The heterogeneity of dopamine involvement in essential hypertension

Compared to control subjects, patients with essential hypertension (EH) had a decreased urinary DA:NE ratio and an overall increase in the total (free + sulfated) plasma sum of NE, E and DA. With age-matching, this elevation was found to be due to augmented levels of DA sulfate. When subdivided into borderline (labile) and stable EH groups, only the borderline EH patients had heightened plasma DA sulfate levels, enhanced urinary homovanillic acid excretion and tended to have plasma NE and PRA increases. Patients with stable EH had a hyporesponsive urinary DA and Na+ excretion as well as reduced PRA levels at the height of furosemide-induced natriuresis. These data are compatible with a hyperdopaminergic component of the hyperadrenergic state, more or less affecting patients with borderline EH in contrast to the hypodopaminergic features of subjects evolving into stable EH in whom the neurogenic component subsides. In both EH subgroups, urinary DA lagged behind NE excretion. Dopaminergic tone may indirectly affect endogenous DA-modulated renal, adrenal and vascular synaptic processes as well as their responses to exogenous Angiotensin II and DA, respectively.