Key result
Administration of the selective ETB receptor antagonist A-192621 increased arterial pressure in all rats, an effect not significantly altered by salt intake or ANG II.
Why the study?
Does ETB receptor antagonism affect arterial pressure in ANG II-induced hypertension under different salt intakes in male rats?
Does ETB receptor antagonism affect arterial pressure in ANG II-induced hypertension under different salt intakes in male rats?
The salt sensitivity of angiotensin II-induced hypertension is not mediated by changes in endothelin ETB receptor function.
ETB antagonism raises arterial pressure independently of salt or ANG II in rats; challenges ETB mediation of salt sensitivity but leaves open human relevance.
We showed recently that endothelin (ET)A receptors are involved in the salt sensitivity of ANG II-induced hypertension. The objective of this current study was to characterize the role of endothelin ETB receptor activation in the same model. Male rats on fixed normal (2 meq/day) or high (6 meq/day) salt intake received a continuous intravenous infusion of ANG II or salt only for 15 days. During the middle 5 days of the infusion period, rats were given either the selective ETB receptor antagonist A-192621 or the nonselective endothelin receptor antagonist A-182086 (both at 24 mg x kg(-1) x day(-1) intra-arterially). Infusion of ANG II caused a greater rise in arterial pressure in rats on high-salt intake. The administration of A-192621 increased arterial pressure further in all rats. The chronic hypertensive effect of A-192621 was not significantly affected by salt intake or ANG II. The administration of A-182086 lowered arterial pressure chronically only in rats on normal salt intake receiving ANG II. Thus the salt sensitivity of ANG II-induced hypertension is not caused by changes in ETB receptor function.
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Ballew et al. (2001) studied Angiotensin II-induced hypertension. A-192621 or A-182086 vs. Salt only / ANG II alone was evaluated on Arterial pressure. Administration of the selective ETB receptor antagonist A-192621 increased arterial pressure in all rats, an effect not significantly altered by salt intake or ANG II.
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