[Effect of potassium and calcium channel blockers on changes in the transepithelial potential and spike responses of electroreceptors of the ampullae of Lorenzini in the skate].

Action of TEA, 4-AP, Co2+, Cd2+, Cs+, EDTA and verapamile on sensory epithelium of Lorenzinian ampullae was studied in the Black Sea skate Raja clavata. Application of TEA to the basal face of epithelium in current-clamped ampulla caused oscillations of transepithelial potential and oscillatory spike discharges in response to excitatory stimulation. The oscillations were suppressed by Co2+, Cd2+ and EDTA. Application of Cs+ was followed by partial or complete suppression of spike response adaptation. TEA injection into the ampulla produced an increase in the spike frequency reaction and speeding of adaptation. Co2+, Cd2+ and verapamile inside the ampulla caused almost no changes. The contribution of various ionic channels to the function of the electroreceptor cell is discussed.