Evidence that a novel dopamine receptor agonist, RDS-127 [2-di-n-propylamino-4,7-dimethoxyindane] has some centrally mediated cardiovascular actions

The cardiovascular effects of RDS-127 [2-di-n-propylamino-4,7-dimethoxyindane] were examined in normotensive, anaesthetized rats. RDS-127 given i.v. (12.5-125 micrograms kg-1) produced dose-dependent bradycardia. The bradycardic effect was 20.5 times more potent when the drug was administered intracerebroventricularly (i.c.v.) than when given i.v. RDS-127 produced a slight, but significant hypotension. Haloperidol given i.c.v. or i.v. reversed these bradycardic and hypotensive actions, whereas phentolamine was ineffective. Methylatropine partially reduced the bradycardic effect. These results suggest that RDS-127 activates central DA receptors to produce hypotension and bradycardia in rats.