Background:

SCH00013 is a cardiotonic agent that primarily acts via an increase in myofibrillar Ca++ sensitivity, have a significant Ca(2+)sensitizing effect at pH 7.2 to 7.4.In vitro: SCH00013 at 10-4 M increased the systolic cell shortening by 52% above the base-line value in association with an insignificant increase in the systolic fluorescence ratio by 15% above the control. [1]In vivo: The positive inotropic effects of 10?4 M SCH00013 on the dog and rabbit were 38% and 29% of the maximal response to isoproterenol. [1] CH00013 elicited a positive inotropic effect at more than 0.3 and 1 mg/kg, i.v. in normal and heart failure dogs. [2] SCH00013 elicits a positive inotropic effect mainly through an increase in myofilament Ca2+ sensitivity without increasing the heart rate. [3]

[1]. Sugawara H et al. A novel cardiotonic agent SCH00013 acts as a Ca++ sensitizer with no chronotropic activity in mammalian cardiac muscle. J Pharmacol Exp Ther. 1998 Oct;287(1):214-22. [2]. Tadano N et al. SCH00013, a novel Ca(2+) sensitizer with positive inotropic and no chronotropic action in heart failure. J Pharmacol Sci. 2005 Jan;97(1):53-60. [3]. Endoh M et al. Pharmacology of SCH00013: a novel Ca2+ sensitizer. Cardiovasc Drug Rev. 2001 Winter;19(4):345-66.