GABAA receptors inhibit acetylcholine release in cat pontine reticular formation

Implications for REM sleep regulation

Jacqueline Vazquez, Helen Baghdoyan

Research output: Contribution to journalArticle

56 Citations (Scopus)

Abstract

This study used in vivo microdialysis in cat (n = 12) to test the hypothesis that gamma aminobutyric acid A (GABAA) receptors in the pontine reticular formation (PRF) inhibit acetylcholine (ACh) release. Animals were anesthetized with halothane to hold arousal state constant. Six concentrations of the GABAA receptor antagonist bicuculline (0.03, 0.1, 0.3, 1, 3, and 10 mM) were delivered to a dialysis probe in the PRF, and endogenously released ACh was collected simultaneously. Bicuculline caused a concentration dependent increase in ACh release (maximal increase = 345%; EC50 = 1.3 mM; r2 = 0.997). Co-administration of the GABAA receptor agonist muscimol prevented the bicuculline-induced increase in ACh release. In a second series of experiments, the effects of bicuculline (0.1, 0.3, 1, and 3 mM) on ACh release were examined without the use of general anesthesia. States of wakefulness, rapid-eye-movement (REM) sleep, and non-REM sleep were identified polygraphically before and during dialysis delivery of bicuculline. Higher concentrations of bicuculline (1 and 3 mM) significantly increased ACh release during wakefulness (36%), completely suppressed non-REM sleep, and increased ACh release during REM sleep (143%). The finding that ACh release in the PRF is modulated by GABAA receptors is consistent with the interpretation that inhibition of GABAergic transmission in the PRF contributes to the generation of REM sleep, in part, by increasing pontine ACh release.

Original languageEnglish (US)
Pages (from-to)2198-2206
Number of pages9
JournalJournal of Neurophysiology
Volume92
Issue number4
DOIs
StatePublished - Oct 1 2004
Externally publishedYes

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GABA Receptors
REM Sleep
Acetylcholine
Sleep
Cats
Bicuculline
Wakefulness
Eye Movements
Dialysis
Pontine Tegmentum
Muscimol
Microdialysis
Halothane
Arousal
General Anesthesia

All Science Journal Classification (ASJC) codes

  • Physiology
  • Neuroscience(all)

Cite this

GABAA receptors inhibit acetylcholine release in cat pontine reticular formation : Implications for REM sleep regulation. / Vazquez, Jacqueline; Baghdoyan, Helen.

In: Journal of Neurophysiology, Vol. 92, No. 4, 01.10.2004, p. 2198-2206.

Research output: Contribution to journalArticle

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