The importance of the response of the renin‐angiotensin system in determining blood pressure changes with sodium restriction.

Abstract

There is controversy about the efficacy of sodium restriction in the treatment of hypertension. Short‐term restriction of sodium intake in normotensive subjects causes little or no fall in blood pressure. This lack of response of blood pressure to sodium restriction appears to be due, at least in part, to a reactive rise in renin and angiotensin II. In patients with essential hypertension there is suppression of the renin‐angiotensin system particularly as blood pressure becomes more severe. With sodium restriction there is less of a rise in renin and angiotensin II compared with normotensive subjects and patients have a greater fall in blood pressure compared with normotensive subjects but the effect is less in mild compared to severe hypertension. As the formation of angiotensin II can now be blocked by the use of a converting enzyme inhibitor, the combination of moderate salt restriction in conjunction with a converting enzyme inhibitor is likely to be more effective in lowering blood pressure than either treatment on its own.

Blunted Response of the Renin-Angiotensin System and Nitric Oxide Synthesis Related to Sodium Sensitivity in Immunoglobulin A Nephropathy

“…Correlation of urinary excretion of NOX on the diet with a low sodium level with the SSI was not significant (ρ 0.255, p 0.12, n 39). The changes in urinary excretion of NOX were not significantly different in the two groups (low-SSI group, 251 [ 16,414] µmol/day, and high-SSI group, 25 [ 213, 297] µmol/day, p 0.14). The changes in plasma NOX were not different (low-SSI group, 0.8 [ 3.6, 22.3] µmol/l, and high-SSI .…”

“…Reactive increases in PRA and ALD during sodium restriction are important for the maintenance of blood pressure in normotensive subjects (16,17). However, in hypertensive patients, especially sodium-sensitive ones, the reactive increases in PRA and ALD are attenuated and the blood pressure is lowered when sodium intake is restricted (18,19).…”

“…In normotensive subjects with normal renal function, the renin-angiotensin-aldosterone system works to maintain systemic blood pressure during sodium restriction (16,17). However, in hypertensive patients, the renin system is blunted, and systemic blood pressure decreases when the sodium intake is low; the pressure increases when the sodium intake is high (18,19).…”

Factors in the choice of antihypertensive therapy.

“…The introduction of ACE inhibitors revived the argument as to the usefulness of PRA as a marker for their relative effectiveness (Case et al, 1977); much of the clinical work on this has been done by MacGregor and is described elsewhere in this volume (MacGregor, 1987 (Grassi etal., 1985). This, however, does not necessarily help in selecting those patients whose increased sympathetic activity differentiates them from other groups of hypertensive patients, and which might form the basis for drug selection.…”

Review: Salt, blood pressure and the renin-angiotensin system

“…3 The mechanisms for these differences in BP response to salt reduction are not fully understood. It has been suggested that the responsiveness of the reninangiotensin system (RAS) plays an important role, 6 but the sympathetic nervous system, 7,8 the kallikrein-kinin system, 9 the nitric oxide system, 10 and many eicosanoids 11 may also contribute. However, the evidence for many of these is circumstantial, whereas the evidence for the important role of the RAS is substantial and compelling.…”