[Comparison of the mechanism of cardiotonic action of the fraction 3 of MAI-BAO and digoxin on rat isolated heart]. / Comparison du mecanisme de l'action cardiotonique de la fraction 3 de MAÏ-BAO et de la digoxine sur le coeur isole de rat.

UNLABELLED: MAI-BAO (MB) is a beverage obtained by fermentation of sweet Camellia sinensis tea by the Tea-Mushroom treasure. The action of the chromatographic fraction 3 of MAI-BAO (MB-F3) is cardiotonic. AIMS: To compare the mechanism of cardiotonic activity of MB-F3 and digoxin (Dx) in rats. MATERIALS AND METHODS: MB-F3 obtained by gel chromatography on sephadex G-50 and digoxin are used to infuse the isolated rat heart with the device Langendhorff for the record of cardiac contractions. The biochemical mechanism of cardiac effect of MB-F3 and Dx was determined by measuring phosphorus by the method of Sumner. RESULTS: MB-F3 has a significant positive inotropic effect (P<0.05) as Dx (P <0.01) with respective effective Doses 50% 1mg/ml and 10-6 mg/ml. Furthermore, MB-F3 exerts a competitive inhibition on the ATPase-Na+/K+ less than Dx (P<0.05). CONCLUSION: MB-F3 exerted digitalis-like effect less than digoxin on the rat heart.