Evidence for a functional central dopaminergic insufficiency in the spontaneously hypertensive rat

Several neuroendocrine abnormalities reported in the spontaneously hypertensive rat (SHR) suggest that the function of the dopaminergic tuberoinfundibular tract is impaired in this strain. SHR were pretreated with the peripheral acting inhibitor of dopa decarboxylase, carbidopa, or vehicle. Intravenous injection of L-dopa, the precursor of dopamine, lowered blood pressure only in the carbidopa treated SHR suggesting a central dopamine action. Intracerebroventricular injection of dopamine in SHR lowered blood pressure towards normal. The data are in agreement with the hypothesis that SHR have a functional central dopaminergic insufficiency.