Effect of dietary NaCl on norepinephrine turnover in the Dahl rat.
To evaluate neural mechanisms in salt-sensitive hypertension, norepinephrine turnover rates were measured in peripheral tissues and selected brain areas of Dahl salt-sensitive and salt-resistant rats receiving either 1% or 7% NaCl diets for 5 weeks. Norepinephrine turnover was determined by measuring tissue norepinephrine in untreated animals or in separate groups killed 2, 4, 6, and 10 hours after alpha-methyl-tyrosine. Plasma volume (radiolabeled albumin) was also measured. Arterial pressure of Dahl S rats receiving 7% NaCl (167 +/- 4 mm Hg) was higher (p less than 0.001) than that of Dahl S rats receiving 1% NaCl (141 +/- 3mm Hg), which was higher (p less than 0.001) than that of Dahl R rats receiving both NaCl intakes. Norepinephrine turnover was increased (p less than 0.01) by 7% NaCl in both heart and brown adipose tissue in Dahl S rats, whereas norepinephrine turnover in Dahl R rats was decreased (p less than 0.01) by the 7% NaCl intake in the heart and kidney. On the high NaCl intake, norepinephrine turnover in heart and adipose tissue was lower (p less than 0.05) in Dahl R rats than in Dahl S rats. In brain stem tissue, with the 1% NaCl diet, norepinephrine turnover was higher (p less than 0.001) in Dahl S rats than in Dahl R rats, and norepinephrine turnover was inhibited (p less than 0.001) by the high NaCl intake in Dahl S rats but not in Dahl R rats. In posterior hypothalamus, norepinephrine turnover was inhibited (p less than 0.01) by the high NaCl intake in Dahl R rats but not in Dahl S rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Kotchen
T A
TA
Department of Medicine, West Virginia University School of Medicine, Morgantown 26506.
Blehschmidt
N G
NG
Reddy
S R
SR
D002001:Adipose Tissue, Brown / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure; D001933:Brain Stem / Q000378:metabolism; D004032:Diet; D006973:Hypertension / Q000503:physiopathology; D007031:Hypothalamus / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D011922:Rats, Mutant Strains / Q000378:metabolism*; D012965:Sodium Chloride / Q000008:administration & dosage*
D012965:Sodium Chloride; D009638:Norepinephrine