Evidence of decreased plasma substance p levels in human essential hypertension influence of prazosin treatment

Faulhaber H. D.; Rathsack R.; Rostock G.; Homuth V.; Pfeiffer D.; Naumann E.; Hartrodt W.; Goerne R. C.; Oehme P.

Patients with essential hypertension (n = 45) had significantly lower substance P plasma levels (13.6 .+-. 2.30 pg/ml) in comparison with a group of 24 normotensive subjects (45.4 .+-. 7.18 pg/ml) analyzed by radioimmunoassay. Prazosin treatment for 2 wk with 4.5 mg/day enhanced the substance P plasma level depending on its antihypertensive effect. Norepinephrine concentration in plasma was also elevated by prazosin. Dipeptidylpeptidase IV, dopamine-.beta.-hydroxylase and plasma renin activity were not changed significantly. Evidently, substance P participates in pathophysiological processes of human essential hypertension.