Yaping Ji

Learn More
Increasing evidence suggests there is a sex difference in opioid analgesia of pain arising from somatic tissue. However, the existence of a sex difference in visceral pain and opioid analgesia is unclear. This was examined in the colorectal distention (CRD) model of visceral pain in the current study. The visceromotor response (vmr) to noxious CRD was(More)
UNLABELLED We have recently reported a sex difference in morphine-induced analgesia in a visceral pain model. To test the hypothesis that estrogen plays a role in mediating this sex difference, the effect of morphine on the visceromotor response (vmr) to colorectal distention was compared between ovariectomized (OVx) and OVx with estrogen replacement (E2)(More)
Pain symptoms in several chronic pain disorders in women, including irritable bowel syndrome, fluctuate with the menstrual cycle suggesting a gonadal hormone component. In female rats, estrogens modulate visceral sensitivity although the underlying mechanism(s) are unknown. In the present study the effects of 17-beta estradiol on N-methyl-D-aspartate (NMDA)(More)
Many gastrointestinal pain syndromes are more prevalent in women than men, suggesting a gonadal steroid influence. We characterized the effects of estrogen on two responses to colorectal distention (CRD) in the rat: the visceromotor reflex (vmr) and L6-S1 dorsal horn neuron activity (ABRUPT and SUSTAINED neurons). Ovariectomized rats were injected with(More)
We previously reported that 17β-estradiol (E2) is pronociceptive in a visceral pain model in the rat. Subcutaneously (s.c.) administered E2 reversed the decrease in the colorectal distention (CRD)-evoked visceromotor response produced by ovariectomy (OVx) and CRD-induced nociceptive responses were greater in proestrous rats compared with met/diestrous rats.(More)
UNLABELLED The mechanism underlying estrogen modulation of visceral pain remains unclear. Our previous studies indicate that activation of estrogen receptor α (ERα) enhances visceral pain. The purpose of the present study was to investigate the role of estrogen receptor β (ERβ) activation in spinal processing of visceral stimuli. The effects of selective(More)
UNLABELLED Tissue damage during the first few weeks after birth can have profound effects on sensory processing in the adult. We have recently reported that a short-lasting inflammation of the neonatal rat hind paw produces baseline hypoalgesia and exacerbated hyperalgesia after reinflammation of that hind paw in the adult. Because the contralateral hind(More)
The contribution of estrogen and progesterone to colorectal hyperalgesia was examined in female rats. The electromyogram recorded from the abdominal wall (visceromotor response, vmr) and the discharge of lumbosacral dorsal horn neurons to colorectal distention (CRD) were measured in intact female, ovariectomized (OVx) and estradiol replaced OVx (E2; 50mug,(More)
Women disproportionately suffer from many deep tissue pain conditions. Experimental studies show that women have lower pain thresholds, higher pain ratings and less tolerance to a range of painful stimuli. Most clinical and epidemiological reports suggest female gonadal hormones modulate pain for some, but not all, conditions. Similarly, animal studies(More)
Sex differences in the spinal processing of somatic and visceral stimuli contribute to greater female sensitivity in many pain disorders. The present study examined spinal mechanisms that contribute to sex differences in visceral sensitivity. The visceromotor response to colorectal distention (CRD) was more robust in normal female rats and after(More)