Role of chloride in angiotensin II-induced salt-sensitive hypertension.
The present study investigated the effect of the anion accompanying sodium on the development of angiotensin II-induced hypertension in rats and the role of the sympathetic nervous system and extracellular fluid volume in its mechanism. Hypertension was induced by intraperitoneal infusion of angiotensin II (125 ng/min) for 12 days via miniosmotic pump. High dietary intake of sodium chloride significantly augmented the angiotensin II-induced hypertension (mean blood pressure on day 13, 165 +/- 6 versus 142 +/- 6 mm Hg, p less than 0.05), but equimolar sodium loading provided as sodium citrate failed to enhance angiotensin II hypertension (140 +/- 6 mm Hg). Plasma norepinephrine concentration in the conscious, resting state increased with sodium chloride loading in angiotensin II-infused rats (594 +/- 42 versus 312 +/- 37 pg/ml, p less than 0.01), but it remained unchanged with sodium citrate loading (324 +/- 23 pg/ml). Correspondingly, maximum response to hexamethonium bromide, a ganglion blocker, was greater in sodium chloride-loaded angiotensin II rats (77.7 +/- 4.6 mm Hg) than that in angiotensin II (59.7 +/- 5.1 mm Hg) or in sodium citrate-loaded angiotensin II (57.7 +/- 4.2 mm Hg) rats. Moreover, extracellular fluid volume, measured as Na2(35)SO4 space, increased in sodium chloride-loaded angiotensin II rats (427 +/- 18 ml/kg body wt) as compared with that in angiotensin II rats (375 +/- 15 ml/kg body wt) but not when compared with volume in sodium citrate-loaded angiotensin II (389 +/- 7 ml/kg body wt) rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Sato
Y
Y
Fourth Department of Internal Medicine, School of Medicine University of Tokyo, Japan.
Ogata
E
E
Fujita
T
T
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002712:Chlorides / Q000494:pharmacology*; D002951:Citrates / Q000494:pharmacology; D019343:Citric Acid; D005110:Extracellular Space / Q000187:drug effects; D006973:Hypertension / Q000139:chemically induced*; D007668:Kidney / Q000294:innervation; D008297:Male; D009638:Norepinephrine / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains; D012965:Sodium Chloride / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000502:physiology
D002712:Chlorides; D002951:Citrates; D000804:Angiotensin II; D019343:Citric Acid; D012965:Sodium Chloride; D009638:Norepinephrine