Sympathetic alterations after sodium restriction and short-term captopril administration.
OBJECTIVE
The purpose of this study was to examine the effects of short-term captopril therapy during sodium restriction on several markers of the sympathetic nervous system, including plasma norepinephrine, neuropeptide Y, beta-adrenergic receptors and cortisol.


BACKGROUND
Recent studies suggest that the therapeutic effects of converting enzyme inhibitors involve not only the renin-angiotensin and prostaglandin systems but also the sympathetic system.


METHODS
Twelve hypertensive and 20 normotensive men were studied after 2 5-day hospital stays during which they consumed a 10-mEq sodium diet and received captopril (25 mg twice daily) or placebo in a double-blind crossover study.


RESULTS
Captopril decreased neuropeptide Y (p < 0.05) and angiotensin II (p < 0.01) and increased isoproterenol-stimulated cyclic adenosine monophosphate (AMP) in lymphocytes (p < 0.03), plasma norepinephrine (p < 0.02), cortisol (p < 0.05) and renin (p < 0.001) in both hypertensive and normotensive subjects. Hypertensive subjects had an increased beta-adrenergic receptor density (p < 0.02) and a greater decrease in diastolic blood pressure compared with normotensive subjects (p < 0.02).


CONCLUSIONS
The results of this study suggest that the short-term therapeutic effects of captopril may involve concerted changes in key components of the sympathetic nervous system. These findings, such as decreased neuropeptide Y combined with increased norepinephrine and beta-adrenergic receptors, are compatible with the observation of increased cardiac output and decreased peripheral resistance after short-term angiotensin-converting enzyme inhibition.
Department of Medicine, University of California, San Diego Medical Center 92103-0804.
P J
PJ
Mills
J E
JE
Dimsdale
M G
MG
Ziegler
R L
RL
Hauger
R A
RA
Nelesen
M R
MR
Brown
D000704:Analysis of Variance; D002216:Captopril / Q000627:therapeutic use*; D004039:Diet, Sodium-Restricted; D004311:Double-Blind Method; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D006973:Hypertension / Q000097:blood / Q000188:drug therapy; D008214:Lymphocytes / Q000737:chemistry; D008297:Male; D009478:Neuropeptide Y / Q000097:blood; D009638:Norepinephrine / Q000097:blood; D011943:Receptors, Adrenergic, beta / Q000032:analysis; D012016:Reference Values; D012084:Renin-Angiotensin System / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects*; D013997:Time Factors
D009478:Neuropeptide Y; D011943:Receptors, Adrenergic, beta; D002216:Captopril; D006854:Hydrocortisone; D009638:Norepinephrine