Contribution of sodium to the mechanism of one-kidney, renal-wrap hypertension

Abstract

The early and chronic stages of one-kidney, figure-8 renal-wrap hypertension were studied during low or normal dietary sodium intake in rats. The renal-wrap procedure caused a significant elevation in arterial pressure at 3 and 28 days postwrap with normal sodium diet. Sodium-depleted rats did not experience an increased arterial pressure following renal wrapping. Blockade of angiotensin II receptors with [Sar1-Ala8]angiotensin II caused a greater decrease in arterial pressure in the sodium-depleted, renal-wrapped animals compared with sham-operated rats. In sodium-replete rats, angiotensin receptor blockade did not lower arterial pressure. Total ganglionic blockade decreased arterial pressure significantly more in the wrapped animals than in the sodium-replete sham-operated rats and the wrapped or sham-wrapped, sodium-deplete animals. Thus the early and chronic phases of normal sodium, one-kidney, figure-8 renal hypertension are supported by an increased sympathetic nervous system function. These observations suggest that sodium is necessary for the development of one-kidney, figure-8 renal-wrap hypertension and that the presence of sodium in the diet permits a functional activation of the sympathetic nervous system in response to the renal-wrap procedure.