[Changes in duodenal lymphoid structures in rats with various behavioral activity, caused by delta sleep-inducing peptide and following acute emotional stress].

The effect of delta sleep-inducing peptide (DSIP) on the lymphoid structures of small intestine, was investigated. Studies were conducted on 42 male Wistar rats, which were previously assessed in an "open field" test. According to the results of the test, rats were divided into behaviorally active animals (prognostically resistant to stress) and passive ones (resistant to the effects of stress). As a stress, immobilization of the animals in pens with an electrical stimulation of their back for 1 hour, was used. Intraperitoneal injection of DSIP resulted in a reduction of eosinophil number in rats of all the experimental groups. After DSIP injection to the active rats of the control group, the increase in small and medium lymphocyte numbers was detected that was more expressed than in the passive rats. After an acute exposure of behaviorally active rats to stress, the number of the cells of lymphoid series was increased,mainly due to the increase in small and medium lymphocytes. In the group of passive rats, stress exposure and DSIP injection resulted in the increase of plasma cell number in all the duodenal mucosa structures studied.