Stimulation of endogenous cyclic AMP levels in ciliary body by SK&F 82526, a novel dopamine receptor agonist.

The effect of dopamine and SK&F 82526 on cyclic AMP metabolism in ocular tissues has been examined. The in vitro incubation of human and bovine ciliary body with these agonists produced a dose-dependent increase in endogenous levels of cyclic AMP. This stimulation was blocked by the selective DA1 receptor antagonist SK&F 83566, but not by the beta-receptor antagonist propranolol. The response to SK&F 82526 was stereoselective, with SK&F R-82526 being approximately 100 times more potent than SK&F S-82526 in this preparation. This stimulation of ciliary body cyclic AMP content was not observed in the rabbit or cat, nor was it seen in human, bovine or rabbit iris tissue. These data suggest that adenylate cyclase linked dopamine receptors are present in both human and bovine ciliary body.