EFFECTS OF NARCOTICS AND CONVULSANTS ON TISSUE GLYCOLYSIS AND RESPIRATION

¹ Allan Memorial Institute, Montreal
² Department of Neurology and Neurosurgery, McGill University, and the Montreal Neurological Institute, Montreal, Canada

Glycolysis by brain tissue in the presence of oxygen is greatly increased by low concentrations of various narcotics. Maximum glycolytic rate, equal to or exceeding the normal rate of anaerobic glycolysis, occurs when the oxygen uptake is about 50 per cent inhibited by the drug. The rate of glycolysis is lowered again, and the oxygen uptake further depressed, by higher concentrations of drug. Anaerobic glycolysis is unaffected or slightly accelerated by low drug concentrations but is inhibited by concentrations greater than those which cause maximum aerobic glycolysis. The concentrations at which these effects occur vary from drug to drug. The effects on glycolysis and respiration are reversible at low concentrations but irreversible at concentrations which inhibit glycolysis. Pentobarbital exerts similar effects on the metabolism of testis and kidney tissue.

Oxygen uptake is increased in the presence of succinate, ascorbate or glutathione in the presence or absence of drug. Succinate does not affect the aerobic glycolysis produced by pentobarbital; ascorbate and glutathione reduce it.

Convulsant drugs tested do not markedly affect respiration or glycolysis except at relatively high concentrations.