1936787

gamma-Aminobutyric acid localization and function as modulator of cholinergic neurotransmission in rat antral mucosal/submucosal fragments.

Article date: 1991/11/1

PubMed ID: 1936787

Journal name: Gastroenterology (ISSN: 0016-5085)

ABSTRACT

gamma-Aminobutyric acid, a neurotransmitter in the central nervous system, has been shown to be present in and synthesized and secreted by rodent and feline myenteric plexus neurons. The aims of the present studies were to measure gamma-aminobutyric acid concentrations and synthesis and to establish cellular localization and uptake of gamma-aminobutyric acid by immunocytochemistry and autoradiography, respectively, within mucosal and submucosal tissues of the rat antrum. Direct demonstration of [3H]gamma-aminobutyric acid release and the effects of exogenous gamma-aminobutyric acid and muscimol, a GABA alpha agonist, on [3H]acetylcholine release from antral mucosal/submucosal fragments were examined in perifusion experiments. gamma-Aminobutyric acid content and synthesis, as reflected by glutamic acid decarboxylase activity, were present within antral mucosa at levels two to three times that of the body and muscular layers of both the gastric body and antrum. gamma-Aminobutyric acid was identified immunocytochemically, principally in mucosal epithelial cells of the antrum. Exogenous gamma-aminobutyric acid and muscimol were capable of stimulating acetylcholine release through a GABA alpha receptor-mediated mechanism that was abolished by tetrodotoxin. These results indicate that gamma-aminobutyric acid is present in and taken up by epithelial cells of the gastric antrum and that gamma-aminobutyric acid is capable of being synthesized by antral mucosal/submucosal tissues. Furthermore, these studies suggest that a peripheral gamma-aminobutyric acid mechanism that may modulate cholinergic neurotransmission and endocrine cell function exists within the antrum.

This document is available from: http://directlinks.cc/files/muscimol/1936787.pdf

Author List: Harty R F, Boharski M G, Bochna G S, Carr T A, Eagan P E, Rings M, Lassiter D C, Pour M P, Schafer D F, Markin R S

Publication Types: Journal Article; Research Support, U.S. Gov't, P.H.S.

Substances mentioned in the article: Muscimol; gamma-Aminobutyric Acid; Glutamate Decarboxylase; Acetylcholine;

Mesh terms: Acetylcholine/metabolism; Animals; Autoradiography; Digestive System/chemistry; Epithelial Cells; Epithelium/chemistry; Gastric Mucosa/chemistry; Glutamate Decarboxylase/metabolism; Immunohistochemistry; In Vitro Techniques; Intestinal Mucosa/chemistry; Male; Muscimol/pharmacology; Pyloric Antrum/chemistry; Rats; Rats, Inbred Strains; gamma-Aminobutyric Acid/analysis;

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