Article date: 1990/9/18
PubMed ID: 2094820
Journal name: Neuroscience letters (ISSN: 0304-3940)
The action of gamma-aminobutyric acid A (GABAA) and B (GABAB)-agonists has been studied on the membrane potential of astrocytes in explant cultures of rat spinal cord by means of intracellular microelectrode recordings. The GABAB-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 GABAB-antagonist 5-hydroxysaclofen (10(-4) M). GABA and the GABAA-agonist muscimol (10(-4) and 10(-3) M) depolarized approximately two thirds of the glial cells tested, whereas the remaining third remained unaffected. The GABAA-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 GABAA-receptor is different from the neuronal GABAA-receptor. Our electrophysiological investigations together with recent autoradiographic binding studies strongly suggest the existence of GABAB-receptors on astrocytes whereas there is less evidence for GABAA-sites on these cells.
Author List: Hösli L, Hösli E, Redle S, Rojas J, Schramek H
Publication Types: Journal Article
Substances mentioned in the article: GABA Antagonists; Organophosphorus Compounds; 3-aminopropylphosphinic acid; 5-hydroxysaclofen; Muscimol; gamma-Aminobutyric Acid; Baclofen; Bicuculline;
Mesh terms: Animals; Astrocytes/drug effects; Autoradiography; Baclofen/analogs & derivatives; Bicuculline/pharmacology; Electrophysiology; Female; GABA Antagonists; Membrane Potentials/drug effects; Microelectrodes; Muscimol/pharmacology; Organophosphorus Compounds/pharmacology; Pregnancy; Rats; Spinal Cord/cytology; gamma-Aminobutyric Acid/pharmacology;