[Electrophysiologic study of the cholinergic receptor of the myocardial membrane].

A double sucrose gap voltage clamp technic has been used to study the extra-current induced by acetylcholine (Iach) on the myocardial membrane on frog atrial trabeculae. I) No desensitization of the Iach current is noted for repeated perfusions of Ach. II) The Iach current is suppressed by atropine. III) The reversal potential Each is more negative than the resting potential --20 mV less than or equal to Each less than or equal to OmV.IV) The relationship Iach/Holding potential for various [K+]o shows a) That Each behaved as a potassium electrode, b) an inward going rectification. These results indicate that the cholinergic receptor might be related with the gk1 channel.