Electrophysiological study on the modulation of uterine mechanoreceptor by substance P / 대한산부인과학회잡지

OBJECTIVE: In inflammation, hyperalgesia is a common phenomenon but its mechanism has not been clarified. Recently some reports suggested substance P might be important factors for inflammatory hyperalgesia in somatic tissue. This study was performed to see whether substance P modulate the activities of uterine afferent fibers in the hypogastric nerve of the cat. METHODS: While recording the electrical activities of nerve fibers, mechanical stimuli were applied as balloon distention using balloon inserted into uterine lumen before and during substance P infusion through uterine artery. RESULTS: Substance P increased the responses to balloon distension of uterus in 14 uterine mechanoreceptive afferent fibers of 24 over 10% compared to before substance P infusion, and decreased the responses of 3. And L-703,606, the neurokinin 1 receptor antagonist failed the modulation of mechano sensitive response by substance P and reduced the spontaneous activities. CONCLUSIONS: These results suggest that substance P modulated the activities of uterine nerve fibers and their responses to mechanical stimulus. It is hypothesized that this kind of modulation of afferent nerve fibers by substance P may be important for the development of inflammatory hyperalgesia.

Alterations in substance P and CGRP immunoreactivities in the uterus following the induction of inflammation in the rats / 대한산부인과학회잡지

OBJECTIVE: Recently some reports suggested substance P and CGRP might be important factors for inflammation and hyperalgesia. This study was performed to see whether substance P or CGRP containing nerve fibers might be changed by mustard oil-induced inflammation. METHODS: After injection of mustard oil(5%) into uterine lumen, the uteri were removed and examined with immunohistochemical methods for substance P and CGRP. RESULTS: In the normal uterus, most of the substance P- or CGRP-immunoreactive nerve fibers were observed along the vascular structure and some in the myometrium, only few in the endometrium. Mustard oil did not changed this pattern of nerve fiber distribution but after 48 hrs, the amount of substance P or CGRP immunoreactive nerve fibers were greatly reduced compared with the normal uterus. It is not clear whether the decrease of substance P and CGRP immunoreactive fibers in the uterus was resulted from the depletion of the neuropeptides in the nerve fibers or the retraction of nerve fibers. CONCLUSIONS: These results suggest that the inflammation should cause the change of nerve fibers included in the nociception. This change may attribute the generation of inflammation and inflammatory hyperalgesia.