Ion channel modulation as the basis for general anesthesia

(1) Modulation of the function of the GABA(A) and neuronal nicotinic acetyl choline receptor channels caused by general anesthetics and modulation of t he GABA(A) receptor-channel by halothane, enflurane, isoflurane, and n-octa nol was channel state-dependent. (3) Halothane modulation of the GABA(A) re ceptor was independent of subunits, but n-octanol modulation was subunit-de pendent. (4) Ethanol at 30-100 mu M was very potent in accelerating the des ensitization of currents induced by acetylcholine. (5) The ethanol modulati on was subunit: and state-dependent, occurring in the alpha 3 beta 4 combin ation but only weakly in the alpha 3 beta 2 combination. (6) In contrast, h alothane at 430 mu M (similar to 1 MAC) potently suppressed ACh-induced cur rents in the alpha 3 beta 2 subunit combination. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.