Effect of interleukin-1beta on functional activity of lymphoid structures in the gastrointestinal tract of rats during acute emotional stress.

We studied the effect of interleukin-1beta on functional activity of lymphoid structures in the gastrointestinal tract of rats with various behavioral parameters during stress of simultaneous immobilization and electrocutaneous stimulation. Morphofunctional characteristics of lymphoid tissue were estimated by studying elimination of intraperitoneally injected Chinese ink particles into the mesenteric lymph nodes and wall of the jejunum. Intraperitoneal injection of interleukin-1beta (5 mug/kg, 10(8) U/mg) was accompanied by accumulation of Chinese ink in the mesenteric lymph nodes of unstressed passive and active rats. The observed changes reflect an immunostimulatory effect of this cytokine. Acute stress was followed by an increase in the number of ink particles in the mesenteric lymph nodes and wall of the jejunum in behaviorally active rats. Under these conditions, the number of ink particles was elevated only in the mesenteric lymph nodes of passive specimens. As differentiated from passive animals, pretreatment of active rats with interleukin-1beta before acute stress was followed by the increased elimination of Chinese ink (antigenic material) from the abdominal cavity to the lymph nodes and through the wall of the jejunum. These data illustrate specific features of immune mechanisms for the stress response in mammals with various behavioral characteristics.