2822450

Modulation of calcium uptake and D-aspartate release by GABAB receptors in cultured cerebellar granule cells.

Article date: 1987/9/23

PubMed ID: 2822450

Journal name: European journal of pharmacology (ISSN: 0014-2999)

ABSTRACT

(-)Baclofen, a GABAB receptor agonist, and GABA attenuated by 60% the high K+-evoked 45Ca2+ uptake into cultured cerebellar granule cells with an EC50 of 110 +/- 18 nM and 2.4 +/- 0.2 microM, respectively. The attenuation by baclofen of 45Ca2+ uptake was stereospecific and the effect of GABA was unaffected by bicuculline. Moreover, muscimol, a GABAA receptor agonist did not affect the K+-evoked 45Ca2+ uptake. (-)Baclofen and GABA also decreased the K+-evoked and calcium-dependent release of preloaded [3H]D-aspartate from granule cells; however, their potency and efficacy appeared to be less than those for inhibiting the 45Ca2+ uptake. (+)Baclofen and muscimol failed to change this K+-evoked release. The release of [3H]D-aspartate induced by the calcium ionophore A23187 was unaffected by (-)-baclofen. The K+-evoked release of [3H]D-aspartate was effectively inhibited by nimodipine, a voltage sensitive calcium channel blocker. The results suggest that GABAB receptor in cultured cerebellar granule cells plays a crucial role in modulating the uptake of calcium and release of the excitatory transmitter. Moreover, these two effects mediated by GABAB receptor activation may be casually related.

This document is available from: http://directlinks.cc/files/muscimol/2822450.pdf

Author List: Zhu X Z, Chuang D M

Publication Types: Journal Article

Substances mentioned in the article: Calcium Radioisotopes; Receptors, GABA-A; Muscimol; Aspartic Acid; Calcimycin; gamma-Aminobutyric Acid; Nimodipine; Baclofen; Calcium;

Mesh terms: Animals; Aspartic Acid/metabolism; Baclofen/pharmacology; Calcimycin/pharmacology; Calcium/metabolism; Calcium Radioisotopes; Cells, Cultured; Cerebellum/metabolism; Muscimol/pharmacology; Nimodipine/pharmacology; Rats; Receptors, GABA-A/metabolism; gamma-Aminobutyric Acid/pharmacology;

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