BETA-ADRENOCEPTOR BLOCKING PROPERTIES OF MK-761

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  • 1 January 1979
    • journal article
    • research article
    • Vol. 211  (1) , 195-199
Abstract
MK-761 is a new class of compound which has .beta.-adrenoceptor antagonist and vasodilating properties in a single molecule. The compound has in vitro .beta.-adrenoceptor blocking activity in the isolated cat heart papillary muscle and isolated rat atria. Unlike propranolol, it did not depress contactile force. Intrinsic sympathomimetic activity was not seen in vitro, (isolated cat papillary muscle, isolated atria) but the compound has some intrinsic sympathomimetic activity as it slightly increased heart rate in reserpinized rats. MK-761 was about as potent as timolol and pindolol in blocking cardiac and vascular .beta.-adrenergic receptors in anesthetized dogs. The drug was not cardioselective. Oral .beta.-adrenoceptor blocking activity was seen in rats at doses similar to those which decreased blood pressure.