Alteration of tissue carnitine content following anaesthesia with barbiturate and surgery in rat

Abstract

The hypercatabolic state leads to urinary carnitine loss. Anaesthesia and surgical intervention causes stress conditions. The stress is accompanied by the alteration of hormone states and energy processes. Carnitine, which physiologically promotes the fatty acid metabolism and so plays a very important role for the heart, can be involved in these alterations. The aim of this study was to examine the effects of anaesthesia and surgical intervention on carnitine distribution in the tissues. Rats were anaesthetized with thiopental and surgical intervention was performed on the femoral artery and vein. Carnitine levels, as well as parameters indicative of energy metabolism, were measured in the blood and tissues. It was found that anaesthesia and surgical intervention increased the corticosterone levels in blood and decreased the carnitine levels in blood and kidney. Carnitine accumulated in the liver, whereas in heart and skeletal muscle it was redistributed by a decrease in the acylated form and an increase in the free form. Glycogen was accumulated in cardiac and skeletal muscle. Compared to anaesthesia, the surgical intervention increased glycogen storage and carnitine redistribution in heart and skeletal muscle. Moreover, it caused a decrease in cholesterol and an increase in urea in the blood. The fall in blood and kidney carnitine levels indicates a possible depletion of carnitine. The deacylation of carnitine in heart and skeletal muscle represents an important alteration in heart and muscle energetic metabolism. The increase in urea is a consequence of high proteolysis. Acylcarnitine administration during pre- and operative step might prevent the loss of carnitine, promoting the heart energetic metabolism and reducing the proteolysis. Moreover, in accordance with a recent interpretation of carnitine action as a membrane-stabilizing agent, the acylcarnitine supply could reduce the risk of "oedema" that follows the anaesthesia and surgical intervention.