Abstract
E. Habermann, M. Hudel and M.-E. Dauzenroth. Palytoxin promotes potassium outflow from erythrocytes, HeLa and bovine adrenomedullary cells through its interaction with Na +, K +-ATPase. Toxicon 27, 419–430, 1989.—Erythrocytes from four mammalian species were compared with regard to K +loss triggered by palytoxin, to Na +, K +-ATPase activity, and to ouabain sensitivity of both events. Palytoxin sensitivity ( ec 50) decreased in the order rat, man (≈ 1 pM) > cattle (≈ 500 pM) > dog (> 10 nM). Na +, K +-ATPase activity, as measured by Rb uptake, was in the series rat > man > cattle > dog. The glycoside potently inhibited both palytoxin action and ATPase activity in man, cattle and dog erythrocytes, but weakly in those from rats. Ca 2+ promoted the palytoxin effects on all erythrocytes. As shown for human erythrocytes, Sr 2+ and Ba 2+ but not Mg 2+ can substitute for Ca 2+, and sucrose can substitute for sodium chloride. Human HeLa and bovine adrenomedullary cells also lost their K + within a few min when exposed to palytoxin (1–10 pM). Ouabain acted as a palytoxin antagonist on both cell types. We conclude that: (a) the ouabain binding site of Na +, K +-ATPase is part of the palytoxin receptor in every cell type tested, (b) high palytoxin sensitivity is not necessarily accompanied by high ouabain sensitivity, and (c) active ion transport is not a precondition for the action of palytoxin or for its inhibition by ouabain.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call