EXPERIMENTAL INDUCTION AND TERMINATION OF ACUTE PSYCHOLOGICAL STRESS IN HUMAN VOLUNTEERS - EFFECTS ON IMMUNOLOGICAL, NEUROENDOCRINE, CARDIOVASCULAR, AND PSYCHOLOGICAL PARAMETERS

The present research investigated the effects of controlled experiment al manipulations of stress on biological and psychological reactions. Fifty young adult male volunteers were exposed to a 12-min period of s tress induced by the threat of an unavoidable, painful electric shock. A 12-min period without this threat preceded or followed the stress p eriod. Blood was drawn during the il th and the 12th minute of each pe riod. Anticipatory threat led to significant elevations in the proport ions and cytotoxic activity of natural killer (NK) lymphocytes, plasma epinephrine levels, pulse rate. and reported level of tension. and to a reduction in the CD4/CD8 ratios. The no-threat period induced a ret urn to baseline values for epinephrine, pulse rate, and tension, and l ower than baseline levels for cytotoxic activity of NK lymphocytes, wi thin a similarly short time span. The findings underline the rapidity with which physiological changes may transpire in the course of a brie f and acute period of psychological stress, and the rapidity of their reversal upon relief from the stressor. (C) 1998 Academic Press.