Implications for dopamine in central blood pressure regulation

The relationship between central nervous system blood pressure regulation and dopaminergic activity was investigated in anesthetized rats. The anterior hypothalamic/pre-optic region was unilaterally superfused push-pull cannula or unilaterally stimulated using a bipolar electrode. Following a stable, calcium dependent release of dopamine, the baroreceptor reflex loop was activated by an intra-arterial injection of blood. Dopamine release was enhanced considerably after the blood pressure increase and concomitant bradycardia. When in the ventral noradrenergic bundle was caused by a knife cut, the release of dopamine was significantly increased for at least 2 h. Stimulation of the anterior hypothalamic/pre-optic region elicited a transient decrease in pressure that was reduced or reversed by either the dopamine antagonist haloperidol or a higher frequency stimulation. In addition to a tonic mechanism controlling dopamine release, the data may indicate a functional for dopamine in central nervous system blood pressure regulation.