1. To evaluate whether sodium intake can modulate the action of endogenous kinins on renal function and haemodynamics, a receptor antagonist of bradykinin was infused in conscious normotensive rats maintained on either a normal or a low sodium diet.
2. The antagonist inhibited the hypotensive effect of exogenously administered bradykinin. It did not change the vasodepressor effect of acetylcholine, dopamine or prostaglandin E2.
3. The antagonist did not affect mean blood pressure, glomerular filtration rate, renal blood flow or urinary sodium excretion, in rats on sodium restriction. It did not change mean blood pressure, glomerular filtration rate or urinary sodium excretion, but decreased renal blood flow, in rats on a normal sodium intake.
4. The kallikrein–kinin system has a role in the regulation of renal blood flow in rats on a normal sodium diet.