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 electroretinogram was examined in adult pigmented rabbits. Seven days after 6-hydroxydopamine treatment, which resulted in a depletion of the amine, partial retinal ischemia was induced by raising the intraocular pressure. As expected, moderate elevation of intraocular pressure produced increases in both a- and b-wave amplitudes. Amplitude hyperresponses were significantly reduced in dopamine-depleted retinas. These reductions were more prominent with relatively lower intensities. However, response delays were not shortened but lengthened by 6-hydroxydopamine pretreatment. Together, these results point to a selective role of dopamine in partial retinal ischemia induced by moderate elevation of intraocular pressure in rabbits.
Lafond
G
G
Department of Ophthalmology, Faculty of Medicine, University of Sherbrooke, Quebec, Canada.
Cao
W
W
Drumheller
A
A
Jolicoeur
F B
FB
Zaharia
M
M
Realbrunette
J
J
D000818:Animals; D004298:Dopamine / Q000172:deficiency*; D004596:Electroretinography; D007511:Ischemia / Q000503:physiopathology*; D016627:Oxidopamine / Q000494:pharmacology; D011817:Rabbits; D012160:Retina / Q000187:drug effects / Q000502:physiology*; D012171:Retinal Vessels / Q000503:physiopathology*
D016627:Oxidopamine; D004298:Dopamine