1
|
Liu J, Lin D, Yau A, Cottrell JE, Kass IS. Early-life propofol exposure does not affect later-life GABAergic inhibition, seizure induction, or social behavior. IBRO Neurosci Rep 2023; 14:483-493. [PMID: 37252630 PMCID: PMC10220478 DOI: 10.1016/j.ibneur.2023.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 05/13/2023] [Indexed: 05/31/2023] Open
Abstract
The early developing brain is especially vulnerable to anesthesia, which can result in long lasting functional changes. We examined the effects of early-life propofol on adult excitatory-inhibitory balance and behavior. Postnatal day 7 male mice were exposed to propofol (250 mg/kg i.p.) and anesthesia was maintained for 2 h; control mice were given the same volume of isotonic saline and treated identically. The behavior and electrophysiology experiments were conducted when the mice were adults. We found that a 2-h neonatal propofol exposure did not significantly reduce paired pulse inhibition, alter the effect of muscimol (3 µM) to inhibit field excitatory postsynaptic potentials or alter the effect of bicuculline (100 µM) to increase the population spike in the CA1 region of hippocampal slices from adult mice. Neonatal propofol did not alter the evoked seizure response to pentylenetetrazol in adult mice. Neonatal propofol did not affect anxiety, as measured in the open field apparatus, depression-like behavior, as measured by the forced swim test, or social interactions with novel mice, in either the three-chamber or reciprocal social tests. These results were different from those with neonatal sevoflurane which demonstrated reduced adult GABAergic inhibition, increased seizure susceptibility and reduced social interaction. Even though sevoflurane and propofol both prominently enhance GABA inhibition, they have unique properties that alter the long-term effects of early-life exposure. These results indicate that clinical studies grouping several general anesthetic agents in a single group should be interpreted with great caution when examining long-term effects.
Collapse
Affiliation(s)
- Jinyang Liu
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
| | - Daisy Lin
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
- Department of Physiology and Pharmacology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
| | - Alice Yau
- State University of New York Downstate Health Sciences University College of Medicine, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
| | - James E. Cottrell
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
| | - Ira S. Kass
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
- Department of Physiology and Pharmacology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
| |
Collapse
|
2
|
Lin D, Liu J, Florveus A, Ganesan V, Cottrell JE, Kass IS. Exposure to Sevoflurane, But Not Ketamine, During Early-life Brain Development has Long-Lasting Effects on GABA A Receptor Mediated Inhibitory Neurotransmission. Neuroscience 2021; 472:116-127. [PMID: 34384844 DOI: 10.1016/j.neuroscience.2021.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 11/19/2022]
Abstract
Understanding the different mechanisms associated with different anesthetic targeted receptors is critical towards identifying accurate long-term outcome measures as a result of early-life anesthetic exposure. We examined changes in GABAA receptor mediated neurotransmission by a predominately GABAA receptor targeted anesthetic, sevoflurane or a predominately NMDA receptor targeted anesthetic, ketamine. Postnatal day 7 male mice were exposed to sevoflurane or ketamine and examined as adults for changes in inhibitory neurotransmission and its associated change in induced seizure activity. Paired pulse stimulation experiment showed that early-life sevoflurane treated mice had significantly less hippocampal CA1 inhibition later in life. There was significantly increased CA1 excitatory output in the sevoflurane treated group compared to the no sevoflurane treated group after the GABA agonist muscimol. Similar to our previously established data for early-life sevoflurane, here we established early-life ketamine administration resulted in neurodevelopmental behavioral changes later in life. However, muscimol did not produce a significant difference on the excitatory CA1 output between early-life ketamine group and saline group. While sevoflurane treated mice showed significantly higher induced seizure intensities and shorter latency periods to reach seizure intensity stage 5 (Racine score) compared with no sevoflurane treated mice, this phenomenon was not observed in the ketamine vs. saline treated groups. Early-life sevoflurane, but not ketamine, exposure reduced GABAergic inhibition and enhanced seizure activity later in life. The results indicate that early-life exposure to different anesthetics lead to distinct long-term effects and their unique pathways require mechanistic studies to understand induced long-lasting changes in the brain.
Collapse
Affiliation(s)
- Daisy Lin
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA; Department of Physiology and Pharmacology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
| | - Jinyang Liu
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
| | - Alizna Florveus
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
| | - Vanathi Ganesan
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
| | - James E Cottrell
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
| | - Ira S Kass
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA; Department of Physiology and Pharmacology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA.
| |
Collapse
|
3
|
Berthoux C, Hamieh AM, Rogliardo A, Doucet EL, Coudert C, Ango F, Grychowska K, Chaumont‐Dubel S, Zajdel P, Maldonado R, Bockaert J, Marin P, Bécamel C. Early 5-HT 6 receptor blockade prevents symptom onset in a model of adolescent cannabis abuse. EMBO Mol Med 2020; 12:e10605. [PMID: 32329240 PMCID: PMC7207164 DOI: 10.15252/emmm.201910605] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 03/05/2020] [Accepted: 03/10/2020] [Indexed: 01/05/2023] Open
Abstract
Cannabis abuse during adolescence confers an increased risk for developing later in life cognitive deficits reminiscent of those observed in schizophrenia, suggesting common pathological mechanisms that remain poorly characterized. In line with previous findings that revealed a role of 5-HT6 receptor-operated mTOR activation in cognitive deficits of rodent developmental models of schizophrenia, we show that chronic administration of ∆9-tetrahydrocannabinol (THC) to mice during adolescence induces a long-lasting activation of mTOR in prefrontal cortex (PFC), alterations of excitatory/inhibitory balance, intrinsic properties of layer V pyramidal neurons, and long-term depression, as well as cognitive deficits in adulthood. All are prevented by administrating a 5-HT6 receptor antagonist or rapamycin, during adolescence. In contrast, they are still present 2 weeks after the same treatments delivered at the adult stage. Collectively, these findings suggest a role of 5-HT6 receptor-operated mTOR signaling in abnormalities of cortical network wiring elicited by THC at a critical period of PFC maturation and highlight the potential of 5-HT6 receptor antagonists as early therapy to prevent cognitive symptom onset in adolescent cannabis abusers.
Collapse
Affiliation(s)
| | | | | | | | - Camille Coudert
- IGF, University of MontpellierCNRS, INSERMMontpellierFrance
- Department of Adult PsychiatryMontpellier University HospitalMontpellierFrance
| | - Fabrice Ango
- IGF, University of MontpellierCNRS, INSERMMontpellierFrance
| | - Katarzyna Grychowska
- Department of Medicinal ChemistryJagiellonian University Medical CollegeKrakówPoland
| | | | - Pawel Zajdel
- Department of Medicinal ChemistryJagiellonian University Medical CollegeKrakówPoland
| | - Rafael Maldonado
- Neuropharmacology LaboratoryDepartment of Experimental and Health SciencesPompeu Fabra UniversityBarcelonaSpain
| | - Joël Bockaert
- IGF, University of MontpellierCNRS, INSERMMontpellierFrance
| | - Philippe Marin
- IGF, University of MontpellierCNRS, INSERMMontpellierFrance
| | - Carine Bécamel
- IGF, University of MontpellierCNRS, INSERMMontpellierFrance
| |
Collapse
|
4
|
Granule of BU-XIN RUAN-MAI Attenuates the Patients' Angina Pectoris of Coronary Heart Disease via Regulating miR-542-3p/GABARAP Signaling. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2019; 2019:1808419. [PMID: 31949464 PMCID: PMC6948311 DOI: 10.1155/2019/1808419] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 10/15/2019] [Accepted: 10/23/2019] [Indexed: 12/22/2022]
Abstract
Objective Coronary heart disease (CHD) has been regarded as a serious and common disease in the modern society. This study aims to investigate the effect of Granule of BU-XIN RUAN-MAI (BXRM) on angina pectoris of coronary heart disease and to explore the molecular mechanisms underlying Granule of BU-XIN RUAN-MAI-mediated protective activity against this disease. Methods The effects of Granule of BU-XIN RUAN-MAI on clinical symptoms of patients' angina were indicated by hemorheology indicators including high shear of blood viscosity, low shear of blood viscosity, plasma viscosity, erythrocyte rigidity index, D-D dimer, fibrinogen content, and lipid content. The effects of Granule of BU-XIN RUAN-MAI on isoprenaline-induced myocardial cell injury were determined by conducting H&E staining and by performing ELISA to examine the serum content of MDA, SOD, Na+/K+-ATPase, cAMP, and the content of inflammatory factors in isoprenaline-induced rats. Meanwhile, western blot and real time PCR were used to determine the expression of genes involved in oxidation and energy metabolism, and real time PCR was also used for determination of miR-542-3p expression. Luciferase reporter assay was conducted to test the binding sites of miR-542-3p on GABARAP 3'UTR. The chemical compositions of Granule of BU-XIN RUAN-MAI were determined by liquid LC-QTOF-MS. Results Granule of BU-XIN RUAN-MAI significantly attenuated the clinical symptoms of patients' angina by improving the patients' heart rate and by decreasing the level of hemorheology indicators and also by reducing the serum content of TC, TG, LDL, and elevated HDL content. H&E staining demonstrated that Granule of BU-XIN RUAN-MAI ameliorated the myocardial ischemia in a dose-dependent manner. Besides, Granule of BU-XIN RUAN-MAI downregulated serum MDA content and upregulated the content of SOD, Na+/K+-ATPase, and cAMP in isoprenaline-induced rats. Granule of BU-XIN RUAN-MAI significantly improved oxidation stress by increasing PPARα expression, and it inhibited inflammation by downregulating expression and contents of IL-6, IL-1β, and TNF-α. Then, Granule of BU-XIN RUAN-MAI-containing serum increased the SOD content, and reduced the MDA content in angiotensin II-stimulated HUVEC cells. The granule of BU-XIN RUAN-MAI-containing serum obviously downregulated protein expressions of P40phox, P47phox, and P67phox in plasma membrane, and it significantly increased protein levels of P40phox, P47phox, and P67phox in the cytoplasm of HUVEC cells. Furthermore, GABARAP was reduced in heart tissues of ISO-induced rats and in angiotensin II-stimulated cell lines, and GABARAP was required for the inhibitory activity of Granule of BU-XIN RUAN-MAI on oxidation and inflammation in vivo and in vivo. GABARAP could be upregulated by Granule of BU-XIN RUAN-MAI by inhibiting the expression of miR-542-3p, which may significantly enhance oxidation and inflammation by targeting GABARAP in cardiomyocytes. Moreover, the silencing of GABARAP could obviously reverse the granule of BU-XIN RUAN-MAI-mediated protective activity against coronary heart disease, and interfering GABARAP expression also could partly block the anti-miR-542-3p-controlled oxidation and inflammation in cardiomyocytes. Besides, salidroside, loganin, and polydatin were the main compounds of granules of BU-XIN RUAN-MAI. Conclusion Granule of BU-XIN RUAN-MAI is an excellent prescription for treatment of coronary heart disease by suppressing inflammation and NAPDH-mediated oxidative stress. The miR-542-3p/GABARAP axis is required for Granule of BU-XIN RUAN-MAI, exhibiting its protective activity against the pectoris of coronary heart disease.
Collapse
|
5
|
Chang Y, Hsieh HL, Huang SK, Wang SJ. Neurosteroid allopregnanolone inhibits glutamate release from rat cerebrocortical nerve terminals. Synapse 2018; 73:e22076. [PMID: 30362283 DOI: 10.1002/syn.22076] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 10/17/2018] [Accepted: 10/19/2018] [Indexed: 12/15/2022]
Abstract
Allopregnanolone, an active metabolite of progesterone, has been reported to exhibit neuroprotective activity in several preclinical models. Considering that the excitotoxicity caused by excessive glutamate is implicated in many brain disorders, the effect of allopregnanolone on glutamate release in rat cerebrocortical nerve terminals and possible underlying mechanism were investigated. We observed that allopregnanolone inhibited 4-aminopyridine (4-AP)-evoked glutamate release, and this inhibition was prevented by chelating the extracellular Ca2+ ions and the vesicular transporter inhibitor. Allopregnanolone reduced the elevation of 4-AP-evoked intrasynaptosomal Ca2+ levels, but did not affect the synaptosomal membrane potential. In the presence of N-, P/Q-, and R-type channel blockers, allopregnanolone-mediated inhibition of 4-AP-evoked glutamate release was markedly reduced; however, the intracellular Ca2+ -release inhibitors did not affect the allopregnanolone effect. Furthermore, allopregnanolone-mediated inhibition of 4-AP-evoked glutamate release was completely abolished in the synaptosomes pretreated with inhibitors of Ca2+ /calmodulin, adenylate cyclase, and protein kinase A (PKA), namely calmidazolium, MDL12330A, and H89, respectively. Additionally, the allopregnanolone effect on evoked glutamate release was antagonized by the GABAA receptor antagonist SR95531. Our data are the first to suggest that allopregnanolone reduce the Ca2+ influx through N-, P/Q-, and R-type Ca2+ channels, through the activation of GABAA receptors present on cerebrocortical nerve terminals, subsequently suppressing the Ca2+ -calmodulin/PKA cascade and decreasing 4-AP-evoked glutamate release.
Collapse
Affiliation(s)
- Yi Chang
- Department of Anesthesiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.,School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Hsi Lung Hsieh
- Department of Nursing, Division of Basic Medical Sciences, Research Center for Chinese Herbal Medicine, and Graduate Institute of Health Industry Technology, Chang Gung University of Science and Technology, Tao-Yuan, Taiwan
| | - Shu Kuei Huang
- Department of Anesthesiology, Far-Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Su Jane Wang
- School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan.,Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan
| |
Collapse
|
6
|
Subramanian S, Reichard RA, Stevenson HS, Schwartz ZM, Parsley KP, Zahm DS. Lateral preoptic and ventral pallidal roles in locomotion and other movements. Brain Struct Funct 2018; 223:2907-2924. [PMID: 29700637 PMCID: PMC5997555 DOI: 10.1007/s00429-018-1669-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 04/19/2018] [Indexed: 12/31/2022]
Abstract
The lateral preoptic area (LPO) and ventral pallidum (VP) are structurally and functionally distinct territories in the subcommissural basal forebrain. It was recently shown that unilateral infusion of the GABAA receptor antagonist, bicuculline, into the LPO strongly invigorates exploratory locomotion, whereas bicuculline infused unilaterally into the VP has a negligible locomotor effect, but when infused bilaterally, produces vigorous, abnormal pivoting and gnawing movements and compulsive ingestion. This study was done to further characterize these responses. We observed that bilateral LPO infusions of bicuculline activate exploratory locomotion only slightly more potently than unilateral infusions and that unilateral and bilateral LPO injections of the GABAA receptor agonist muscimol potently suppress basal locomotion, but only modestly inhibit locomotion invigorated by amphetamine. In contrast, unilateral infusions of muscimol into the VP affect basal and amphetamine-elicited locomotion negligibly, but bilateral VP muscimol infusions profoundly suppress both. Locomotor activation elicited from the LPO by bicuculline was inhibited modestly and profoundly by blockade of dopamine D2 and D1 receptors, respectively, but was not entirely abolished even under combined blockade of dopamine D1 and D2 receptors. That is, infusing the LPO with bic caused instances of near normal, even if sporadic, invigoration of locomotion in the presence of saturating dopamine receptor blockade, indicating that LPO can stimulate locomotion in the absence of dopamine signaling. Pivoting following bilateral VP bicuculline infusions was unaffected by dopamine D2 receptor blockade, but was completely suppressed by D1 receptor blockade. The present results are discussed in a context of neuroanatomical and functional organization underlying exploratory locomotion and adaptive movements.
Collapse
Affiliation(s)
- Suriya Subramanian
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Saint Louis, MO, 63104, USA
| | - Rhett A Reichard
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Saint Louis, MO, 63104, USA
| | - Hunter S Stevenson
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Saint Louis, MO, 63104, USA
| | - Zachary M Schwartz
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Saint Louis, MO, 63104, USA
| | - Kenneth P Parsley
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Saint Louis, MO, 63104, USA
| | - Daniel S Zahm
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Saint Louis, MO, 63104, USA.
| |
Collapse
|
7
|
Wakita M, Shoudai K, Oyama Y, Akaike N. 4,5-Dichloro-2-octyl-4-isothiazolin-3-one (DCOIT) modifies synaptic transmission in hippocampal CA3 neurons of rats. CHEMOSPHERE 2017; 184:337-346. [PMID: 28605704 DOI: 10.1016/j.chemosphere.2017.05.158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 05/23/2017] [Accepted: 05/28/2017] [Indexed: 06/07/2023]
Abstract
4,5-Dichloro-2-octyl-4-isothiazolin-3-one (DCOIT) is an alternative to organotin antifoulants, such as tributyltin and triphenyltin. Since DCOIT is found in harbors, bays, and coastal areas worldwide, this chemical compound may have some impacts on ecosystems. To determine whether DCOIT possesses neurotoxic activity by modifying synaptic transmission, we examined the effects of DCOIT on synaptic transmission in a 'synaptic bouton' preparation of rat brain. DCOIT at concentrations of 0.03-1 μM increased the amplitudes of evoked synaptic currents mediated by GABA and glutamate, while it reduced the amplitudes of these currents at 3-10 μM. However, the currents elicited by exogenous applications of GABA and glutamate were not affected by DCOIT. DCOIT at 1-10 μM increased the frequency of spontaneous synaptic currents mediated by GABA. It also increased the frequency of glutamate-mediated spontaneous currents at0.3-10 μM. The frequencies of miniature synaptic currents mediated by GABA and glutamate, observed in the presence of tetrodotoxin under external Ca2+-free conditions, were increased by 10 μM DCOIT. With the repetitive applications of DCOIT, the frequency of miniature synaptic currents mediated by glutamate was not increased by the second and third applications of DCOIT. Voltage-dependent Ca2+ channels were not affected by DCOIT, but DCOIT slowed the inactivation of voltage-dependent Na+ channels. These results suggest that DCOIT increases Ca2+ release from intracellular Ca2+ stores, resulting in the facilitation of both action potential-dependent and spontaneous neurotransmission, possibly leading to neurotoxicity.
Collapse
Affiliation(s)
- Masahito Wakita
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryokai, Kumamoto Kinoh Hospital, Kumamoto, 860-8518, Japan; Research Division for Life Science, Kumamoto Health Science University, Kumamoto, 861-5598, Japan.
| | - Kiyomitsu Shoudai
- Research Division for Life Science, Kumamoto Health Science University, Kumamoto, 861-5598, Japan
| | - Yasuo Oyama
- Laboratory of Cellular Signaling, Faculty of Biosciences and Bioindustry, Tokushima University, Tokushima, 770-8513, Japan.
| | - Norio Akaike
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryokai, Kumamoto Kinoh Hospital, Kumamoto, 860-8518, Japan; Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
| |
Collapse
|
8
|
Fu B, Wang Y, Yang H, Yu T. Effects of Etomidate on GABAergic and Glutamatergic Transmission in Rat Thalamocortical Slices. Neurochem Res 2016; 41:3181-3191. [PMID: 27561291 DOI: 10.1007/s11064-016-2042-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 08/10/2016] [Accepted: 08/22/2016] [Indexed: 12/14/2022]
Abstract
Although accumulative evidence indicates that the thalamocortical system is an important target for general anesthetics, the underlying mechanisms of anesthetic action on thalamocortical neurotransmission are not fully understood. The aim of the study is to explore the action of etomidate on glutamatergic and GABAergic transmission in rat thalamocortical slices by using whole cell patch-clamp recording. We found that etomidate mainly prolonged the decay time of spontaneous GABAergic inhibitory postsynaptic currents (sIPSCs), without changing the frequency. Furthermore, etomidate not only prolonged the decay time of miniature inhibitory postsynaptic currents (mIPSCs) but also increased the amplitude. On the other hand, etomidate significantly decreased the frequency of spontaneous glutamatergic excitatory postsynaptic currents (sEPSCs), without altering the amplitude or decay time in the absence of bicuculline. When GABAA receptors were blocked using bicuculline, the effects of etomidate on sEPSCs were mostly eliminated. These results suggest that etomidate enhances GABAergic transmission mainly through postsynaptic mechanism in thalamocortical neuronal network. Etomidate attenuates glutamatergic transmission predominantly through presynaptic action and requires presynaptic GABAA receptors involvement.
Collapse
Affiliation(s)
- Bao Fu
- Department of Critical Care Medicine, Affiliated Hospital of Zunyi Medical College, Zunyi, Guizhou, China
| | - Yuan Wang
- Department of Anesthesiology, Affiliated Hospital of Zunyi Medical College, Zunyi, Guizhou, China
| | - Hao Yang
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical College, Dalian road 149, Zunyi, 563000, Guizhou, China
| | - Tian Yu
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical College, Dalian road 149, Zunyi, 563000, Guizhou, China.
| |
Collapse
|
9
|
ZHANG JJ, LIU XD, YU LC. Influences of Morphine on the Spontaneous and Evoked Excitatory Postsynaptic Currents in Lateral Amygdala of Rats. Physiol Res 2016; 65:165-9. [DOI: 10.33549/physiolres.933027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Acute morphine exposure induces antinociceptive activity, but the underlying mechanisms in the central nervous system are unclear. Using whole-cell patch clamp recordings, we explore the role of morphine in the modulation of excitatory synaptic transmission in lateral amygdala neurons of rats. The results demonstrate that perfusion of 10 μM of morphine to the lateral amygdala inhibits the discharge frequency significantly. We further find that there are no significant influences of morphine on the amplitude of spontaneous excitatory postsynaptic currents (sEPSCs). Interestingly, morphine shows no marked influence on the evoked excitatory postsynaptic currents (eEPSCs) in the lateral amygdala neurons. These results indicate that acute morphine treatment plays an important role in the modulation on the excitatory synaptic transmission in lateral amygdala neurons of rats.
Collapse
Affiliation(s)
| | | | - L.-C. YU
- State Key Laboratory of Biomembrane and Membrane Biotechnology and Laboratory of Neurobiology, College of Life Sciences, Peking University, Beijing, People’s Republic of China
| |
Collapse
|
10
|
The plastic neurotransmitter phenotype of the hippocampal granule cells and of the moss in their messy fibers. J Chem Neuroanat 2015; 73:9-20. [PMID: 26703784 DOI: 10.1016/j.jchemneu.2015.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 10/29/2015] [Accepted: 11/03/2015] [Indexed: 01/09/2023]
Abstract
The granule cells (GCs) and their axons, the mossy fibers (MFs), make synapses with interneurons in the hilus and CA3 area of the hippocampus and with pyramidal cells of CA3, each with distinct anatomical and functional characteristics. Many features of synaptic communication observed at the MF synapses are not usually observed in most cortical synapses, and thus have drawn the attention of many groups studying different aspects of the transmission of information. One particular aspect of the GCs, that makes their study unique, is that they express a dual glutamatergic-GABAergic phenotype and several groups have contributed to the understanding of how two neurotransmitters of opposing actions can act on a single target when simultaneously released. Indeed, the GCs somata and their mossy fibers express in a regulated manner glutamate and GABA, GAD, VGlut and VGAT, all markers of both phenotypes. Finally, their activation provokes both glutamate-R-mediated and GABA-R-mediated synaptic responses in the postsynaptic cell targets and even in the MFs themselves. The developmental and activity-dependent expression of these phenotypes seems to follow a "logical" way to maintain an excitation-inhibition balance of the dentate gyrus-to-CA3 communication.
Collapse
|
11
|
Wakita M, Kotani N, Akaike N. Effects of propofol on glycinergic neurotransmission in a single spinal nerve synapse preparation. Brain Res 2015; 1631:147-56. [PMID: 26616339 DOI: 10.1016/j.brainres.2015.11.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 11/13/2015] [Accepted: 11/17/2015] [Indexed: 12/30/2022]
Abstract
The effects of the intravenous anesthetic, propofol, on glycinergic transmission and on glycine receptor-mediated whole-cell currents (IGly) were examined in the substantia gelatinosa (SG) neuronal cell body, mechanically dissociated from the rat spinal cord. This "synaptic bouton" preparation, which retains functional native nerve endings, allowed us to evaluate glycinergic inhibitory postsynaptic currents (IPSCs) and whole-cell currents in a preparation in which experimental solution could rapidly access synaptic terminals. Synaptic IPSCs were measured as spontaneous (s) and evoked (e) IPSCs. The eIPSCs were elicited by applying paired-pulse focal electrical stimulation, while IGly was evoked by a bath application of glycine. A concentration-dependent enhancement of IGly was observed for ≥10µM propofol. Propofol (≥3µM) significantly increased the frequency of sIPSCs and prolonged the decay time without altering the current amplitude. However, propofol (≥3µM) also significantly increased the mean amplitude of eIPSCs and decreased the failure rate (Rf). A decrease in the paired-pulse ratio (PPR) was noted at higher concentrations (≥10µM). The decay time of eIPSCs was prolonged only at the maximum concentration tested (30µM). Propofol thus acts at both presynaptic glycine release machinery and postsynaptic glycine receptors. At clinically relevant concentrations (<1μM) there was no effect on IGly, sIPSCs or eIPSCs suggesting that at anesthetic doses propofol does not affect inhibitory glycinergic synapses in the spinal cord.
Collapse
Affiliation(s)
- Masahito Wakita
- Research Division for Clinical Pharmacology, Medical Corporation, JyuryoGroup, Kumamoto Kinoh Hospital, 6-8-1 Yamamuro, Kitaku, Kumamoto 860-8518, Japan; Research Division for Life Science, Kumamoto Health Science University, 325 Izumi-machi, Kitaku, Kumamoto 861-5598, Japan
| | - Naoki Kotani
- Research Division of Neurophysiology, Kitamoto Hospital, 3-7-6 Kawarasone, Koshigaya 343-0821, Japan
| | - Norio Akaike
- Research Division for Clinical Pharmacology, Medical Corporation, JyuryoGroup, Kumamoto Kinoh Hospital, 6-8-1 Yamamuro, Kitaku, Kumamoto 860-8518, Japan; Research Division of Neurophysiology, Kitamoto Hospital, 3-7-6 Kawarasone, Koshigaya 343-0821, Japan; Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan.
| |
Collapse
|
12
|
Betelli C, MacDermott AB, Bardoni R. Transient, activity dependent inhibition of transmitter release from low threshold afferents mediated by GABAA receptors in spinal cord lamina III/IV. Mol Pain 2015; 11:64. [PMID: 26463733 PMCID: PMC4605127 DOI: 10.1186/s12990-015-0067-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/06/2015] [Indexed: 12/20/2022] Open
Abstract
Background Presynaptic GABAA receptors (GABAARs) located on central terminals of low threshold afferent fibers are thought to be involved in the processing of touch and possibly in the generation of tactile allodynia in chronic pain. These GABAARs mediate primary afferent depolarization (PAD) and modulate transmitter release. The objective of this study was to expand our understanding of the presynaptic inhibitory action of GABA released onto primary afferent central terminals following afferent stimulation. Results We recorded evoked postsynaptic excitatory responses (eEPSCs and eEPSPs) from lamina III/IV neurons in spinal cord slices from juvenile rats (P17–P23, either sex), while stimulating dorsal roots. We investigated time and activity dependent changes in glutamate release from low threshold A fibers and the impact of these changes on excitatory drive. Blockade of GABAARs by gabazine potentiated the second eEPSC during a train of four afferent stimuli in a large subset of synapses. This resulted in a corresponding increase of action potential firing after the second stimulus. The potentiating effect of gabazine was due to inhibition of endogenously activated presynaptic GABAARs, because it was not prevented by the blockade of postsynaptic GABAARs through intracellular perfusion of CsF. Exogenous activation of presynaptic GABAARs by muscimol depressed evoked glutamate release at all synapses and increased paired pulse ratio (PPR). Conclusions These observations suggest that afferent driven release of GABA onto low threshold afferent terminals is most effective following the first action potential in a train and serves to suppress the initial strong excitatory drive onto dorsal horn circuitry.
Collapse
Affiliation(s)
- Chiara Betelli
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via Campi, 287, 41125, Modena, Italy.
| | - Amy B MacDermott
- Departments of Physiology and Cellular Biophysics, Neuroscience, Columbia University, 630 W. 168th Street, New York, NY, 10032, USA.
| | - Rita Bardoni
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via Campi, 287, 41125, Modena, Italy.
| |
Collapse
|
13
|
Wakita M, Kotani N, Yamaga T, Akaike N. Nitrous oxide directly inhibits action potential-dependent neurotransmission from single presynaptic boutons adhering to rat hippocampal CA3 neurons. Brain Res Bull 2015; 118:34-45. [PMID: 26343381 DOI: 10.1016/j.brainresbull.2015.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 08/26/2015] [Accepted: 09/01/2015] [Indexed: 11/16/2022]
Abstract
We evaluated the effects of N2O on synaptic transmission using a preparation of mechanically dissociated rat hippocampal CA3 neurons that allowed assays of single bouton responses evoked from native functional nerve endings. We studied the effects of N2O on GABAA, glutamate, AMPA and NMDA receptor-mediated currents (IGABA, IGlu, IAMPA and INMDA) elicited by exogenous application of GABA, glutamate, (S)-AMPA, and NMDA and spontaneous, miniature, and evoked GABAergic inhibitory and glutamatergic excitatory postsynaptic current (sIPSC, mIPSC, eIPSC, sEPSC, mEPSC and eEPSC) in mechanically dissociated CA3 neurons. eIPSC and eEPSC were evoked by focal electrical stimulation of a single bouton. Administration of 70% N2O altered neither IGABA nor the frequency and amplitude of both sIPSCs and mIPSCs. In contrast, N2O decreased the amplitude of eIPSCs, while increasing failure rates (Rf) and paired-pulse ratios (PPR) in a concentration-dependent manner. On the other hand, N2O decreased IGlu, IAMPA and INMDA. Again N2O did not change the frequency and amplitude of either sEPSCs of mEPSCs. N2O also decreased amplitudes of eEPSCs with increased Rf and PPR. The decay phases of all synaptic responses were unchanged. The present results indicated that N2O inhibits the activation of AMPA/KA and NMDA receptors and also that N2O preferentially depress the action potential-dependent GABA and glutamate releases but had little effects on spontaneous and miniature releases.
Collapse
Affiliation(s)
- Masahito Wakita
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryo Group, Kumamoto Kinoh Hospital, 6-8-1 Yamamuro, Kitaku, Kumamoto 860-8518, Japan; Research Division for Life Science, Kumamoto Health Science University, 325 Izumi-machi, Kitaku, Kumamoto 861-5598, Japan
| | - Naoki Kotani
- Research Division of Neurophysiology, Kitamoto Hospital, 3-7-6 Kawarasone, Koshigaya, Saitama 343-0821, Japan
| | - Toshitaka Yamaga
- Research Division for Life Science, Kumamoto Health Science University, 325 Izumi-machi, Kitaku, Kumamoto 861-5598, Japan
| | - Norio Akaike
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryo Group, Kumamoto Kinoh Hospital, 6-8-1 Yamamuro, Kitaku, Kumamoto 860-8518, Japan; Research Division for Life Science, Kumamoto Health Science University, 325 Izumi-machi, Kitaku, Kumamoto 861-5598, Japan; Research Division of Neurophysiology, Kitamoto Hospital, 3-7-6 Kawarasone, Koshigaya, Saitama 343-0821, Japan.
| |
Collapse
|
14
|
Wakita M, Nagami H, Takase Y, Nakanishi R, Kotani N, Akaike N. Modifications of excitatory and inhibitory transmission in rat hippocampal pyramidal neurons by acute lithium treatment. Brain Res Bull 2015; 117:39-44. [PMID: 26247839 DOI: 10.1016/j.brainresbull.2015.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 07/24/2015] [Accepted: 07/28/2015] [Indexed: 11/25/2022]
Abstract
The acute effects of high-dose Li(+) treatment on glutamatergic and GABAergic transmissions were studied in the "synaptic bouton" preparation of isolated rat hippocampal pyramidal neurons by using focal electrical stimulation. Both action potential-dependent glutamatergic excitatory and GABAergic inhibitory postsynaptic currents (eEPSC and eIPSC, respectively) were dose-dependently inhibited in the external media containing 30-150 mM Li(+), but the sensitivity for Li(+) was greater tendency for eEPSCs than for eIPSCs. When the effects of Li(+) on glutamate or GABAA receptor-mediated whole-cell responses (IGlu and IGABA) elicited by an exogenous application of glutamate or GABA were examined in the postsynaptic soma membrane of CA3 neurons, Li(+) slightly inhibited both IGlu and IGABA at the 150 mM Li(+) concentration. Present results suggest that acute treatment with high concentrations of Li(+) acts preferentially on presynaptic terminals, and that the Li(+)-induced inhibition may be greater for excitatory than for inhibitory transmission.
Collapse
Affiliation(s)
- Masahito Wakita
- Research Division for Clinical Pharmacology, Medical Corporation, Juryokai, Kumamoto Kinoh Hospital, 6-8-1, Yamamuro, Kita-ku, Kumamoto 860-8518, Japan
| | - Hideaki Nagami
- Research Division for Clinical Pharmacology, Medical Corporation, Juryokai, Kumamoto Kinoh Hospital, 6-8-1, Yamamuro, Kita-ku, Kumamoto 860-8518, Japan
| | - Yuko Takase
- Research Division for Clinical Pharmacology, Medical Corporation, Juryokai, Kumamoto Kinoh Hospital, 6-8-1, Yamamuro, Kita-ku, Kumamoto 860-8518, Japan
| | - Ryoji Nakanishi
- Research Division for Clinical Pharmacology, Medical Corporation, Juryokai, Kumamoto Kinoh Hospital, 6-8-1, Yamamuro, Kita-ku, Kumamoto 860-8518, Japan
| | - Naoki Kotani
- Research Division of Neurophysiology, Kitamoto Hospital, 3-7-6, Kawarasone, Koshigaya 343-0821, Japan
| | - Norio Akaike
- Research Division for Clinical Pharmacology, Medical Corporation, Juryokai, Kumamoto Kinoh Hospital, 6-8-1, Yamamuro, Kita-ku, Kumamoto 860-8518, Japan; Research Division of Neurophysiology, Kitamoto Hospital, 3-7-6, Kawarasone, Koshigaya 343-0821, Japan; Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Chuo-ku, Kumamoto 862-0973, Japan.
| |
Collapse
|
15
|
Wakita M, Kotani N, Shoudai K, Yamaga T, Akaike N. Modulation of inhibitory and excitatory fast neurotransmission in the rat CNS by heavy water (D2O). J Neurophysiol 2015; 114:1109-18. [PMID: 26019316 DOI: 10.1152/jn.00801.2014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 05/26/2015] [Indexed: 11/22/2022] Open
Abstract
The effects of heavy water (deuterium oxide, D2O) on GABAergic and glutamatergic spontaneous and evoked synaptic transmission were investigated in acute brain slice and isolated "synaptic bouton" preparations of rat hippocampal CA3 neurons. The substitution of D2O for H2O reduced the frequency and amplitude of GABAergic spontaneous inhibitory postsynaptic currents (sIPSCs) in a concentration-dependent manner but had no effect on glutamatergic spontaneous excitatory postsynaptic currents (sEPSCs). In contrast, for evoked synaptic responses in isolated neurons, the amplitude of both inhibitory and excitatory postsynaptic currents (eIPSCs and eEPSCs) was decreased in a concentration-dependent manner. This was associated with increases of synaptic failure rate (Rf) and paired-pulse ratio (PPR). The effect was larger for eIPSCs compared with eEPSCs. These results clearly indicate that D2O acts differently on inhibitory and excitatory neurotransmitter release machinery. Furthermore, D2O significantly suppressed GABAA receptor-mediated whole cell current (IGABA) but did not affect glutamate receptor-mediated whole cell current (IGlu). The combined effects of D2O at both the pre- and postsynaptic sites may explain the greater inhibition of eIPSCs compared with eEPSCs. Finally, D2O did not enhance or otherwise affect the actions of the general anesthetics nitrous oxide and propofol on spontaneous or evoked GABAergic and glutamatergic neurotransmissions, or on IGABA and IGlu. Our results suggest that previously reported effects of D2O to mimic and/or modulate anesthesia potency result from mechanisms other than modulation of GABAergic and glutamatergic neurotransmission.
Collapse
Affiliation(s)
- Masahito Wakita
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryo Group, Kumamoto Kinoh Hospital, Kitaku, Kumamoto, Japan; Research Division for Life Science, Kumamoto Health Science University, Kitaku, Kumamoto, Japan; and
| | - Naoki Kotani
- Research Division of Neurophysiology, Kitamoto Hospital, Koshigaya, Japan
| | - Kiyomitsu Shoudai
- Research Division for Life Science, Kumamoto Health Science University, Kitaku, Kumamoto, Japan; and
| | - Toshitaka Yamaga
- Research Division for Life Science, Kumamoto Health Science University, Kitaku, Kumamoto, Japan; and
| | - Norio Akaike
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryo Group, Kumamoto Kinoh Hospital, Kitaku, Kumamoto, Japan; Research Division for Life Science, Kumamoto Health Science University, Kitaku, Kumamoto, Japan; and Research Division of Neurophysiology, Kitamoto Hospital, Koshigaya, Japan
| |
Collapse
|
16
|
Abstract
Schizophrenia is a complex mental health disorder with positive, negative and cognitive symptom domains. Approximately one third of patients are resistant to currently available medication. New therapeutic targets and a better understanding of the basic biological processes that drive pathogenesis are needed in order to develop therapies that will improve quality of life for these patients. Several drugs that act on neurotransmitter systems in the brain have been suggested to model aspects of schizophrenia in animals and in man. In this paper, we selectively review findings from dopaminergic, glutamatergic, serotonergic, cannabinoid, GABA, cholinergic and kappa opioid pharmacological drug models to evaluate their similarity to schizophrenia. Understanding the interactions between these different neurotransmitter systems and their relationship with symptoms will be an important step towards building a coherent hypothesis for the pathogenesis of schizophrenia.
Collapse
Affiliation(s)
- Hannah Steeds
- Imperial College London, Division of Brain Sciences, Du Cane Road, London W12 0NN, UK
| | | | - James M Stone
- King's College London, Institute of Psychiatry Psychology and Neuroscience, De Crespigny Park, London SE5 8AF, UK, Imperial College London, Division of Brain Sciences, Du Cane Road, London W12 0NN, UK
| |
Collapse
|
17
|
Wakita M, Kotani N, Kogure K, Akaike N. Inhibition of excitatory synaptic transmission in hippocampal neurons by levetiracetam involves Zn²⁺-dependent GABA type A receptor-mediated presynaptic modulation. J Pharmacol Exp Ther 2013; 348:246-59. [PMID: 24259680 DOI: 10.1124/jpet.113.208751] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Levetiracetam (LEV) is an antiepileptic drug with a unique but as yet not fully resolved mechanism of action. Therefore, by use of a simplified rat-isolated nerve-bouton preparation, we have investigated how LEV modulates glutamatergic transmission from mossy fiber terminals to hippocampal CA3 neurons. Action potential-evoked excitatory postsynaptic currents (eEPSCs) were recorded using a conventional whole-cell patch-clamp recording configuration in voltage-clamp mode. The antiepileptic drug phenytoin decreased glutamatergic eEPSCs in a concentration-dependent fashion by inhibiting voltage-dependent Na⁺ and Ca²⁺ channel currents. In contrast, LEV had no effect on eEPSCs or voltage-dependent Na⁺ or Ca²⁺ channel currents. Activation of presynaptic GABA type A (GABA(A)) receptors by muscimol induced presynaptic inhibition of eEPSCs, resulting from depolarization block. Low concentrations of Zn²⁺, which had no effect on eEPSCs, voltage-dependent Na⁺ or Ca²⁺ channel currents, or glutamate receptor-mediated whole cell currents, reduced the muscimol-induced presynaptic inhibition. LEV applied in the continuous presence of 1 µM muscimol and 1 µM Zn²⁺ reversed this Zn²⁺ modulation on eEPSCs. The antagonizing effect of LEV on Zn²⁺-induced presynaptic GABA(A) receptor inhibition was also observed with the Zn²⁺ chelators Ca-EDTA and RhodZin-3. Our results clearly show that LEV removes the Zn²⁺-induced suppression of GABA(A)-mediated presynaptic inhibition, resulting in a presynaptic decrease in glutamate-mediated excitatory transmission. Our results provide a novel mechanism by which LEV may inhibit neuronal activity.
Collapse
Affiliation(s)
- Masahito Wakita
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryokai, Kumamoto Kinoh Hospital, Kumamoto, Japan (M.W., N.A.); Research Division for Life Science, Kumamoto Health Science University, Kumamoto, Japan (M.W., N.A.); Research Division of Neurophysiology, Kitamoto Hospital, Koshigaya, Japan (N.K., N.A); and Kogure Medical Clinic, Chouseikai Medical Corporation, Fukaya City, Saitama, Japan (K.K.)
| | | | | | | |
Collapse
|
18
|
Wakita M, Kotani N, Nonaka K, Shin MC, Akaike N. Effects of propofol on GABAergic and glutamatergic transmission in isolated hippocampal single nerve-synapse preparations. Eur J Pharmacol 2013; 718:63-73. [DOI: 10.1016/j.ejphar.2013.09.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 08/26/2013] [Accepted: 09/04/2013] [Indexed: 01/12/2023]
|
19
|
Kato K, Akaike N, Kohda T, Torii Y, Goto Y, Harakawa T, Ginnaga A, Kaji R, Kozaki S. Botulinum neurotoxin A2 reduces incidence of seizures in mouse models of temporal lobe epilepsy. Toxicon 2013; 74:109-15. [PMID: 23954512 DOI: 10.1016/j.toxicon.2013.07.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 07/13/2013] [Accepted: 07/30/2013] [Indexed: 12/01/2022]
Abstract
Temporal lobe epilepsy often shows pharmacoresistance, and well-known anti-convulsants sometimes are not effective for blocking chronic seizures. Botulinum neurotoxins are metalloproteases that act on presynaptic proteins and inhibit neurotransmitter release in both the peripheral and central nerve systems. That is why neurotoxins may elicit an effect for the restraint of the seizures. Meanwhile, it has been suggested that a property and the stability of neurotoxin activities differ among the types A-G, in which type A neurotoxin (ANTX) is, especially, the most stable and can continue having activity for a long term. The present study therefore investigated the effects of hippocampal injections of A2NTX on seizures derived in TLE model mice, received repeated kindling stimulations in the amygdala. The injections induced complete disappearance of grand mal seizures in half of the population of amygdala kindled mice for 4 days. The injections also induced reduction of the evoked seizure level significantly for at least 18 days after injections. Taken together, these results suggest that A2NTX prevents from epileptic seizures, proposing that A2NTX is available as a new antiepileptic reagent.
Collapse
Affiliation(s)
- Keiko Kato
- Faculty of Life Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Iwata S, Wakita M, Shin MC, Fukuda A, Akaike N. Modulation of allopregnanolone on excitatory transmitters release from single glutamatergic terminal. Brain Res Bull 2013; 93:39-46. [DOI: 10.1016/j.brainresbull.2012.11.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 11/02/2012] [Accepted: 11/05/2012] [Indexed: 10/27/2022]
|
21
|
Shin MC, Wakita M, Iwata S, Nonaka K, Kotani N, Akaike N. Comparative effects of pentobarbital on spontaneous and evoked transmitter release from inhibitory and excitatory nerve terminals in rat CA3 neurons. Brain Res Bull 2012; 90:10-8. [PMID: 23026118 DOI: 10.1016/j.brainresbull.2012.09.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 09/14/2012] [Accepted: 09/19/2012] [Indexed: 10/27/2022]
Abstract
Pentobarbital (PB) modulates GABA(A) receptor-mediated postsynaptic responses through various mechanisms, and can directly activate the channel at higher doses. These channels exist both pre- and postsynaptically, and on the soma outside the synapse. PB also inhibits voltage-dependent Na⁺ and Ca²⁺ channels to decrease excitatory synaptic transmission. Just how these different sites of action combine to contribute to the overall effects of PB on inhibitory and excitatory synaptic transmission is less clear. To compare these pre- and postsynaptic actions of PB, we used a 'synaptic bouton' preparation of isolated rat hippocampal CA3 pyramidal neurons where we could measure in single neurons the effects of PB on spontaneous and single bouton evoked GABAergic inhibitory and glutamatergic excitatory postsynaptic currents (sIPSCs, sEPSCs, eIPSCs and eEPSCs), respectively. Low (sedative) concentrations (3-10 μM) of PB increased the frequency and amplitude of sIPSCs and sEPSCs, and also presynaptically increased the amplitude of both eIPSCs and eEPSCs. There was no change in current kinetics at this low concentration. At higher concentrations (30-300 μM), PB decreased the frequency, and increased the amplitude of sIPSCs, and presynaptically decreased the amplitude of eIPSCs. The current decay phase of sIPSCs and eIPSCs was increased. An increase in both frequency and amplitude was seen for sEPSCs, while the eIPSCs was also decreased by a bicuculline-sensitive presynaptic effect. The results confirm the multiple sites of action of PB on inhibitory and excitatory transmission and demonstrate that the most sensitive site of action is on transmitter release, via effects on presynaptic GABA(A) receptors. At low concentrations, however, both glutamate and GABA release is similarly enhanced, making the final effects on neuronal excitability difficult to predict and dependent on the particular systems involved and/or on subtle differences in susceptibility amongst individuals. At higher concentrations, release of both transmitters is decreased, while the postsynaptic effects to increase IPSPs and decrease EPSCs would be expected to both results in reduced neuronal excitability.
Collapse
Affiliation(s)
- Min-Chul Shin
- Research Division for Life Sciences, Kumamoto Health Science University, Kumamoto 861-5598, Japan
| | | | | | | | | | | |
Collapse
|
22
|
Effects of halothane on GABAergic and glutamatergic transmission in isolated hippocampal nerve-synapse preparations. Brain Res 2012; 1473:9-18. [DOI: 10.1016/j.brainres.2012.07.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 07/17/2012] [Accepted: 07/18/2012] [Indexed: 01/31/2023]
|
23
|
The effects of volatile anesthetics on synaptic and extrasynaptic GABA-induced neurotransmission. Brain Res Bull 2012; 93:69-79. [PMID: 22925739 DOI: 10.1016/j.brainresbull.2012.08.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/17/2012] [Accepted: 08/01/2012] [Indexed: 02/02/2023]
Abstract
Examination of volatile anesthetic actions at single synapses provides more direct information by reducing interference by surrounding tissue and extrasynaptic modulation. We examined how volatile anesthetics modulate GABA release by measuring spontaneous or miniature GABA-induced inhibitory postsynaptic currents (mIPSCs, sIPSCs) or by measuring action potential-evoked IPSCs (eIPSCs) at individual synapses. Halothane increased both the amplitude and frequency of sIPSCs. Isoflurane and enflurane increased mIPSC frequency while sevoflurane had no effect. These anesthetics did not alter mIPSC amplitudes. Halothane increased the amplitude of eIPSCs, with a decrease in failure rate (Rf) and paired-pulse ratio. In contrast, isoflurane and enflurane decreased the eIPSC amplitude and increased Rf, while sevoflurane decreased the eIPSC amplitude without affecting Rf. Volatile anesthetics did not change kinetics except for sevoflurane, suggesting that presynaptic mechanisms dominate changes in neurotransmission. Each anesthetic showed somewhat different GABA-induced response and these results suggest that GABA-induced synaptic transmission cannot have a uniformly common site of action as suggested for volatile anesthetics. In contrast, all volatile anesthetics concentration-dependently enhanced the GABA-induced extrasynaptic currents. Extrasynaptic receptors containing α4 and α5 subunits are reported to have high sensitivities to volatile anesthetics. Also, inhibition of GABA uptake by volatile anesthetics results in higher extracellular GABA concentration, which may lead to prolonged activation of extrasynaptic GABAA receptors. The extrasynaptic GABA-induced receptors may be major site of volatile anesthetic-induced neurotransmission. This article is part of a Special Issue entitled 'Extrasynaptic ionotropic receptors'.
Collapse
|
24
|
Wakita M, Shin MC, Iwata S, Nonaka K, Akaike N. Effects of ethanol on GABA(A) receptors in GABAergic and glutamatergic presynaptic nerve terminals. J Pharmacol Exp Ther 2012; 341:809-19. [PMID: 22434676 DOI: 10.1124/jpet.111.189126] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Ethanol (EtOH) has a number of behavioral effects, including intoxication, amnesia, and/or sedation, that are thought to relate to the activation of GABA(A) receptors. However, GABA(A) receptors at different cellular locations have different sensitivities to EtOH. The present study used the "synaptic bouton" preparation where we could stimulate nerve endings on mechanically dissociated single rat hippocampal CA1 and CA3 pyramidal neurons and investigate the effects of EtOH on presynaptic and postsynaptic GABA(A) receptors. Low concentrations of EtOH (10 mM) had no effect on postsynaptic GABA(A) and glutamate receptors or voltage-dependent Na(+) and Ca(2+) channels. Higher concentrations (≥100 mM) could significantly inhibit these current responses. EtOH at 10 mM had no direct effect on inhibitory postsynaptic currents (IPSCs) and excitatory postsynaptic currents (EPSCs) evoked by focal stimulation of single boutons [evoked IPSCs (eIPSCs) and evoked EPSCs (eEPSCs)]. However, coapplication of 10 mM EtOH with muscimol decreased the amplitude of eIPSCs and eEPSCs and increased their paired-pulse ratio. The effects on eEPSCs were reversed by bicuculline. Coapplication of muscimol and EtOH significantly increased the frequency of spontaneous IPSCs and EPSCs. The EtOH effects on the postsynaptic responses and eEPSCs were similar in neurons from neonatal and mature rats. These results revealed that low concentrations of EtOH can potentiate the activation of presynaptic GABA(A) receptors to inhibit evoked GABA and glutamate release. These results indicate a high sensitivity of presynaptic GABA(A) receptor to EtOH, which needs to be accounted for when considering the cellular mechanisms of EtOH's physiological responses.
Collapse
Affiliation(s)
- Masahito Wakita
- Research Division for Life Sciences, Kumamoto Health Science University, 325 Izumimachi, Kumamoto, 861-5598, Japan
| | | | | | | | | |
Collapse
|
25
|
Yamaga T, Aou S, Shin MC, Wakita M, Akaike N. Neurotoxin A2NTX Blocks Fast Inhibitory and Excitatory Transmitter Release From Presynaptic Terminals. J Pharmacol Sci 2012; 118:75-81. [DOI: 10.1254/jphs.11124fp] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 11/09/2011] [Indexed: 10/14/2022] Open
|
26
|
Synergic effect of diazepam and muscimol via presynaptic GABAA receptors on glutamatergic evoked EPSCs. Brain Res 2011; 1416:1-9. [DOI: 10.1016/j.brainres.2011.07.054] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2011] [Revised: 07/25/2011] [Accepted: 07/27/2011] [Indexed: 11/21/2022]
|
27
|
Different effects of α-chloralose on spontaneous and evoked GABA release in rat hippocampal CA1 neurons. Brain Res Bull 2011; 85:180-8. [DOI: 10.1016/j.brainresbull.2011.03.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 03/18/2011] [Accepted: 03/22/2011] [Indexed: 01/02/2023]
|