Article date: 1991/5/13
PubMed ID: 1650936
Journal name: Neuroscience letters (ISSN: 0304-3940)
The influence of muscimol (a specific gamma-aminobutyric acid-A (GABAA) receptor agonist) on intracellular pH (pHi) was studied in cultured rat astrocytes by means of fluorescence spectrophotometry with BCECF as the H+ indicator. In an HCO3(-)-free medium, muscimol had little effect on pHi. In a solution containing 22 mM HCO3-, muscimol produced a reversible, concentration-dependent fall in pHi with a maximum of about 0.1-0.15 units. The muscimol-induced fall in pHi was antagonized by an increase in the external K+ concentration, which suggest that the acidosis is an immediate consequence of a net efflux of HCO3- through GABAA receptor channels rather than an indirect effect caused by a change in membrane potential. The present results raise the possibility that astrocytes may participate in the regulation of extracellular pH at GABAergic synapses and contribute to activity-induced pH changes in nervous tissue.
Author List: Kaila K, Panula P, Karhunen T, Heinonen E
Publication Types: Journal Article; Research Support, Non-U.S. Gov't
Substances mentioned in the article: Fluoresceins; Fluorescent Dyes; Receptors, GABA-A; Muscimol; 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein;
Mesh terms: Animals; Animals, Newborn; Astrocytes/drug effects; Cells, Cultured; Fluoresceins; Fluorescent Dyes; Hydrogen-Ion Concentration; Kinetics; Muscimol/pharmacology; Rats; Rats, Inbred Strains; Receptors, GABA-A/drug effects; Spectrometry, Fluorescence;