Effects of low doses of forskolin on the c-wave of the direct current electroretinogram and on the standing potential of the eye

A marked effect of prostaglandins on the b- and c-waves of the direct current electroretinogram was recently reported by our laboratory. The increased b- and c-wave amplitudes in response to prostaglandins may be mediated by cyclic nucleotides acting on fluid and ion transport across the retinal pigment epithelium (RPE). Forskolin is known to increase cyclic adenosine monophosphate in a number of tissues, among them the RPE. To study possible effects of forskolin on the ERG vitrectomy was performed on rabbit eyes, followed by intraocular irrigation with a forskolin solution (10g/ml PHS). Forskolin produced reversible ERG changes with increase in a- (24%, p < 0.001), b- (25%, p < 0.001) and c-wave (53%, p < 0.001) amplitudes and elevation (about 1.0–1.5mV, p < 0.01) of the standing potential of the eye. The increase in c-wave amplitude was significantly greater than that of the a- (p < 0.05) and b- (p < 0.01) wave amplitudes, which seems to imply a primary or at least major effect on the RPE.