Résumé
OBJECTIVE: To find out wheather the substance P takes part in the pain mediating system of uterus, and to ascertain the role of substance P in the hypersensitivity of hypogastric nerve to bradykinin during the uterine inflammation. METHODS: The uterus has two sensory innervations, which are the hypogastric nerve and the pelvic nerve. Since the hypogastric nerve is known to show increased sensitivity to bradykinin, a pain mediator, when the uterus is in inflammatory state, the hypogastric nerve recording was done for electrophysiological study of uterine pain-mediating mechanism in female SD rats (200-250 g). NK1 receptor antagonist (L-703,606) was injected through uterine artery before injecting bradykinin while uterus was under inflammation. RESULTS: The NK-1 receptor antagonist (L-703,606) decreased the spontaneous nerve impulse during inflammation, and it also decreased the hypersensitivity of the hypogastric nerve to bradykinin during the uterine inflammation. CONCLUSION: Substance P mediates the pain sense of hypogastric nerve, and it also plays a role in increased sensitivity of hypogastric nerve to bradykinin while uterus is in inflammatory state.