Effects of adenine nucleotides on contractibty of norma I and post ischemic myocardium

Rapid deterioration of myocardial contractility occurs when heart muscle is subjected to hypoxia and ischemia.‘-* Several investigatorss-8 have reported diminished stores of creatine phosphate (CP) and adenosine triphosphate. (ATP) in hypoxic failing hearts. In skeletal muscle, it has been shown that ATP is the immediate source of energy for contraction and is rapidly replenished by CP hydrolysis.9 Recent work on isolated cardiac muscle suggests that CP hydrolysis may operate in a similar manner to replenish the ATP used in myocardial contraction.lO If ATP is the immediate source of energy for contraction, the deterioration in the mechanical function of ischemic hearts may, to a certain extent, be causally related to the depletion of high-energy phosphates. We investigated the effect of adenine nucleotides on the force development of normal and postischemic myocardium.