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in rats. On the other hand, Bradesi et al.14) used water-avoidance stress. Furthermore, restraint stress has been used in rat stress models. The number of defecations in rats reportedly increase Figure 4　Enterochromaffin cell (EC cell) expression tended to increase in the restraint group compared to that in the control group in both the small intestine and colon. Bar = 100 μm. A: Photographs of the small intestine tissue. The positive cells (EC cells) were detected. The number of positive cells between the restraint and control groups was compared. B: Photographs of the colon tissue. The number of positive cells between the restraint and control groups was compared.Figure 5　Comparison of the number of positive cells in the restraint (n = 6) and control (n = 6) groups and expression of 5-Hydroxytryptamine (5-HT) in the small intestine and colon. 5-HT is secreted from EC cells. EC cells that were stained and positive were counted. The number of EC cells in the small intestine increased in the restraint group, but not in the colon. A: The counted positive cells in the colon were compared between the restraint and control groups. B: The counted positive cells in the small intestine were compared between the restraint and control groups.by restraining the body6). In the present study, adolescent rats subjected to restraint alone at room temperature showed an increase in the fecal pellet output without the formation of gastrointestinal 277