Effects of furosemide on blood pressure in anephric rats.

This study has been performed in order to evaluate whether furosemide can induce changes in blood pressure independently of its diuretic effects,and whether its pressor effects are connected with the ability to synthetize renal prostaglandins. The experiments were performed in four groups of volume-expanded rats: the first (n.5) had bilateral ligation of the renal vessels; the second (n.8) had bilateral ligation of the ureters; the third group (n.6) had ureters ligation after pre-treatment with indomethacin; the fourth group (n.2) received a pre-treatment with captopril. After blood pressure stabilization, furosemide was administered i.v. (0.125 mg/100 g. of body weight). Indirect readings of the blood pressure were obtained at 1, 2, 3, 4, 5, 7.5, 10, 15, 20 min. After furosemide administration, blood pressure fell down quickly in the rats with ureteral ligation and in those with captopril pretreatment, while the tensive response to furosemide was blunted by the indomethacin treatment. In conclusion, furosemide can reduce blood pressure by a mechanism non related with its diuretic properties, which, however, requires the integrity of the renal connections with the circulatory system.