THE EFFECTS OF VASOPRESSIN ON THE SHORTCIRCUIT CURRENT ACROSS THE WALL OF THE ISOLATED BLADDER OF THE TOAD, BUFO MARINUS

Abstract

SUMMARY 1. The effects of metabolic inhibitors and ionic changes on the short-circuit current across the toad's bladder have been studied both in the presence and absence of vasopressin. 2. The effects of metabolic inhibitors indicate that the energy for short-circuit current is derived from both glycolysis and oxidative metabolism. 3. Divalent ions play an important part in the maintenance of the resting short-circuit current and of its response to vasopressin. Ca++ or Sr++ are necessary for the former and Ca++ for the latter. 4. Increased concentration of Ca++, Sr++, Mg++ or Ba++ did not inhibit the increment in short-circuit current produced by vasopressin, in contrast to the effect of these ions on water transport. 5. Increase and decrease in potassium concentration inhibited the short-circuit current whether vasopressin was present or not. 6. The correct concentration of sodium on the serosal side of the bladder was necessary to maintain the short-circuit current, but the increment seen when vasopressin was added was not affected by 50% substitution of choline for sodium.