SELECTIVE EFFECTS OF RETINAL DOPAMINE DEPLETION ON PARTIAL ISCHEMIA-INDUCED ELECTRORETINOGRAPHIC HYPERRESPONSES IN RABBITS

The interaction of retinal dopamine depletion and partial ischemia on the a- and b-wave amplitudes and implicit times of the electroretinogr am was examined in adult pigmented rabbits. Seven days after 6-hydroxy dopamine treatment, which resulted in a depletion of the amine, partia l retinal ischemia was induced by raising the intraocular pressure. As expected, moderate elevation of intraocular pressure produced increas es in both a- and b-wave amplitudes. Amplitude hyperresponses were sig nificantly reduced in dopamine-depleted retinas. These reductions were more prominent with relatively lower intensities. However, response d elays were not shortened but lengthened by 6-hydroxydopamine pretreatm ent. Together, these results point to a selective role of dopamine in partial retinal ischemia induced by moderate elevation of intraocular pressure in rabbits.