Electrooculographic and electroretinographic study in the chicken after dopamine and haloperidol

Abstract

The implication of dopamine in the modulation of the standing potential of the eye was tested in the chicken through an indirect electrooculographic method and direct current electroretinogram (ERG) recording after haloperidol, a mixed D1-D2 antagonist. The standing potential of the eye was reduced within 15 min after intravitreal injection of the antagonist (150 micrograms). This effect is rapidly reversed by an application of dopamine. The fast oscillation was preserved but the light peak was either strongly reduced or abolished. The dark trough showed an apparently normal time course. The intensity-voltage function was studied for the various ERG components. After haloperidol the b-wave and the c-wave were strongly reduced, whereas the a-wave was little affected. Together with previous data obtained with intraocular injections of dopamine, our data suggest the involvement of dopamine in the modulation of the standing potential. They also support the hypothesis that the light peak, which is generated by a photoreceptor-pigment epithelium interaction, is influenced by dopamine or by a related substance. The modulatory effect could also be due to a balance between several neurotransmitter systems.

EOG and ERG modifications induced in the chicken eye after blockade of catecholamine and 5-hydroxytryptamine biosynthesis

“…Preliminary data obtained with alpha methyl-para tyrosine (a tyrosine hydroxylase inhibitor) that only blocks DA synthesis are similar to those obtained with blockade of dopaminergic receptors through haloperidoh the SP is reduced and the light peak is depressed. [16] The comparison of the data obtained with these two biosynthesis inhibitors suggests that more than one neurotransmission system is involved in the modulation of the SP and the generation of the light peak.…”

Effects of direct intravitreal dopamine injections on the development of lid-suture induced myopia in rabbits

“…It is unclear how DA affects ocular growth. The mechanism of DA inhibition could lie in the DA modulation of RPE cells as was shown by the effects on RPErelated electrical signals [35,37] or molecular signals [34,35]. Wallman proposed a hypothesis that two signals may be involved in the local connection between the retina and sclera [34].…”

Electroretinographic effects of haloperidol on the mouse retina

“…A decrease in the b-wave was reported by Kupenova and Belcheva [3] in isolated frog eyecups and by Wioland and coworkers [11] in chicks with intravitreal injection, while an increase in the amplitude was described by Schneider and Zrenner [12] in isolated cat eyes and by Starr [2] in isolated rabbit eyes.…”

“…Actually, there are marked differences among different species in the distribution of dopaminergic neurons in the retina [16]. Wioland and associates [11] found that intraocular injection of haloperidol in chickens diminished the b-wave. Naarendorp and Sieving [10], however, reported that intravitreal injection of haloperidol increased PII in cats.…”

“…The dopaminergic neurons are located especially in the innermost row of the inner nuclear layer. To uncover the roles of dopamine in the retina, electrophysiologic methods have been used in animal experiments [2][3][4][5][6][7][8][9][10][11][12][13] and in clinical trials [7,14,15]. However, the physiologic results of these observations have varied because of high interspecies variability in numbers and distribution of dopaminergic neurons [16], differences in electrophysiologic methods used and the method of administration and doses of drugs.…”