Intracellularly recorded early receptor potential of the vertebrate photoreceptors

Abstract

The early receptor potential was recorded intracellularly from single photoreceptors of Gekko gekko, Necturus maculosus and Siredon mexicanum. In the case of the gecko both the early and late receptor potentials have been recorded from both the inner and outer segments of the photoreceptor. The early receptor potential appears to be generated across the plasma membrane or a structure or structures electrically coupled to the plasma membrane. Moreover the membrane current associated with the ERP appears to be almost entirely capacitive. In the case of gecko the ERP decays with a time constant of 10.4 ± 0.4 msec. If this corresponds to the membrane time constant, the effective capacitance of the gecko photoreceptor is about 10 −9F.