[Demonstration of subcomponents of PIII in the ERG of isolated rabbit retina using sodium asparaginate].

Experiments on the sum potential to dark flashes after eliminating the positive components by low temperature (25 degrees C) and low content of plasma (10% instead of 50%) in the perfusion fluid have shown that the cornea-negative component PIII is extensively reduced by application of 10 mM sodium aspartate. The existence of an aspartate sensitive PIII-subcomponent, which was first discovered by intraretinal records, is not in agreement with the opinion that the whole PIII represents receptor activity. Fast and slow PIII-subcomponents are also discernible in the cornea-negative PIII - recorded with cross-electrodes - by their time course without and with adding sodium aspartate. The fast subcomponents are demonstrable in a rough approximation by condenser-coupling the amplifier (t = 0.3 sec). Changing the temperature from 22 degrees C to 27 degrees C the temperature quotient amounts to 1,3 for the fast subcomponents, and to 2.1 for the whole PIII including the slow subcomponents.