Dopamine negatively modulates its own blood pressure increasing action.
To evaluate the mechanisms of the hypertensive action of dopamine and its dependence on its metabolic patterns we infused a borderline hypertensive dose of free dopamine into healthy subjects. The moderate rise in systolic and diastolic blood pressure with an expected considerable increase of plasma free dopamine concentrations was associated within 30 minutes with an increase in plasma free norepinephrine and huge increases in plasma 3-4-dihydroxyphenylacetic acid, homovanillic acid and dopamine sulfate, the latter mostly between 60 and 180 minutes of infusion when diastolic blood pressure decreased. The overall pre-, per- and postinfusion changes in systolic blood pressure were negatively correlated with corresponding changes of free dopamine and dopamine sulfate. Reproducible patterns of blood pressure responses to the dopamine infusion made possible a subdivision into those who were blood pressure responders (who generated dopamine sulfate with delay) and non responders (who generated dopamine sulfate immediately). The data suggests that the 4 micrograms/kg/min dopamine infusion rate raises blood pressure indirectly via norepinephrine. Free dopamine and dopamine sulfate (the velocity of generation of which may be an inherited trait) are probably negative modulators of this action.
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D004298:Dopamine / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D004341:Drug Evaluation; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D009638:Norepinephrine / Q000097:blood; D013997:Time Factors
D004298:Dopamine; D009638:Norepinephrine