Effect of steroids on γ-aminobutyrate-induced currents in cultured rat astrocytes

✍ Scribed by A. Chvátal; H. Kettenmann

• Publisher: Springer
• Year: 1991
• Tongue: English
• Weight: 417 KB
• Volume: 419
• Category: Article
• ISSN: 0031-6768
• DOI: 10.1007/bf00371105

✦ Synopsis

Cultured astrocytes from rat cortex respond to the inhibitory neurotransmitter y-aminobutyric acid (GABA) by the activation of C1-channels [Bormann J, Kettenmann H (1988) Proc Natl Acad Sci USA 85:9336-9340]. The glial response shares many pharmacological properties with those mediated by neuronal GABAA receptors, but differs in its sensitivity to inverse benzodiazepine agonists [Backus KH, Kettenmann H, Schachner M (1988) Glia 1:132-140]. To compare glial GABA receptors further with their neuronal counterparts, we analysed the effect of steroids, which have recently been shown to modulate neuronal GABAA-rece ptor-mediated responses, on GABA-induced currents in astrocytes. The agonist allotetrahydrodeoxycorticosterone (THDOC) at concentrations of 100 nM and 1 ~tM enhanced GABA-evoked (with 10 ~M GABA) currents up to 115~ and 162.4~ of controls respectively. The antagonist dehydroisoandrosterone 3-sulphate (DHEAS) at concentrations of 1 gM, 10 gM and 100 IxM depressed GABA-evoked (10txM) currents to 72070, 42.80/0 and 21.4% of controls respectively. The steroids were less effective at higher GABA concentrations. 100 gM DHEAS directly elicited a membrane current, while THDOC (1 gM) did not exert any direct response. This study demonstrates that steroids modulate GABA-evoked currents and thus may interfere with any of the functions of glial GABA receptors that are at present under discussion.