Volatile general anaesthetic actions on recombinant nACh(α7), 5-HT₃ and chimeric nACh(α7)-5-HT₃ receptors expressed in Xenopus oocytes

The effect of halothane and isoflurane was studied on the function of recombinant neurotransmitter receptors expressed in Xenopus oocytes. Both anaesthetics inhibited nicotinic acetylcholine type α7 (nACh(α7)) receptor-mediated responses, potentiated 5-hydroxytryptamine type 3 (5-HT₃) receptor-mediated responses at low agonist concentrations, and inhibited the function of a chimeric receptor (with the N-terminal domain from the nACh(α7) receptor and the transmembrane and C-terminal domains from the 5-HT₃ receptor) in a manner similar to that of the nACh(α7) receptor. Since the N-terminal domain of the chimeric receptor was from the nACh(α7) receptor, the observations suggest that the inhibition involves the N-terminal domain of the receptor.