Differential effects of physical and psychological stressors on immune functions of rats.

To study the effects of different types or durations of stressors on immune functions, male Fischer rats were exposed to chronic physical (electric foot shock) or psychological (non-foot shock) stress induced in the communication box. Superoxide production by alveolar macrophages (AMs), mitogen-induced splenic lymphocyte proliferation, and splenic natural killer (NK) cell cytolysis were examined in vitro. Repeated exposure to physical stress suppressed superoxide production by AMs (-58%, p<0.