Myocardial Metabolic Changes During Acute Hemorrhage

Abstract

Cardiac mitochondrial oxidative enzyme systems, myosin, ATPase, actin and myocardial adenosine nucleotides contents were studied after acute hemorrhage for 3-hour period, in dogs. The mitochondrial succi-nate dehydrogenase, NADH-cytochrome "c" reductase (of Mahler et al), and cytochrome oxidase activities were decreased. Myosin ATPase and the ability of actin to activate myosin ATPase activity were also affected by acute hemorrhage for 3-hour period (femoral arterial pressure of 40 mm Hg). Cardiac creatine phosphate and adenosine triphosphate levels were lower than the control group, during acute hemorrhage. Mitochondrial succinate dehydrogenase, cytochrome oxidase, and nico-tinamide adenine diphosphate NADH-cytochrome "c" reductase activities were studied according to the methods of Bonner, L. Smith, and Mahler, respectively, using a Zeiss spectrophotometer and recorded on a Vari-cord model 43 recorder, at 26[degree], C. Myocardial CP and ATP, ADP, and AMP were studied according to the method of Kalckar. These findings plus current data obtained from our lab suggest that, in all probability, the initial myocardial deterioration may be located in the mitochondrial system.