Abstract
Cardiac responses to vasoactive substances on the whole animal are due to results of their direct and indirect actions. On the other hand, the responses on the isolated heart preparation are due to the direct cardiac effects. The isolated, blood-perfused dog atrial muscle preparation is useful for pharmacologically analyzing direct cardiac effects of active substances. When the drug was applied intravenously to the donordog, the changes in the donor's blood pressure and heart rate, andisolated atrial rate and developed tension are simultaneously observed. Thus, direct and indirect cardiac effects of the drug were readily analyzed pharmacologically. In the present time, I demonstrated the effects of intravenous lidocaine, pentobarbital, nitroprusside, prostacyclin and glucagon on whole animals and isolated atria.
