The interrelationships between chronic restraint stress and reserpine sedation.

The General Adaptation Syndrome (G.A.S.) was characterized for chronic forced restraint stress in normal and reserpinized (1 mg/kg, I.P.) male albino rats. This was accomplished by analyzing the interrelationships among brain neurohumoral levei1 (serotonin (5-HT) and norepinephrine (NE) ), serum corticosterone (KS) levels, and various organ weights such as thymus, testes, pituitaries, and adrenals. Reserpine was observed to prevent normal rats from adapting to this stress (mortality rate was 50~) possibly via inanition. It was suggested that the overall non-adaptive effects produced could ultimately be due to the ability of reserpine to induce a chemical sympathectomy. Thus, by depleting the A.N.S. of accessible NE, an animal would be unable to respond to a severe change in environment. Control animals demonstrated both behavioral and neurochemical adaptation in response to this stress. Initial excitation associated with restraint was related to increased brain 5-HT levels and decreased brain NE levels. As the experiment progressed, stress animals became less excitable and easier to handle which was also associated with the return of both bra in am in es to norm al levels. In contrast, reserpinized animals subjected to chronic restraint stress became progressively rrore excitable and diff1cul t to handle as the experiment proceeded. This behavior can