[Zinc modulation of GABA receptors expressed in Xenopus oocytes injected with carp brain poly(A)+ RNA]

Two types of GABA receptors, GABAA receptors (approximately 85%) and GABAC-like receptors (approximately 15%), were expressed in Xenopus oocytes after injection of Poly(A)+ RNA with carp (Carassius carassius) brain. Using voltage-clamp technique and pharmacological methods, the effects of zinc on the two receptors were studied. It was found that zinc modulation of both GABAA and GABAC-like receptors by zinc was inhibitory and reversible with the former being stronger than the latter as indicated by a value of IC50 of 48.4 +/- 10.1 mumol/L against 255.6 +/- 21.5 mumol/L.