Histochemical demonstration of cyclic guanosine 3',5'-monophosphate phosphodiesterase activity in retinal photoreceptor outer segments.

A technique for the histochemical demonstration of cyclic guanosine monophosphate phosphodiesterase in retina is described. Enzyme activity was identified on photoreceptor outer segment lamellae, a finding in agreement with previous biochemical data on isolated outer segment preparations. The distribution of phosphodiesterase activity for cyclic guanosine monophosphate was similar to that found previously in rod outer segments for cyclic adenosine monophosphate, suggesting that the same enzyme may hydrolyze both nucleotides.