EFFECTS OF VARIOUS ANESTHETIC REGIMENS ON TISSUE ANTIOXIDANT ENZYME-ACTIVITIES

It has been suggested that oxidative processes are involved in a varie ty of pathological conditions, notably ischemia-reperfusion injury. Mo reover, anesthetics appear to exert differential effects on the severi ty of such injury, these being unlikely wholly attributable to their d ifferential effects on cardiovascular or microcirculatory status. It i s possible that these variable effects of anesthetics on this type of injury may be due, at least in part, to changes in the production of f ree radicals and/or in their detoxification by endogenous antioxidant enzymes. We have attempted to explore the latter possibility by measur ing activities of catalase, superoxide dismutase (SOD), glutathione pe roxidase (GPX) and glutathione reductase in normal heart tissue and re d cells obtained from rats anesthetized using a variety of agents (CO2 , halothane, pentobarbital or ether). For comparison, analyses were al so performed on tissues from unanesthetized animals rendered unconscio us by stunning prior to sacrifice. Results indicated that myocardial S OD activity was significantly greater in halothane-anesthetized as com pared with CO2-anesthetized animals. Red cell SOD activities did not s how such differences. However, red cell GPX activity was found to be g reater in halothane-anesthetized than in pentobarbital-anesthetized ra ts. In general, however, antioxidant enzyme activities measured ex viv o were minimally affected by the use of anesthetics prior to euthanasi a. Our findings, therefore, do not support the proposal that the influ ence of anesthetics on the course of ischemia-reperfusion injury invol ves effects at the level of enzymatic antioxidant components.