Effects of beta-adrenergic stimulation on the acutely obstructed ureter indogs

The objective of the present study was to evaluate the effects of a selecti ve beta(3)-adrenoceptor agonist, (R,R)-5-[2-[[2-(3-chlorophenyl)- 2- hydrox yethyl]- amino] propyl]-1,3-benzodioxole-2,2-dicarboxylate (CL 316243), on the acutely obstructed ureter in anesthetized dogs. After a complete ureter al obstruction produced by the inflation of a balloon catheter placed withi n the left lower ureter, the intraluminal ureteral pressure gradually rose to reach a plateau of similar to 52.5 mm Hg. Intravenous administration of isoproterenol (a nonselective beta-adrenoceptor agonist; 10 mu g/kg) and CL 316243 (1 mu g/kg) significantly decreased this elevated ureteral pressure (by 74.1 and 77.2%, respectively), with the reduction more sustained with CL 316243 than with isoproterenol. In addition, under both isoproterenol an d CL 316243, urine flow (which had been interrupted by the balloon) was res umed, resulting in further sustained decreases in ureteral pressure. The me an blood pressure decreased and heart rate increased after the administrati on of both drugs, but these changes were greater in the isoproterenol group than in the CL 316243 group. In contrast, i.v. administration of butylscop olamine (an anticholinergic agent; 1000 mu g/kg) had no evident effects on ureteral pressure or on urine flow. The increase in left kidney weight seen after ureteral obstruction was suppressed by CL 316243. We conclude that t he selective beta(3)-adrenoceptor agonist tested appears to be more useful than isoproterenol for reducing ureteral pressure above the obstructed site and for promoting ureteral relaxation and increasing urine flow around the point of obstruction in dogs.