Anesthetic effects on liver and muscle glycogen concentrations: rest and postexercise.

We compared the effects of three different anesthetics (halothane, ketamine-xylazine, and diethyl ether) on arterial blood gases, acid-base status, and tissue glycogen concentrations in rats subjected to 20 min of rest or treadmill exercise (10% grade, 28 m/min). Results demonstrated that exercise produced significant increases in arterial lactate concentrations along with reductions in arterial Pco2 (PaCO2) and bicarbonate concentrations in all rats compared with resting values. Furthermore, exercise produced significant reductions in the glycogen concentrations in the liver and soleus and plantaris muscles, whereas the glycogen concentrations found in the diaphragm and white gastrocnemius muscles were similar to those found at rest. Rats that received halothane and ketamine-xylazine anesthesia demonstrated an increase in Paco2 and a respiratory acidosis compared with rats that received either anesthesia. These differences in arterial blood gases and acid-base status did not appear to have any effect on tissue glycogen concentrations, because the glycogen contents found in liver and different skeletal muscles were similar to one another cross all three anesthetic groups. These data suggest that even though halothane and ketamine-xylazine anesthesia will produce a significant amount of ventilatory depression in the rat, both anesthetics may be used in studies where changes in tissue glycogen concentrations are being measured and where adequate general anesthesia is required.