EFFECTS OF VANADATE, OUABAIN AND AMILORIDE ON THE CONTRACTION OF THE RAT TESTICULAR CAPSULE TO OXYTOCIN

1. The modification of the contraction of the rat testicular capsule to oxytocin (OT) by vanadate (0.7, 7 and 70-mu-M), ouabain (0.1 mM), and amiloride (10-mu-M to 1 mM) have been studied. 2. OT (1 nM-6-mu-M) and vanadate (10-mu-M-3 mM) induced contraction of the rat testicular capsule in a dose-dependent way (ED50: 188 +/- 66 nM and 82.8 +/- 7.4-mu-M, respectively). 3. Vanadate (0.7, 7 and 70-mu-M) and ouabain (0.1 mM) increases the contractile effect of OT (50 and 200 nM). 4. Amiloride (10-mu-M-1 mM) inhibit, in a dose-dependent way, the OT-contraction. 5. Amiloride (10-mu-M or 50-mu-M) block the ouabain but not the vanadate potentiation to OT.