Influence of isobutylmethylxanthine on the direct current electroretinogram of albino rabbit eyes.

The direct current electroretinogram and the standing potential of the eye were recorded from both eyes of unilaterally vitrectomized albino rabbits. The effect of intraocular irrigation with the nonselective phosphodiesterase inhibitor isobutylmethylxanthine (IBMX) was compared with that of a balanced salt control solution. IBMX (0.5 mM) produced a reversible increase in the amplitudes of the a-wave (19%, p less than 0.02), b-wave (21%, p less than 0.001) and c-wave (12%, p less than 0.01) of the electroretinogram. A small elevation of the standing potential was found (0.4 +/- 0.2 mV), but this increase was not statistically significant (p greater than 0.05). The results indicate a primary and principal influence of IBMX on the photoreceptors.