it has also been shown to induce neutrophilia, ultimately exacerbating neuronal injury. Our hypothesis is that coadministration of anti-neutrophil antibody (Ab) with G-CSF will decrease blood neutrophil counts thereby reducing infarct volume and improving neurological function post HI brain injury. METHODS Rat pups were subjected to unilateral carotid artery ligation followed by 2.5h of hypoxia. Animals were randomly assigned to five groups: Sham (n=15), vehicle (HI, n=15), HI with G-CSF treatment (n=15), HI with G-CSF+Ab treatment (n=15), and HI with Ab treatment (n=15). Ab (325μg/kg) was administered intraperitoneally while G-CSF (50μg/kg) was administered subcutaneously 1h post HI followed by daily injections for 3 consecutive days. Animals were euthanized at 96h post HI for blood neutrophil counts and brain infarct volume measurements as well as at 5weeks for neurological function testing and brain weight measurements. Lung and spleen weights at both time points were further analyzed. RESULTS The G-CSF treatment group showed tendencies to reduce infarct volume and improve neurological function while significantly increasing neutrophil counts. On the other hand, the G-CSF+Ab group significantly reduced infarct volume, improved neurological function and decreased neutrophil counts. The Ab alone group showed reversal of the neuroprotective effects of the G-CSF+Ab group. No significant differences were found in peripheral organ weights between groups. CONCLUSION Our data suggest that coadministration of G-CSF with Ab not only prevented brain atrophy but also significantly improved neurological function by decreasing blood neutrophil counts. Hence the neuroprotective effects of G-CSF may be further enhanced if neutrophilia is avoided.
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Affiliation(s)
- Desislava M Doycheva
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Tiffany Hadley
- Department of Anaesthesiology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Li Li
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Richard L Applegate
- Department of Anaesthesiology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - John H Zhang
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA; Department of Neurosurgery, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Jiping Tang
- Department of Physiology & Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA, USA.
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Jafari-Sabet M, Khodadadnejad MA, Ghoraba S, Ataee R. Nitric oxide in the dorsal hippocampal area is involved on muscimol state-dependent memory in the step-down passive avoidance test. Pharmacol Biochem Behav 2014; 117:137-43. [DOI: 10.1016/j.pbb.2013.12.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 09/06/2013] [Accepted: 12/06/2013] [Indexed: 10/25/2022]
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Gasulla J, Beltrán González AN, Calvo DJ. Nitric oxide potentiation of the homomeric ρ1 GABA(C) receptor function. Br J Pharmacol 2013; 167:1369-77. [PMID: 22747884 DOI: 10.1111/j.1476-5381.2012.02087.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND AND PURPOSE NO is a highly diffusible and reactive gas produced in the nervous system, which acts as a neuronal signal mediating physiological or pathological mechanisms. NO can modulate the activity of neurotransmitter receptors and ion channels, including NMDA and GABA(A) receptors. In the present work, we examined whether GABA(C) receptor function can also be regulated by NO. EXPERIMENTAL APPROACH Homomeric ρ1 GABA(C) receptors were expressed in oocytes and GABA-evoked responses electrophysiologically recorded in the presence or absence of the NO donor DEA. Chemical protection of cysteines by selective sulfhydryl reagents and site-directed mutagenesis were used to determine the protein residues involved in the actions of NO. KEY RESULTS GABAρ1 receptor responses were significantly enhanced in a dose-dependent, fast and reversible manner by DEA and the specific NO scavenger CPTIO prevented these potentiating effects. The ρ1 subunits contain only three cysteine residues, two extracellular at the Cys-loop (C177 and C191) and one intracellular (C364). Mutations of C177 and C191 render the ρ1 GABA receptors non-functional, but C364 can be safely exchanged by alanine (C364A). NEM, N-ethyl maleimide and (2-aminoethyl) methanethiosulfonate prevented the effects of DEA on GABAρ1 receptors. Meanwhile, the potentiating effects of DEA on mutant GABAρ1(C364A) receptors were similar to those observed on wild-type receptors. CONCLUSIONS AND IMPLICATIONS Our results suggest that the function of GABA(C) receptors can be enhanced by NO acting at the extracellular Cys-loop.
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Affiliation(s)
- J Gasulla
- Laboratorio de Neurobiología Celular y Molecular, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
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Liang Z, Zhang L, Wang X, Gao F, Wang X, Zhou S, Yu S, Zhan RZ. Distribution and neurochemical features of neuronal nitric oxide synthase-expressing interneurons in the rat dentate gyrus. Brain Res 2013; 1505:11-21. [PMID: 23419891 DOI: 10.1016/j.brainres.2013.02.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 02/09/2013] [Accepted: 02/09/2013] [Indexed: 12/13/2022]
Abstract
Neuronal nitric oxide synthase (nNOS)-expressing interneurons are abundant in the dentate gyrus (DG) of rodents. In the present study, we immunohistochemically analyzed nNOS-positive cells in the rat DG by focusing on their GABAergicity, laminar distribution, and co-localization with calcium-binding proteins and neuropeptides. Experiments were conducted in adult male Sprague Dawley rats. Within the DG, nNOS-positive cells were found to reside in all three layers of DG; percentages of distribution in the molecular layer, granule cell layer and the hilus are 25.4%, 9.4% and 65.2%, respectively. Almost every nNOS-positive cell expressed glutamic acid decarboxylase 67 (GAD67) or glutamic acid decarboxylase 65 (GAD65). In the molecular layer, nearly two-thirds of GAD67-positive cells expressed nNOS. Percentages of nNOS-positive interneurons that expressed cholecystokinin, vasoactive intestinal polypeptide, parvalbumin, somatostatin, neuropeptide Y, and calretinin were approximately 0.8%, 1.8%, 9.2%, 10.3%, 13.8%, and 24.4%, respectively. In the molecular layer, the number of nNOS-positive cells far exceeded the sum total of cells positive for both nNOS and any of the above mentioned calcium-binding proteins or neuropeptides, indicating that a large proportion of nNOS-positive interneurons seldom express calcium-binding proteins or neuropeptides in this area. We conclude that nNOS expressing cells are an important neurochemically defined type of GABAergic interneuron in the rat DG showing a specific laminar-dependent distribution and expressing calcium-binding proteins and neuropeptides at different frequencies. In the molecular layer, most nNOS-positive interneurons do not express calcium-binding proteins or neuropeptides; they could be the missing pieces in the GABAergic interneuron jigsaw puzzle of this DG layer.
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Affiliation(s)
- Zhaoliang Liang
- Institute of Physiology, Shandong University School of Medicine, 44 Wenhua Xi Road, Jinan, China
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Yang J, Liu Z, Xie Y, Yang Z, Zhang T. Peroxynitrite alters GABAergic synaptic transmission in immature rat hippocampal slices. Neurosci Res 2013; 75:210-7. [PMID: 23357207 DOI: 10.1016/j.neures.2013.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Revised: 01/04/2013] [Accepted: 01/07/2013] [Indexed: 02/01/2023]
Abstract
Increasing of peroxynitrite (ONOO(-)) production during ischemia in the immature brain was considered to be associated with impaired cognitive function. GABAergic synapses played an important role in memory formation including the induction of long-term potentiation (LTP) and long-term depression (LTD) in hippocampus. In the present study, we examined the effects of acute exposure of the ONOO(-) donor, SIN-1 on GABAergic synaptic transmission in immature rat hippocampal slices with whole-cell patch-clamp recordings. The results showed that SIN-1 increased the peak amplitude of evoked inhibitory postsynaptic currents (eIPSCs) and decreased paired pulse ratio via the formation of ONOO(-). In addition, it also increased the frequency of spontaneous (but not miniature) IPSCs in a dose-dependent manner without altering amplitudes or rise and decay times of both (sIPSCs and mIPSCs). It further demonstrated that the presynaptic action of SIN-1 was external calcium dependent and was not related to the changes of interneuron excitability. This study provides electrophysiological evidences from developing hippocampal slices to support that SIN-1 enhances action potential-dependent GABA release. It suggests that the potentiation effect of ONOO(-) may contribute to hyperexcitability and seizures and may underlie one of the mechanisms by which ischemia increases seizure susceptibility in the immature brain.
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Affiliation(s)
- Jiajia Yang
- College of Life Sciences, Nankai University, Tianjin 300071, PR China
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Armstrong C, Krook-Magnuson E, Soltesz I. Neurogliaform and Ivy Cells: A Major Family of nNOS Expressing GABAergic Neurons. Front Neural Circuits 2012; 6:23. [PMID: 22623913 PMCID: PMC3353154 DOI: 10.3389/fncir.2012.00023] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 04/13/2012] [Indexed: 12/05/2022] Open
Abstract
Neurogliaform and Ivy cells are members of an abundant family of neuronal nitric oxide synthase (nNOS) expressing GABAergic interneurons found in diverse brain regions. These cells have a defining dense local axonal plexus, and display unique synaptic properties including a biphasic postsynaptic response with both a slow GABA(A) component and a GABA(B) component following even a single action potential. The type of transmission displayed by these cells has been termed "volume transmission," distinct from both tonic and classical synaptic transmission. Electrical connections are also notable in that, unlike other GABAergic cell types, neurogliaform family cells will form gap junctions not only with other neurogliaform cells, but also with non-neurogliaform family GABAergic cells. In this review, we focus on neurogliaform and Ivy cells throughout the hippocampal formation, where recent studies highlight their role in feedforward inhibition, uncover their ability to display a phenomenon called persistent firing, and reveal their modulation by opioids. The unique properties of this family of cells, their abundance, rich connectivity, and modulation by clinically relevant drugs make them an attractive target for future studies in vivo during different behavioral and pharmacological conditions.
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Affiliation(s)
- Caren Armstrong
- Department of Anatomy and Neurobiology, University of California IrvineIrvine, CA, USA
| | - Esther Krook-Magnuson
- Department of Anatomy and Neurobiology, University of California IrvineIrvine, CA, USA
| | - Ivan Soltesz
- Department of Anatomy and Neurobiology, University of California IrvineIrvine, CA, USA
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Prieto-Martín AI, Llorens S, Pardal-Fernández JM, Muñoz LJ, López DE, Escribano J, Nava E, de Cabo C. Opposite caudal versus rostral brain nitric oxide synthase response to generalized seizures in a novel rodent model of reflex epilepsy. Life Sci 2012; 90:531-7. [DOI: 10.1016/j.lfs.2012.01.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 01/09/2012] [Accepted: 01/19/2012] [Indexed: 01/09/2023]
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Zhao YD, Cheng SY, Ou S, Chen PH, Ruan HZ. Functional response of hippocampal CA1 pyramidal cells to neonatal hypoxic-ischemic brain damage. Neurosci Lett 2012; 516:5-8. [PMID: 22402191 DOI: 10.1016/j.neulet.2012.02.067] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 01/11/2012] [Accepted: 02/21/2012] [Indexed: 11/24/2022]
Abstract
Perinatal hypoxic-ischemic (H-I) is a major cause of brain injury in the newborn. The hippocampus is more sensitive to H-I injury than the other brain regions. It is believed that H-I brain damage causes a loss of neurons in the central nervous system. The patterns of neuronal death include apoptosis and necrosis. With regard to the responses of neurons, the neural functional changes should be earlier than the morphologic changes. The aim of the present study is to evaluate the electrophysiological characteristics and the synaptic transmission functions. Seven-day-old Sprague-Dawley rat pups were randomly divided into sham operation and H-I groups. The patch clamp, immunohistochemistry and Western blotting techniques were used to achieve this objective. The results of the study showed a decrease in neuronal excitability and a significant increase in the frequency of spontaneous excitatory postsynaptic currents and the duration of EPSCs in the CA1 pyramidal cells of H-I brain damage rats. The glutamate transporter subtype 1 (GLT-1) expression level of the hippocampal CA1 area in the H-I group was decreased compared with the control. There was no difference in the amplitude of excitatory postsynaptic currents and should be no difference in the expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR), N-methyl-D-aspartate receptor (NMDAR) and synaptophysin between the control and H-I brain injury group. These results revealed that changes of electrophysiological characteristics and synaptic functions occur instantly after H-I brain damage in the hippocampal pyramidal cells of neonatal rats. The failure to eliminate glutamate should be one of the important factors of excitotoxicity injury on hippocampal CA1 pyramidal cells, while neuronal excitation was not increased in the H-I brain injury model.
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Affiliation(s)
- Yan-Dong Zhao
- Department of Neurobiology, College of Basic Medical Sciences, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
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Modulation of in vivo GABA-evoked responses by nitric oxide-active compounds in the globus pallidus of rat. J Neural Transm (Vienna) 2012; 119:911-21. [DOI: 10.1007/s00702-011-0760-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 12/25/2011] [Indexed: 10/14/2022]
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Peng JF, Wu ZT, Wang YK, Yuan WJ, Sun T, Ni X, Su DF, Wang W, Xu MJ, Wang WZ. GABAergic mechanism in the rostral ventrolateral medulla contributes to the hypotension of moxonidine. Cardiovasc Res 2010; 89:473-81. [PMID: 20829217 DOI: 10.1093/cvr/cvq289] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS The depressor action of the centrally antihypertensive drug moxonidine has been attributed to activation of I(1)-imidazoline receptor in the rostral ventrolateral medulla (RVLM). The objective of this study was to determine the role of the γ-aminobutyric acid (GABA) mechanisms in the RVLM in mediating the effect of moxonidine in anaesthetized normotensive rats. METHODS AND RESULTS The relationship between the effects of microinjection or picoinjection of moxonidine and the functional state of GABA receptors at the level of the RVLM or pre-sympathetic neuron was determined. Microdialysis was performed to detect the effect of moxonidine on the release of GABA in the RVLM. Western blot analysis was carried out to test the effect of chronic intracerebroventricular injection of moxonidine on the protein expression of GABA receptors in the RVLM. Pre-treatment with the GABA(A) or GABA(B) receptor antagonist bicuculline (5 pmol) or CGP35348 (200 pmol), respectively, microinjected into the RVLM significantly attenuated the decrease in blood pressure and renal sympathetic nerve activity induced by moxonidine. In 22 moxonidine-sensitive pre-sympathetic neurons in the RVLM, picoinjection of bicuculline (100 fmol/5 nL) significantly attenuated the neuronal inhibition evoked by moxonidine (100 pmol/5 nL). The release of GABA in the RVLM was increased after intravenous moxonidine (50 μg/kg). Central infusion of moxonidine upregulated the protein expression of both GABA(A) and GABA(B) receptors in the RVLM. CONCLUSION The current data demonstrate that GABAergic mechanisms in the RVLM are responsible for the hypotension and sympathoinhibition of moxonidine.
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Affiliation(s)
- Jun-Feng Peng
- Department of Physiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China
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