Dopaminergic inhibition of cardiac sympathetic nerve function by pergolide

The effect of pergolide, a dopaminergic ergoline, on cardiac sympathetic neurotransmission was examined in pentobarbital-anesthetized dogs. Positive chronotropic responses to right postganglionic cardioaccelerator nerve stimulation were significantly reduced following infusion of pergolide, 1.25 microgram/kg per min for 10 min, whereas positive chronotropic responses to exogenous norepinephrine were unchanged. Pretreatment with sulpiride but not with yohimbine completely antagonized the inhibitory effect of pergolide. These results demonstrate that pergolide inhibits sympathetic neurotransmission to the heart by a specific activation of presynaptic dopamine receptors.