Action of baclofen, GABA and antagonists on the membrane potential of cultured astrocytes of rat spinal cord

Autor: L. Hösli, Elisabeth Hösli, J. Rojas, H. Schramek, S. Redle
Rok vydání: 1990
Předmět:
Zdroj: Neuroscience Letters. 117:307-312
ISSN: 0304-3940
Popis: The action of γ-aminobutyric acid A (GABA A ) and B (GABA B )-agonists has been studied on the membrane potential of astrocytes in explant cultures of rat spinal cord by means of intracellular microelectrode recordings. The GABA B -agonists (−)-baclofen and CGP 27 492 (3-aminopropyl phosphonous acid; 10 −6 to 10 −4 M) caused a hyperpolarization of the majority of astrocytes studied. On approximately 25% of the cells, the compounds had no effect. The hyperpolarization by baclofen (10 −4 M) was reversibly antagonized by the GABA B -antagonist 5-hydroxysaclofen (10 −4 M). GABA and the GABA A -agonist muscimol (10 −4 and 10 −3 M) depolarized approximately two thirds of the glial cells tested, whereas the remaining third remained unaffected. The GABA A -antagonist bicuculline (10 −4 and 10 −3 M) only reduced the depolarization by GABA (10 −4 M) but did not completely block it. On half of the cells tested, the depolarization by GABA was not affected by bicuculline, suggesting that the glial GABA A -receptor is different from the neuronal GABA A -receptor. Our electrophysiological investigations together with recent autoradiographic binding studies strongly suggest the existence of GABA B -receptors on astrocytes whereas there is less evidence for GABA A -sites on these cells.
Databáze: OpenAIRE