Impaired renal vascular reactivity in prehypertensive Dahl salt-sensitive rats.
We have previously shown that renal vascular resistance is less in Dahl salt-sensitive rats than salt-resistant rats fed 1% NaCl diets; however, renal vascular resistance increases before nonrenal vascular resistance as salt-sensitive rats develop hypertension when fed 8% NaCl diets. When salt-resistant rats are given 8% NaCl diets, renal vascular resistance decreases. The current study reports effects of atrial natriuretic peptide, nitroprusside, norepinephrine, angiotensin II, and endothelin-1 on renal and nonrenal vascular resistance in prehypertensive salt-sensitive and salt-resistant rats given 1% NaCl diets; doses used did not affect blood pressure. Resistance of nonrenal vessels in salt-sensitive and salt-resistant rats responded similarly to dilators or constrictors. However, atrial natriuretic peptide and nitroprusside decreased renal vascular resistance of salt-resistant rats (by 65%, p less than 0.01) but not that of salt-sensitive rats. Norepinephrine, angiotensin II, and endothelin-1 increased renal vascular resistance in salt-sensitive rats by 126%, 135%, and 135%, respectively (p less than 0.01); norepinephrine and angiotensin II did not change renal vascular resistance of salt-resistant rats, but endothelin-1 decreased renal vascular resistance in salt-resistant rats by 30% (p less than 0.01). Reactivity of nonrenal blood vessels in prehypertensive salt-sensitive and salt-resistant rats was similar when infused with dilators or constrictors in doses used. By contrast, renal vessels of salt-sensitive rats did not dilate in response to atrial natriuretic peptide and nitroprusside but were hypersensitive to norepinephrine and angiotensin II. Endothelin-1 caused renal vasoconstriction in salt-sensitive rats and renal vasodilation in salt-resistant rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Simchon
S
S
Department of Medicine, New York University Medical Center, College of Physicians and Surgeons, Columbia University, NY 10016.
Manger
W M
WM
Shi
G S
GS
Brensilver
J
J
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology; D002302:Cardiac Output / Q000187:drug effects; D016232:Endothelins / Q000494:pharmacology; D006973:Hypertension / Q000209:etiology*; D008297:Male; D009599:Nitroprusside / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012079:Renal Circulation / Q000187:drug effects*; D014655:Vascular Resistance / Q000187:drug effects*
D016232:Endothelins; D000804:Angiotensin II; D009599:Nitroprusside; D009320:Atrial Natriuretic Factor; D009638:Norepinephrine