Serotonin elevates the c-wave of the electroretinogram of the rabbit eye by increasing the transepithelial potential

Abstract

The influence of serotonin (5-hydroxytryptamine, 5-HT) and serotonin analogues on the direct current electroretinogram (d.c. ERG) and the standing potential of the albino rabbit eye (SP) was studied. After unilateral vitrectomy, corneal recordings were obtained during simultaneous intravitreal perfusion with a control solution alternating with 5-HT at concentrations of 25, 120 and 200 microM. The c-wave increased at 25 and 120 microM when changing from control solution to test solution (P < 0.05) but did not decrease significantly when changing back to control solution (P > 0.05). The c-wave was reversibly elevated at 200 microM (PHS-5-HT, P < 0.01; 5-HT-PHS, P < 0.05). To analyse further the influence on the c-wave, in vivo intraretinal microelectrode recordings were obtained during intravitreal perfusion with 5-HT. The transepithelial potential (TEP) increased (P < 0.01), while the slow PIII was not significantly affected (P > 0.05). The serotonin receptor agonists 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane, 5-methoxytryptamine, alpha-methyl-5-hydroxytryptamine and 2-methyl-5-hydroxytryptamine, caused a significant reversible elevation of the c-wave, whereas 5-carboxyamidotryptamine did not. Tropisetron did not block the serotonin effect and LY53857 had an effect of its own on the c-wave. The results seem to indicate that the influence of serotonin on the c-wave is mainly due to an effect on the retinal pigment epithelium (RPE) and that more than one type of serotonin receptor may be involved.

Interaction between the serotoninergic and GABAergic systems in frog retina as revealed by electroretinogram

“…It appears that endogenous serotonin has inhibitory role on the b-wave generating mechanisms in pigeon retina, but excitatory role on the same mechanisms in rabbit retina. It has been found that application of exogenous serotonin increases the amplitude of the b-wave in cat (Skrandies and Wässle 1988) and rabbit (Bragadottir et al 1997) retina, which supports the suggestion that serotoninergic system has excitatory role on the b-wave generating mechanism in mammalian retina. Our finding that serotonin increas-es the amplitude of the b-wave in frog retina indicates that serotoninergic system has similar role in the amphibian retina as well.…”

Erythropoietin Gene Therapy Delays Retinal Degeneration Resulting from Oxidative Stress in the Retinal Pigment Epithelium

“…As these potentials can be related to specific cellular events, they provide information about RPE function and how that may be altered by disease or experimental manipulation [68]. In our study, we found significant preservation of c-wave ERG, and that could be correlated with strong RPE junctional integrity and healthy RPE [69,70]. Previously, using this model, we have seen that supplementation of daily zeaxanthin improved c-wave response compared to untreated mice [29].…”