Activation by systemic GABA of vagal efferent transmission in the rat: correlation to its acid secretagogue action.
Stimulatory effects of systemically administered gamma-aminobutyric acid (GABA) on gastric acid secretion and vagal efferent activity were studied in anesthetized rats. Intravenous injection of GABA (400 mg/kg) significantly increased gastric acid secretion. The secretagogue effect of GABA on the gastric acid secretion was partially attenuated by vagotomy by approximately 60%. Atropine (1 mg/kg, s.c.) completely abolished the stimulatory effect of GABA on the acid output. GABA, at secretagogue doses, enhanced the firing rate of vagal efferent activity. These results suggest that the secretagogue action of intravenously injected GABA is primarily mediated by muscarinic mechanisms and that the stimulation of the central vagal efferent pathway might trigger the excitatory action of systemic GABA.
Yamasaki
K
K
Department of Pharmacology, Tokushima Bunri University, Japan.
Goto
Y
Y
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005744:Gastric Acid / Q000378:metabolism*; D008297:Male; D009476:Neurons, Efferent / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D009435:Synaptic Transmission / Q000187:drug effects; D013997:Time Factors; D014628:Vagotomy; D014630:Vagus Nerve / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology / Q000502:physiology*
D005680:gamma-Aminobutyric Acid; D001285:Atropine