CONCURRENT CHANGES IN HYPOTHALAMIC AND CARDIAC CATECHOLAMINE LEVELS AFTER ANESTHETICS, TRANQUILIZERS AND STRESS IN A SUBHUMAN PRIMATE

¹ Laboratory of Neurochemistry, Cleveland Psychiatric Institute, and School of Medicine, Western Reserve University, Cleveland, Ohio

Statistical comparisons were made of concurrent changes in hypothalamic and cardiac catecholamine levels after anesthetics, tranquilizers, stress and the inhibition of stress depletions by pretreatment with tranquilizers. Ninetysix adult squirrel monkeys (Saimiri sciureus) were used for the 4 main experiments. Hypothalamic and cardiac norepinephrine (NE) and epinephrine levels were evaluated after 1-hr exposure to ether, Fluothane or electric shock, and 4 hr after these drug and stress treatments to determine the stage of recovery. One-hour exposure to electric shock resulted in significant NE depletions in both the 1-hr and 4-hr recovery subgroups. Although 1-hr exposure to ether or Fluothane produced no significant depletions, a significant decrease was observed 4 hr later in the 4-hr recovery from the Fluothane subgroup. One control and three experimental groups were also sacrificed 12 hr after a single injection of chiorpromazine (CPZ) (15 mg/kg i.p.) or reserpine (10 mg/kg i.p.), or after 12 hr of isolation. For establishing the drug inhibition of electric shock effects, one group was injected with CPZ, and one group with haloperidol (2.5 mg/kg i.p.), subjected to 1 hr of electric shock and sacrificed. Twelve hours of isolation and reserpine resulted in significant catecholamine depletions in the hypothalamus and heart. Pretreatment with CPZ and haloperidol effectively inhibited electric shock depletions in the hypothalamus as well as in the heart. Statistical tests of concordance also indicated significant correlations between changes in hypothalamic and changes in cardiac NE levels after the anesthetics, tranquilizers, stress and inhibition of stress treatments.