[Effects of retinal intrinsic dopamine on the in in vivo electroretinogram of rabbits].
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 microM (intravitreal concentration) and 300 microM (p < 0.05), but it attenuated the oscillatory potentials at 1,000 microM (p < 0.01). Nomifensine attenuated the amplitude of the scotopic b-wave at 100 microM and 1,000 microM (p < 0.05), leaving the peak latency of the scotopic b-wave unaltered at all concentrations tested (30, 100, 300, 500 and 1,000 microM). 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 microM dopamine and 30 microM 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.
Kobayashi
A
A
Department of Ophthalmology, Kanazawa University School of Medicine.
Shirao
Y
Y
Tagawa
S
S
Katoh
K
K
Tamura
T
T
D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D004596:Electroretinography; D009627:Nomifensine / Q000494:pharmacology; D011817:Rabbits; D012160:Retina / Q000187:drug effects / Q000378:metabolism*
D018765:Dopamine Uptake Inhibitors; D009627:Nomifensine; D004298:Dopamine