Digitalis-like biological activity in rat cerebellum.
The cytosolic fraction of rat cerebellum possesses a factor(s) which is capable of inhibiting synaptosomal Na,K-ATPase activity, competing with [3H]ouabain binding to rat brain synaptosomes, and inducing positive inotropy in guinea pig atrial strips. These results demonstrate the existence of a ouabain-like principle in rat cerebella. The inhibitory activity of the factor was found to be partially thermolabile and diminished by a proteolytic agent, and the activity could be augmented by increasing concentrations of Mg2+, suggesting a regulatory mechanism for the endogenous digitalis-like principle.
D000818:Animals; D016275:Atrial Function; D001798:Blood Proteins / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D002298:Cardenolides; D002531:Cerebellum / Q000378:metabolism*; D004077:Digoxin; D006168:Guinea Pigs; D006325:Heart Atria / Q000187:drug effects; D066298:In Vitro Techniques; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D009200:Myocardial Contraction / Q000187:drug effects; D010042:Ouabain / Q000378:metabolism; D051381:Rats; D012503:Saponins; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors*; D013574:Synaptosomes / Q000378:metabolism*
D001798:Blood Proteins; D002298:Cardenolides; D012503:Saponins; C034504:digoxin-like factors; D010042:Ouabain; D004077:Digoxin; D000254:Sodium-Potassium-Exchanging ATPase; D008274:Magnesium