Effects of diuretics on GABA-gated chloride current in frog isolated sensory neurones.
1. Effects of three diuretics (furosemide, amiloride and alpha-human atrial natriuretic polypeptide (alpha-hANP] on GABA-activated chloride current (ICl) were investigated in frog isolated sensory neurones, following suppression of Na+, K+ and Ca2+ currents, by use of a 'concentration-clamp' technique. 2. Furosemide inhibited the GABA-activated ICl in a non-competitive manner and facilitated the inactivation phase, while amiloride inhibited the GABA response in a competitive manner, both inhibitions being concentration-dependent. Alpha-hANP had no effects on the GABA-induced ICl. 3. The reversal potential of GABA-activated ICl (EGABA) was not shifted in the presence of amiloride or furosemide. 4. The results suggest that amiloride may act at the GABA binding site while furosemide may act on the GABA-gated chloride channel.
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology; D001665:Binding Sites / Q000187:drug effects; D001667:Binding, Competitive; D002712:Chlorides / Q000378:metabolism*; D004232:Diuretics / Q000494:pharmacology*; D004553:Electric Conductivity / Q000187:drug effects; D005665:Furosemide / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects*; D009475:Neurons, Afferent / Q000187:drug effects*; D011898:Ranidae; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D002712:Chlorides; D004232:Diuretics; D007473:Ion Channels; D005680:gamma-Aminobutyric Acid; D000584:Amiloride; D005665:Furosemide; D009320:Atrial Natriuretic Factor