Effects of Anesthetics on Myocardial Catecholamines

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Abstract
In nonreserpinized dogs the cate-cholamine content was greater in the atrial than in ventricular tissue; the atrial-ventricular ratio was approximately 1.8:1 for epinephrine and 2:1 for nor epinephrine. The ratio of norepinephrine to epinephrine in atrial and ventricular tissues was 10:1. In nonreserpinized dogs, the catecholamine contents of cardiovascular tissues were not significantly changed following thiopental anesthesia, but norepinephrine content was significantly increased during ether and cyclopropane anesthesia in contrast to the significant depletion of epinephrine following ether, cyclopropane and halothane, in that order of magnitude. In the reserpinized group before anesthesia, 95 per cent of norepinephrine stores was depleted, with some reduction in epinephrine. Anesthetics exerted no effect upon the catecholamine contents of reserpinized animals. The unaltered tissue epinephrine content of the reserpinized dogs was in strong contrast to the depletion after ether and cyclopropane in nonreserpinized dogs. The mechanisms of these changes are discussed with reference to the hemodynamic effects of anesthetic agents.