title: Angiotensin II mediates hyperadrenergic activity evoked by sodium restriction in essential hypertension.
abstract: We examined the possible involvement of angiotensin II in the modulation of circulating norepinephrine produced by acute sodium restriction in essential hypertensive patients (n = 18). Sodium restriction potentiated plasma level of norepinephrine in parallel with an increased plasma renin activity (r = 0.81, F = 31.2, p less than 0.05 given by the percent changes). An intravenous infusion of sarcosine-1, isoleucine-8 angiotensin II produced a significant fall in mean arterial pressure (-6 +/- 2 mmHg, p less than 0.05) in patients on sodium restriction but not before sodium restriction, while the infusion of the antagonist produced a greater decrease (p less than 0.05) in plasma norepinephrine with sodium restriction (-158 +/- 23 pg/ml, p less than 0.05) when compared to that obtained before sodium restriction (-91 +/- 11 pg/ml, p less than 0.05). A single oral administration of an angiotensin I converting enzyme inhibitor, captopril caused a greater fall (p less than 0.01) in mean arterial pressure after sodium restriction (-32 +/- 3 mmHg, p less than 0.05) compared to that given before (-21 +/- 3 mmHg, p less than 0.05). However, sodium restriction did not affect the magnitude of reflex increase in plasma norepinephrine to hypotension evoked by captopril (from +88 +/- 16 pg/ml to +87 +/- 17 pg/ml; p greater than 0.05). It can be interpreted that acute sodium depletion results in a substantial contribution of angiotensin II to the expression of hyperadrenergic activity.
authors.affiliation: Department of Medicine, Wakayama Medical College, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Mohara
authors.forename: Y
authors.initials: Y
authors.lastname: Masuyama
mesh_terms: D000311:Adrenal Glands / Q000187:drug effects*; D000328:Adult; D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D002216:Captopril / Q000494:pharmacology; D004039:Diet, Sodium-Restricted; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D007022:Hypotension / Q000139:chemically induced; D009638:Norepinephrine / Q000097:blood; D012083:Renin / Q000097:blood
chemical_list: D000804:Angiotensin II; D000450:Aldosterone; C009210:sarleucin; D002216:Captopril; D012083:Renin; D009638:Norepinephrine