D1 AGONIST CY208-243 ATTENUATES THE PATTERN ELECTRORETINOGRAM TO LOW SPATIAL-FREQUENCY STIMULI IN THE MONKEY

We investigated whether or not the D1 agonist, CY 208-243, affects the spatial tuning function of pattern electroretinogram (PERG), Two ligh tly anaesthetised monkeys were studied before and after CY 208-243 or placebo administration. The results show that the PERG response to 0.5 cycles/degree (c/d; coarse), but not to 2.3 c/d (medium) spatial freq uency stimuli disappears following systemic administration of this dru g. Since previous results show that D2 blockers attenuate the PERG onl y above 2.3 c/d, foremost the peak of the normal spatial frequency res ponse function, the current results suggest that dopamine itself, via D1 receptors, may be responsible for the low spatial frequency decline of normal spatial PERG tuning function. We infer that the synergistic activation of D1 and D2 receptors is needed to shape the spatially tu ned primate ERG. (C) 1998 Elsevier Science Ireland Ltd.