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OBJECTIVE Epigenetic mechanisms are potential targets to relieve somatic pain. However, little is known whether epigenetic regulation interferes with visceral pain. Previous studies show that oestrogen facilitates visceral pain. This study aimed to determine whether histone hyperacetylation in the spinal cord could attenuate oestrogen-facilitated visceral(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)
BACKGROUND & AIMS Chronic visceral hyperalgesia is considered an important pathophysiologic symptom in irritable bowel syndrome (IBS); previous gastrointestinal inflammation is a potent etiologic factor for developing IBS. Although there are several animal models of adult visceral hypersensitivity after neonatal perturbation or acute colonic(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)
The present study examined the effect of a spinally administered excitatory amino acid antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; 1, 2.5, 5 microg) on responses of spinal dorsal horn neurons to graded intensities (20, 40, 60, 80 mmHg) of colorectal distention (CRD). Extracellular single unit recordings were made from 28 dorsal horn neurons in(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 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)
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)
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)
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)