The Variabilities of the Neurotransmitter Responses upon Capsaicin on theMyenteic Plexus of the Rat Small Intestine

To investigate the capsaicin effects on the enteric nervous system, capsaicin was administered to the neonatal and the adult rats and morphometric, immunohistochemical and electron microscopic studies have been done. Capsaicin (50㎎/kg) was injected subcutaneously in the 2nd and 4th day after birth and to the adult rats, same amount was injected once subcutaneously. Experiment was performed 5, 10, 20, 30 days and 10 weeks after injection in the neonatal rats and 1 week after injection in the adult rats. In the immunohistochemical study, the immunoreactivities of various neurotransmitters were compared and arrangement of enteric plexus was also compared. The immunoreactivities against calcitonin gene-related peptide (CGRP), substance P (SP) and somatostatin (SOM) were decreased significantly, while the immunoreactivities against vasoactive intestinal polypeptide (VIP) and met-enkephalin were not changed much. With these changes, capsaicin decrease the immunoreactivities against CGRP, SP and SOM. It could be assumed that capsaicin influence the intestinal motility.ope