Lactic Acid Increase in Muscle Under the Influence of Anesthetics.

The increase of lactic acid in resting muscle under the influence of narcotics is a familiar phenomenon with high concentrations of chloroform, and was observed by Meyerhof 1 for alcohol and urethanes in concentrations about 10 times those sufficient for general anesthesia. It has now been found that the lactic acid content of isolated whole muscle of green frogs is increased on the average 20 to 50% by ether, nitrous oxide and ethylene at tensions sufficient for general mammalian anesthesia (0.028 atmospheres ether vapor, 0.85 atmospheres ethylene, 1 atmosphere nitrous oxide). This increase is comparable to that produced by chloroform at an equivalent tension (0.01 atmospheres). The lactic acid increase is greater with higher tensions of these anesthetics, being 75 to 105% when 5 to 8 times the anesthetic tension is used. These increases occur with 1/2-2 hours exposure to the anesthetic, and do not seem to be greater with the longer exposures. They are measured by comparing the total lactic acid content of several small muscles (one of each of several pairs) exposed to narcotics, with the lactic acid content of the mates to these muscles not so exposed but otherwise similarly treated.

The possibility that the increased lactic acid content is caused wholly by narcotic interference with the oxidative removal of lactic acid is eliminated by the fact that the increase under the influence of narcotics, especially in high concentrations, is very much greater than the increase when all oxidations are prevented by cyanide; and by the second fact that treating both sets of muscles with cyanide before application of narcotic to one of them, or keeping them in an atmosphere of nitrogen throughout the experiment, seems not to decrease the difference between the amounts of lactic acid in the two sets.