Effects of retinal intrinsic dopamine on the in in vivo electroretinogram of rabbits
Kobayashi, A.; Shirao, Y.; Tagawa, S.; Katoh, K.; Tamura, T.
Nippon Ganka Gakkai Zasshi 100(2): 111-117
1996
ISSN/ISBN: 0029-0203 PMID: 8851149 Document Number: 468666
The effects of intravitreal injection of nomifensine, a potent dopamine uptake blocker, on the electroretinogram (ERG) were investigated in rabbit. Nomifensine enhanced the amplitude of the oscillatory potentials at 100 mu-M (intravitreal concentration) and 300 mu-M (p lt 0.05), but it attenuated the oscillatory potentials at 1,000 mu-M (p lt 0.01). Nomifensine attenuated the amplitude of the scotopic b-wave at 100 mu-M and 1,000 ELM (p lt 0.05), leaving the peak latency of the scotopic b-wave unaltered at all concentrations tested (30, 100, 300, 500 and 1,000 mu-M). Neither the amplitude nor the peak latency of the dark-adapted a- and b-waves elicited by bright stimuli was altered at any nomifensine concentration tested. 1 mu-M dopamine and 30 mu-M nomifensine together, each of which is insufficient to alter either of the scotopic b-wave or the oscillatory potentials when applied alone, reduced the scotopic b-wave and enhanced the oscillatory potentials. These results suggest that intrinsic dopamine release in the retina is large enough to alter the ERG.