Halothane suppression of spinal sensory neuronal responses to noxious peripheral stimuli is mediated, in part, by both GABAA and glycine receptor systems

Masanori Yamauchi, Hiroshi Sekiyama, Steven G. Shimada, J. G. Collins

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)

Abstract

Background: A major effect of general anesthesia is lack of response in the presence of a noxious stimulus. Anesthetic depression of spinal sensory neuronal responses to noxious stimuli is likely to contribute to that essential general anesthetic action. The authors tested the hypothesis that γ-aminobutyric acid receptor type A (GABAA) and strychnine-sensitive glycine receptor systems mediate halothane depression of spinal sensory neuronal responses to noxious stimuli. Methods: Extracellular activity of single spinal dorsal horn wide dynamic range (WDR) neurons was recorded in decerebrate, spinal cord transected rats. Neuronal responses to noxious (thermal and mechanical) and nonnoxious stimuli were examined in the drug-free state. Subsequently, cumulative doses (0.1-2.0 mg/kg) of bicuculline (GABAA antagonist) or strychnine (glycine antagonist) were administered intravenously in the absence or presence of 1 minimum alveolar concentration (MAC) of halothane. Results: Halothane, 1.1%, depressed the response of WDR neurons to both forms of noxious stimuli. Antagonists, by themselves, had no effect on noxiously evoked activity. However, bicuculline and strychnine (maximum cumulative dose, 2.0 mg/kg) partially but significantly reversed the halothane depression of noxiously evoked activity. Similar results were seen with most, but not all, forms of nonnoxiously evoked activity. In the absence of halothane, strychnine significantly increased neuronal responses to low threshold receptive field brushing. Conclusion: Halothane depression of spinal WDR neuronal responses to noxious and most nonnoxious stimuli is mediated, in part, by GABAA GABA, and strychnine-sensitive glycine systems. A spinal source of glycine tonically inhibits some forms of low threshold input to WDR neurons.

Original languageEnglish
Pages (from-to)412-417
Number of pages6
JournalAnesthesiology
Volume97
Issue number2
DOIs
Publication statusPublished - 2002 Aug 15
Externally publishedYes

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

Fingerprint Dive into the research topics of 'Halothane suppression of spinal sensory neuronal responses to noxious peripheral stimuli is mediated, in part, by both GABA<sub>A</sub> and glycine receptor systems'. Together they form a unique fingerprint.

Cite this