Respiratory and Electrical Responses to Light Stimulation in the Retina of the Frog

Isolated retinas from frogs' eyes were preserved in a circulating medium; transretinal electrical potential and ultraviolet absorbancy were monitored. In response to visible stimulation, changes in absorbancy were observed which correlate with the c-wave of the electroretinogram. They are tentatively identified as cyclic oxidations of pyridine nucleotides reflecting the energy expenditure associated with evoked neuronal activity.