Beneficial effect of muzolimine in postischemic acute renal failure in rats

Evidence has been presented in the past that muzolimine might act at a localization differently to sulfamoyl-type diuretics and/or with a different or additional mechanism. This is further supported by the fact that at the maximum of the dose-response curves for muzolimine and furosemide in rats, a combination of maximal oral doses still results in significantly higher sodium excretion. To further substantiate that this aspect of muzolimine is of relevance, e. g. for the therapy of acute renal failure, muzolimine treatment by food or implanted osmotic minipumps was employed in an obstructive model of severe renal ischemia in rats. Acute renal ischemia was induced in Wistar rats by clamping the left renal pedicle for 60 minutes with a microsurgery clamp. The right kidney had been removed four days before ischemia. Clearance data were obtained on the first, third and on the ninth to fourteenth days after ischemia in the surviving animals. Renal ischemia resulted in anuria, increased mortality and impaired renal function with histopathologically apparent tubular obstruction in the untreated controls. Treatment with muzolimine by food (in a concentration of 800 ppm for four days) and additional oral gavage one hour prior to ischemia prevented the sequelae of ischemia to a great extent. Similar beneficial effects could be obtained by therapeutic implantation of osmotic minipumps ensuring administration of 0.44 micrograms muzolimine/h per animal. These results in rats further support the suggestion that muzolimine might act differently to sulfamoyl-diuretics. Furthermore, they strongly implicate muzolimine as the diuretic of choice in acute renal failure.