Selective depression by general anesthetics of glutamate versus GABA release from isolated cortical nerve terminals
- PMID:12604696
- DOI: 10.1124/jpet.102.044685
Selective depression by general anesthetics of glutamate versus GABA release from isolated cortical nerve terminals
Abstract
The role of presynaptic mechanisms in general anesthetic depression of excitatory glutamatergic neurotransmission and facilitation of GABA-mediated inhibitory neurotransmission is unclear. A dual isotope method allowed simultaneous comparisons of the effects of a representative volatile (isoflurane) and intravenous (propofol) anesthetic on the release of glutamate and GABA from isolated rat cerebrocortical nerve terminals (synaptosomes). Synaptosomes were prelabeled with L-[(3)H]glutamate and [(14)C]GABA, and release was determined by superfusion with pulses of 30 mM K(+) or 1 mM 4-aminopyridine (4AP) in the absence or presence of 1.9 mM free Ca(2+). Isoflurane maximally inhibited Ca(2+)-dependent 4AP-evoked L-[(3)H]glutamate release (99 +/- 8% inhibition) to a greater extent than [(14)C]GABA release (74 +/- 6% inhibition; P = 0.023). Greater inhibition of L-[(3)H]glutamate versus [(14)C]GABA release was also observed for the Na(+) channel antagonists tetrodotoxin (99 +/- 4 versus 63 +/- 5% inhibition; P < 0.001) and riluzole (84 +/- 5 versus 52 +/- 12% inhibition; P = 0.041). Propofol did not differ in its maximum inhibition of Ca(2+)-dependent 4AP-evoked L-[(3)H]glutamate release (76 +/- 12% inhibition) compared with [(14)C]GABA (84 +/- 31% inhibition; P = 0.99) release. Neither isoflurane (1 mM) nor propofol (15 microM) affected K(+)-evoked release, consistent with a molecular target upstream of the synaptic vesicle exocytotic machinery or voltage-gated Ca(2+) channels coupled to transmitter release. These findings support selective presynaptic depression of excitatory versus inhibitory neurotransmission by clinical concentrations of isoflurane, probably as a result of Na(+) channel blockade.
Similar articles
- Volatile anesthetic effects on glutamate versus GABA release from isolated rat cortical nerve terminals: 4-aminopyridine-evoked release.Westphalen RI, Hemmings HC Jr.Westphalen RI, et al.J Pharmacol Exp Ther. 2006 Jan;316(1):216-23. doi: 10.1124/jpet.105.090662. Epub 2005 Sep 20.J Pharmacol Exp Ther. 2006.PMID:16174800
- Volatile anesthetic effects on glutamate versus GABA release from isolated rat cortical nerve terminals: basal release.Westphalen RI, Hemmings HC Jr.Westphalen RI, et al.J Pharmacol Exp Ther. 2006 Jan;316(1):208-15. doi: 10.1124/jpet.105.090647. Epub 2005 Sep 20.J Pharmacol Exp Ther. 2006.PMID:16174801
- Isoflurane and propofol inhibit voltage-gated sodium channels in isolated rat neurohypophysial nerve terminals.Ouyang W, Wang G, Hemmings HC Jr.Ouyang W, et al.Mol Pharmacol. 2003 Aug;64(2):373-81. doi: 10.1124/mol.64.2.373.Mol Pharmacol. 2003.PMID:12869642
- The Role of GABA Receptors in Anesthesia and Sedation: An Updated Review.Philip AB, Brohan J, Goudra B.Philip AB, et al.CNS Drugs. 2025 Jan;39(1):39-54. doi: 10.1007/s40263-024-01128-6. Epub 2024 Oct 27.CNS Drugs. 2025.PMID:39465449Free PMC article.Review.
- Membrane excitability and secretion from peptidergic nerve terminals.Branchaw JL, Hsu SF, Jackson MB.Branchaw JL, et al.Cell Mol Neurobiol. 1998 Feb;18(1):45-63. doi: 10.1023/a:1022523109900.Cell Mol Neurobiol. 1998.PMID:9524729Free PMC article.Review.
Cited by
- A Common Human Brain-Derived Neurotrophic Factor Polymorphism Leads to Prolonged Depression of Excitatory Synaptic Transmission by Isoflurane in Hippocampal Cultures.Williams RA, Johnson KW, Lee FS, Hemmings HC Jr, Platholi J.Williams RA, et al.Front Mol Neurosci. 2022 Jun 23;15:927149. doi: 10.3389/fnmol.2022.927149. eCollection 2022.Front Mol Neurosci. 2022.PMID:35813074Free PMC article.
- Discrimination of auditory stimuli during isoflurane anesthesia.Rojas MJ, Navas JA, Greene SA, Rector DM.Rojas MJ, et al.Comp Med. 2008 Oct;58(5):454-7.Comp Med. 2008.PMID:19004371Free PMC article.
- Sodium channels as targets for volatile anesthetics.Herold KF, Hemmings HC Jr.Herold KF, et al.Front Pharmacol. 2012 Mar 30;3:50. doi: 10.3389/fphar.2012.00050. eCollection 2012.Front Pharmacol. 2012.PMID:22479247Free PMC article.
- Presynaptic inhibition of the release of multiple major central nervous system neurotransmitter types by the inhaled anaesthetic isoflurane.Westphalen RI, Desai KM, Hemmings HC Jr.Westphalen RI, et al.Br J Anaesth. 2013 Apr;110(4):592-9. doi: 10.1093/bja/aes448. Epub 2012 Dec 4.Br J Anaesth. 2013.PMID:23213036Free PMC article.
- Bidirectional modulation of isoflurane potency by intrathecal tetrodotoxin and veratridine in rats.Zhang Y, Guzinski M, Eger EI 2nd, Laster MJ, Sharma M, Harris RA, Hemmings HC Jr.Zhang Y, et al.Br J Pharmacol. 2010 Feb;159(4):872-8. doi: 10.1111/j.1476-5381.2009.00583.x. Epub 2010 Jan 25.Br J Pharmacol. 2010.PMID:20105175Free PMC article.
Publication types
MeSH terms
Substances
Related information
Grants and funding
LinkOut - more resources
Full Text Sources
Other Literature Sources
Miscellaneous