Comparative studies on the influence of decapitation, ketamine and thiopental anesthesia on rat heart mitochondria

The influence of decapitation, ketamine and thiopental anesthesia on some properties of rat heart mitochondria was compared. Polarographic analysis were performed, oxygen consumption rates, respiratory control index, ADP : O ratio and oxidation of exogenous NADH were determined. Electronmicroscopic and gasometric examinations were also conducted. Mitochondrial fractions from hearts of decapitated rats oxidized at a generally faster rate and mitochondria from such hearts exhibited a significantly lower RCI value. These differences can be explained through the action of uncoupler(s) present in the decapitated group. A hypothesis linking decapitation with the uncoupling effect of fatty acids released intracellularly during catecholamine-stimulated lipolysis is discussed. No differences in the ADP : O ratio and electronmicroscopic details between the groups were found. Gasometric determinations in both anesthetized groups did not show any marked dysfunction of the respiratory system. It is concluded that decapitation leads to some changes in the functional integrity of rat heart mitochondria. Ketamine and thiopental anesthesia can be used with equal success for the isolation of mitochondria from the heart.