Quinpirole treatment increases renal sympathetic nerve activity and baroreflex gain in conscious rabbits: a spectral study.

Intravenous administration of 0.3 mg/kg of quinpirole to conscious rabbits that had been pretreated with domperidone caused a marked increase in blood pressure and renal sympathetic nerve activity with a peak at 5-10 min after injection (25% and 3-fold increase, respectively). Spectral analysis of the blood pressure-renal sympathetic nerve activity relationship in the 0.2-0.4 Hz domain showed that baroreflex gain was markedly increased at 5-10 min (4-fold) and at 20-25 min after injection (3.7-fold). These results show that administration of the dopamine D(2)/D(3) receptor agonist quinpirole causes profound and long-lasting changes in the central integration of the sympathetic baroreceptor-vasomotor reflex.