Cell-to-cell communications are desirable for efficient functioning in endocrine cells. Gap junctions and paracrine factors are major mechanisms by which neighboring endocrine cells communicate with each other. The current experiment was undertaken to morphologically examine gap junction expression and developmental changes in rat adrenal medullary chromaffin (AMC) cells. The expression of connexin 43 (Cx43) was conspicuous in the rat adrenal cortex, but not detected immunohistochemically in neonatal or adult AMC cells. Consistent with the morphological findings, the phosphorylated and non-phosphorylated forms of Cx43 were predominantly and faintly detected by immunoblotting in the adrenal cortical and medullary homogenates, respectively. In contrast to Cx43, Cx36-like immunoreactive (IR) material was detected in neonatal AMC cells, a fraction of which were in the process of migration to the center of the adrenal gland, but this was not seen in adult AMC cells. The current results raise the possibility that the mechanism for cell-to-cell communication changes in a developmental manner in rat AMC cells.

Inflammatory bowel disease is triggered by abnormalities in epithelial barrier function and immunological responses, although its pathogenesis is poorly understood. The dextran sodium sulphate (DSS)-induced colitis model has been used to examine inflammation in the colon. Damage to mucosa primality occurs in the large intestine and scarcely in the small intestine. To evaluate the effect on the ileum, we histologically analyzed the inflammatory and recovery phases in DSS model mice, and 40 kDa FITC-dextran was used to investigate barrier function. In the inflammatory phase, histological damage was insignificant. However, expanded crypts, hypertrophic goblet and Paneth cells, increased mucus production and secretion were observed. The cellular morphology was restored to that of the control in the recovery phase. According to in situ hybridization and lectin histochemistry, the expression of intestinal stem cell markers, secretory cell differentiation factors, and glycosylation of secretory granules in Paneth cells differed in the DSS model. DSS-treatment did not influence the barrier function in the ileum, and FITC-dextran did not diffuse via the paracellular pathway into the mucosa. However, cells incorporating FITC appeared even under normal conditions. The number of FITC-positive Paneth cells was lower in the DSS group than the control group. Our results showed morphological and functional alterations in ileal epithelial cells, especially secretory cells, in the DSS colitis model.