Captopril attenuates reflex adrenergic response in essential hypertension.
An attenuation of adrenergic activity during the inhibition of endogenous angiotensin II formation was evaluated by determining plasma norepinephrine concentration after a single oral administration of captopril compared to that after nifedipine in essential hypertension. Captopril produced a fall in mean arterial pressure (-24 +/- 2 mmHg, p less than 0.01) which magnitude was the same as that gained by nifedipine (-22 +/- 3 mmHg, p less than 0.01). Reflex tachycardia due to hypotension was produced (+13 +/- 1 beats/min, p less than 0.01) after nifedipine but not after captopril (-1 +/- 2 beats/min, p greater than 0.05). Although the enhancement of plasma renin activity induced by captopril (+1.54 +/- 0.56 ng/ml/hr, p less than 0.05) was similar (p greater than 0.05) to that by nifedipine (+1.44 +/- 0.47 ng/ml/hr, p less than 0.05), plasma norepinephrine concentration increased less (p less than 0.01) after captopril (+100 +/- 23 ng/ml, p less than 0.05) than after nifedipine (+283 +/- 51 ng/ml, p less than 0.05). Thus, the diminished adrenergic activity is a likely candidate for the abolished reflex tachycardia after the inhibition of angiotensin I converting enzyme activity by captopril in essential hypertension.
Mohara
O
O
Department of Medicine, Wakayama Medical College, Japan.
Masuyama
Y
Y
D000284:Administration, Oral; D000328:Adult; D000450:Aldosterone / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D002216:Captopril / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D009543:Nifedipine / Q000494:pharmacology; D009638:Norepinephrine / Q000097:blood*; D012018:Reflex / Q000187:drug effects*; D012083:Renin / Q000097:blood; D013564:Sympathetic Nervous System / Q000502:physiology*
D000450:Aldosterone; D002216:Captopril; D012083:Renin; D009543:Nifedipine; D009638:Norepinephrine