Differential expression of renal adenosine A(1) receptors induced by acuterenal failure

The distribution of renal adenosine A, receptors was investigated in rats w ith glycerol- or mercuric chloride (HgCl2)-induced acute renal failure. Rec eptors were localised by autoradiography using [H-3]8-cyclopentyl-1,3-dipro pylxanthine ([H-3]DPCPX), a selective A(1) adenosine receptor antagonist. I n saline-injected control animals, significant labelling with [H-3]DPCPX wa s detected in glomeruli, the inner stripe of outer medulla, and the inner m edulla. Sixteen hours following induction of glycerol-induced acute renal f ailure (ARF), a 34% increase in labelling in glomeruli was noted compared t o saline-injected controls, and by 48 hr, glomerular labelling had increase d by 200%. In addition, 48 hr following glycerol injection, significant lab elling was now detected in the cortical labyrinth and medullary rays whilst , in the inner medulla, labelling had decreased by 34%. By contrast to glyc erol-induced ARF, the only significant change noted 48 hr following inducti on of HgCl2-induced ARF was a 39% decrease in labelling in the inner medull a. It is concluded that glycerol-induced ARF results in differential expres sion of renal adenosine A(1) receptors with increased expression in the cor tex and reduced expression in the inner medulla. Increased density of A(1) receptors in glomeruli may account, at least in part, for the increased ren al vasoconstrictor response to adenosine and depressed glomerular filtratio n rate noted previously in this type of acute renal failure. (C) 2000 Elsev ier Science Inc.