Analysis of the effects of bromocriptine on blood pressure and sympathetic nerve function.

Bromocriptine, a dopamine receptor agonist, lowered arterial blood pressure and caused significant impairment of the cardioacceleration observed during the stimulation of the right postganglionic cardiac sympathetic nerve fibers in pentobarbital-anethetized dogs. Prior administration of pimozide antagonized the hypotensive and the inhibitory action of bromocriptine on cardiac sympathetic function. These results suggest that while presynaptic dopamine receptors seem to be involved in mediating the inhibitory action of bromocriptine on cardiac sympathetic function, the role of presynaptic as well as dopamine receptors located at other sites in mediating the hypotensive action of bromocriptine needs to be further investigated.