Intrarenal adenosine produces hypertension via renal nerves in the one-kidney, one clip rat.

Abstract

The afferent renal nerves enhance sympathetic activity in the one-kidney, one-clip hypertensive rat. We have also found adenosine-sensitive nerve endings in the renal pelvis that, when stimulated, increase sympathetic activity producing hypertension. To determine whether adenosine, which is excreted when renal blood flow is reduced, activates the afferent renal nerves in one-kidney, one-clip hypertension, urinary adenosine concentration was lowered by infusing adenosine deaminase into the renal artery. Urinary adenosine concentration was threefold greater in one-kidney, one-clip hypertensive animals compared with normotensive controls. Intrarenal infusion of adenosine deaminase in one-kidney, one-clip rats lowered urinary adenosine to an undetectable level and attenuated the hypertension. Both plasma norepinephrine levels and the fall in mean arterial pressure after ganglionic blockade decreased during intrarenal adenosine deaminase infusion in one-kidney, one-clip animals. Renal denervation in one-kidney, one-clip animals prevented the changes in mean arterial pressure and plasma norepinephrine levels during intrarenal adenosine deaminase infusion. In contrast to findings in hypertensive animals, intrarenal infusion of adenosine deaminase produced no change in arterial pressure in normotensive controls. These data indicate that urinary adenosine concentration is enhanced in one-kidney, one-clip hypertension and suggest that when urinary adenosine concentration is lowered, sympathetic activity and hypertension became attenuated in this model if the renal nerves are intact.