Sugar moiety of cardiac glycosides is essential for the inhibitory action on the palytoxin-induced K+ release from red blood cells.
Palytoxin (PTX), a highly toxic and sugar-containing substance isolated from Palythoa tuberculosa, caused K+ release from rabbit red blood cells. Cardiac glycosides, such as ouabain, convallatoxin, cymarin, digoxin and digitoxin, inhibited the PTX-induced K+ release. Their corresponding aglycones did not inhibit the K+ release, but antagonized the inhibitory effect of the glycosides. All these cardiotonic steroids equally inhibited the activity of (Na+ + K+)-ATPase prepared from hog cerebral cortex. These results suggest that the sugar moiety of the cardiac glycosides is important for the inhibitory effect on the K+ release induced by PTX and that the inhibition is not related to their inhibitory potency on the (Na+ + K+)-ATPase activity.
D000178:Acrylamides; D000818:Animals; D002301:Cardiac Glycosides / Q000494:pharmacology; D003064:Cnidarian Venoms / Q000494:pharmacology*; D004910:Erythrocyte Membrane / Q000187:drug effects*; D011188:Potassium / Q000097:blood; D011817:Rabbits; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors* / Q000097:blood; D013329:Structure-Activity Relationship; D000095702:Polyether Toxins
D000178:Acrylamides; D002301:Cardiac Glycosides; D003064:Cnidarian Venoms; D011188:Potassium; D000254:Sodium-Potassium-Exchanging ATPase; C010272:palytoxin; D000095702:Polyether Toxins