[Effect of potassium ions on the electrical activity of ampullae of Lorenzini in the skate].

Effect of different concentration of externally applied K+ on the resting and evoked discharge of the isolated Lorenzini ampullae was studied in skates. It was shown that low K+ or K+-free solutions caused a decrease in the frequency of the afferent discharge. An increase in K+ concentration (6-10 mM) produced a reversible increase in the resting activity, with no effect on the receptor thresholds to electrical stimulation. When synaptic transmission was abolished by Mg+2 (30-40 mM) an increase in K+ concentration induced no activity in the afferent nerve discharge. However if L-glutamate was added to the Mg+2-containing solution, it partially restored the activity and addition of K+ caused an additional increase in the existing activity.