Study of the receptor mechanisms of the electroreceptors of ampullae of Lorenzini in the skate

: Responses of the sensory epithelium of the electrically insulated Lorenzinian ampullae in the Black Sea skates (Raja clavata) as well as their spike frequency reactions to electrical stimulation were studied under the current-clamp conditions. The preparations have the input resistance of 200-800 k omega, the transepithelial resting potential of 0 divided by -2 mV and ordinary impulse activity in afferent fibres. Electroreceptor thresholds were of 2-10 microV (current approximately 10-11 A). With adequate parameters of stimulation (current up to 1 nA, voltage drop across the epithelium to +/-500 microV) the current-voltage relation of the epithelium was linear without any signs of both spike and oscillatory activity of the receptor cells. With negative currents more than 1-10 nA there appeared a regenerative spike in the epithelium. The spike was accompanied by abnormal impulse in an afferent fibre.