Investigative Ophthalmology & Visual Science, Vol 27, 1395-1403, Copyright © 1986 by Association for Research in Vision and Ophthalmology

ARTICLES AND REPORTS

The influence of phosphodiesterase inhibitors on ERG and optic nerve response of the cat

T Schneider and E Zrenner

Reversible changes in electroretinograms (ERG) and optic nerve responses (ONR), induced by various concentrations of four different types of phosphodiesterase (PDE)-inhibitors, were recorded from arterially perfused, isolated cat eyes. In the dark-adapted eye, the implicit time of the PIII-component of the ERG, isolated by temporary hypoxia, showed a dose-dependent increase after the injection of PDE- inhibitors into the ophthalmociliary artery. The PIII-amplitude increased in response to small doses of PDE-inhibitors, whereas higher doses led to an amplitude decrease. Rod b-wave amplitude and implicit time showed similar alterations. An amplitude increase could not be observed in the rod ONR. In the light-adapted eye, 440 nm and 555 nm cones were functionally separated by means of chromatic adaptation. Their ERG and ONR implicit times were prolonged under PDE-inhibition. The amplitude behaviour of both types of cones showed a different concentration dependency. Certain concentrations of PDE-inhibitors depressed the short-wavelength sensitive cone, while, at the same time, sensitizing the long-wavelength sensitive cone. The amplitude increase of the L-cone b-wave was accompanied by a response increase of tonic ganglion cells in the ONR.