Contribution of A1-adenosine receptor in the development of renal functional disturbances during the early hours of reperfusion following ischemia in anaesthetized rats

This investigation was designed to determine the effects of a selective A1-AR antagonist (DPCPX) on renal hemodynamic and excretory dysfunctions induced during the early hours of ischemia/reperfusion (I/R).

In this experimental research, rats were anaesthetized by sodium pentobarbital, and their renal arteries were, then, occluded for 30 min, four hours after the reperfusion period. There was a clearance period during the last one hour of reperfusion period throughout which urine was collected under 30-mm of paraffin, and arterial blood samples were taken during its beginning and end. Animals were divided into four groups; DPCPX (2 mg/kg) or normal saline were injected 30 min before renal ischemia to the two groups of I/R+DPCPX and I/R, respectively, and to DPCPX and Sham groups which were subjected to surgery without clamping of renal arteries, respectively.

I/R resulted in elevations of plasma osmolality, plasma concentrations of Na, K, creatinine, and urea, fractional excretions of Na, K, and bicarbonate, absolute bicarbonate excretion, and urinary pH, but it induced reductions in arterial bicarbonate concentration, pH and Pco2, creatinine clearance, absolute excretions of Na and urea, free-water re-absorption, and urinary osmolality in the I/R group in comparison to the Sham group. Comparison between I/R+DPCPX and I/R groups showed that applying DPCPX could improve I/R-induced alterations in most of these parameters.

Activation of A1-AR during the early hours of reperfusion following renal ischemia definitely contributes to the development of disorders in hemodynamics, tubular Na re-absorption, as well as excretions of K, urea, and acid-base.