The Effects of Myometritis on the Sensory Receptors in the Feline Uterus

Lee, N W; Lee, M G; Han, H C; Hong, S K; Rha, J Y

Abstract

OBJECTIVE
To examine whether the inflammation can alter the sensitivity of primary afferents innervating uterus and its adjacent tissues, and to elucidate the role of substance P which are known to be released to the inflamed tissues.
METHODS
Total fourteen female cats were used, four cats were used for inflammation tests. Uterine inflammation was induced by 10% of mustard oil after papain [3mg/ml] treatment. These chemicals were injected into the uterine cavity. Other 10 cats were used for substance P [5 g] tests which was injected into the uterine circulation. The responses of hypogastric nerve to bradykinin injected into the uterine circulation were recorded before and after either treatments [inflammation or substance P] using electrophysiological method.
RESULTS
The neuronal responses to bradykinin were increased at 2 hours and 4 hours after uterine inflammation. As for substance P treatment, the responses of 8 of 11 thin myelinated [A ] nerve fibers were decreased after substance P treatment, those of all 10 of unmyelinated [C] nerve fibers were increased.
CONCLUSIONS
These results indicated that the afferents from the uterus responded to bradykinin more sensitively after inflammation and substance P which are released after inflammation may play a important role in uterine hyperalgesia.