[Blocking action of calmidazolium and chlorpromazine on the potassium outward current which depends on intracellular calcium ions].

Effects of calmidazolium (R 24571) and chlorpromazine on the delayed potassium outward current in the somatic membrane were studied on nonidentified intracellularly perfused neurons of the snail Helix pomatia. Extracellular application of these substance evoked depression of the outward current. Inhibition of IK occurs at concentrations of calmodulin inhibitors 10(-9)-10(-8) mol/l. These agents inhibit primarily a component of the potassium current depending on the intracellular Ca2+ ions (IK(Ca in)). The inhibitory effect of these drugs can be explained by calmodulin-like structures of the receptor for intracellular calcium, providing modulation of IK(Ca in).