Inhibitors of the Sodium Pump: Toxins, then Drugs, and now hormones

Abstract

The toxic properties of plants such as squills and the foxglove have been known since antiquity. These poisons induce emesis, diarrhea and death through cardiac arrhythmia. African hunters have extracted a toxin from the Strophantus and used it as arrow poison. All these plants and many others contain glycosylated steroids that we now designate as cardiotonic steroids, because of their common property of inducing an increase of the strength of contraction of the myocardium. The therapeutic use of digitalis has first been described 200 years ago by Withering (1785) and since then digitalis derivatives have been extensively used for the treatment of congestive heart failure. The most commonly used compounds are digoxin for clinical purpose, and ouabain for laboratory experiments. Intoxication by digitalis-like compounds mainly occurs as the results of inappropriate dosage or because of accidental or suicidal acute intoxication. Accidental poisoning also occurs because of confusing cardiotonic steroid containing plants for herbal teas.