Uterine inflammation as a noxious visceral stimulus: behavioral characterization in the rat.

We have developed a model of uterine inflammation in the rat. The purpose of this study was to characterize the behavioral manifestations of uterine pain. Mustard oil was injected into one uterine horn to produce chemical inflammation. Control rats were sham-operated. Non-stop videotape recording was performed for 7 days to monitor rat behavior. Rats with uterine inflammation showed abnormal behavior during the first 4 days (hunching, hump-backed position, licking of the lower abdomen, repeated waves of contraction of the ipsilateral oblique musculature with inward turning of the ipsilateral hindlimb, stretching, squashing of the lower abdomen against the floor) suggestive of visceral pain and evidence of flank muscle hyperalgesia over 7 days indicative of referred visceral pain. This model resembles closely a state of inflammatory uterine pain and will allow to gain further insight into the neural processes which contribute to visceral nociception.