The effects of decapsulation on ion movements across the lens of the toad, Bufo marinus. Influence on drug actions.

The lens of the toad Bufo marinus, like that of mammals, slowly gains Na and loses K when incubated in vitro. This process is facilitated by a low temperature (5° C), iodoacetate, cyanide, or ouabain. The ratio of Na/K exchange is about 1.5. Decapsulation of the lens (following brief incubation in collagenase) did not change its ionic content. Such lenses maintained their Na levels in vitro better than normal ones and lost K at a similar rate, so that the Na/K exchange was about 0.7. Ouabain still exerts its effects in the decapsulated lens, while ethacrynic acid facilitated Na accumulation more so than in the intact tissue. Ethacrynic acid did not alter K loss. Acetylcholine, eserine, pilocarpine, phospholine iodide, and atropine did not alter the movements of Na or K across intact or decapsulated lenses of the toad. Demecarium promoted extra accumulation of Na in both situations.