Differentiation of noradrenergic and dopaminergic neurons in the cardiovascular system.

Dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and norepinephrine (NE) are present in the rat cardiovascular system. All of the catechols can be partially depleted by administering 6-hydroxydopamine (6-HODA). When animals are pretreated with desipramine before 6-HODA, there is a selective partial depletion of DA and DOPAC. NE can be partially depleted with minimal effects on DA and DOPAC by administering N-(2-chloroethyl)N-ethyl-2-bromobenzylamine (DSP-4). These results are consistent with the hypothesis that independent dopaminergic and noradrenergic elements are present in the rat cardiovascular system and that DA is not solely a precursor for NE. NE, DA and DOPAC were assayed in human vessels and the pattern of distribution of the catechols is consistent with the results reported for animals.