[Amino acid neurotransmitter receptors of carp brain expressed in amphibian oocytes].

GABA receptor and inotropic glutamate receptors were expressed in amphibian oocytes and studied with the voltage-clamp technique and pharmacological method after injection of mRNA from carp (Carassius carassius) brains. It was found that about 90% of the response to GABA was mediated by GABAA receptor, but there was also about 10% of the response which was insensitive to bicuculline, a selective antagonist to GABAA receptor, baclofen, a selective agonist to GABAB receptor, had no effect on the injected oocytes. These observations suggest the existence of GABAC receptor. Subtypes of glutamate receptors, including NMDA subtype, KA/AMPA subtype and metabotropic glutamate receptors were also expressed and the dose-response relations were studied. Furthermore, we found that NMDA competitively suppressed the current response to KA, suggesting that NMDA probably was a weak antagonist of the KA/AMPA receptor.