Electrophysiological study on the modulation of uterine  mechanoreceptor by substance P.

Na, Joong Yol; Chang, Ki Hoon; Shin, Jae Chul; You, Sang Wook; Hong, Soon Choul; Lee, Seo Eun; Han, Hee Chul

Original Article

Korean Journal of Obstetrics & Gynecology 2001;44(4):740-747.
Published online April 1, 2001.

Electrophysiological study on the modulation of uterine mechanoreceptor by substance P.

Joong Yol Na, Ki Hoon Chang, Jae Chul Shin, Sang Wook You, Soon Choul Hong, Seo Eun Lee, Hee Chul Han

¹Department of Obstetrics and Gynecology, College of Medicine, Korea University, Seoul, Korea.
²Department of Physiology, College of Medicine, Korea University, Seoul, Korea.

Abstract

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.

Key Words: Substance P, Inflammatory hyperalgesia, Uterine nerve fiber