Pain Syndrome In Women Research Articles

Activation of α 2-adrenoceptors in the trigeminal region produces sex-specific modulation of nociception in the rat

Sex-related differences in the sensitivity to pain and in the response to analgesics have been reported including higher perceptual responses to experimentally induced pain and the higher prevalence of many pain syndromes in women compared with men. This study examines whether α 2-adrenoceptor-mediated antinociceptive effects are reduced by estrogen which could account for the sex-related differences in pain perception and modulation. Clonidine, an α 2-adrenoceptor agonist, has been shown to inhibit noxious stimulus-evoked nociceptive behavior as well as the responses of nociceptive neurons in the medullary dorsal horn. Intracisternal microinjection of clonidine (7 μg/5 μl) through the implanted PE-10 cannulae dorsal to the trigeminal region in male, ovariectomized (OVX), and diestrous (DiE) Sprague–Dawley rats produced a strong antinociceptive effect on N-methyl- d-aspartic acid (NMDA)-induced nociceptive scratching behavior and heat-induced face withdrawal nociceptive tests. However, it failed to produce any inhibition in the estradiol-treated ovariectomized (OVX+E) group regardless of the dose of estradiol (1, 10 or 100 μg/100 μl sesame oil) or in the proestrous (ProE) group. Further, clonidine produced dose-dependent effects in male and OVX groups but not in the OVX+E group on the NMDA-induced nociceptive behavior. Finally, the effect of clonidine was reversed by yohimbine, an α 2-adrenoceptor antagonist, in male and OVX groups on thermal nociceptive test. These results lead us to conclude that activation of α 2-adrenoceptors produces sex-specific, estrogen dependent modulation of nociception in the trigeminal region of the rat. A decreased α 2-adrenoceptor-mediated inhibition could be one of the factors responsible for the higher prevalence of pain syndromes in females.

Dysménorrhées

Dysmenorrhoea, the most burdensome chronic pain syndrome in women, results in frequent absences from school or work, which translate into major social and economic costs. Primary essential dysmenorrhoea requires neither a physical examination nor other investigations. Secondary dysmenorrhoea is often caused by endometriosis. The mechanism underlying dysmenorrhoea is tissue hypoxia secondary to myometrial hypercontractility and to myometrial arteriolar constriction in response to endometrial overproduction of prostaglandins. Monthly pain should no longer be considered inevitable, as effective treatment is now available. The main drug classes used to treat dysmenorrhoea are nonsteroidal antiinflammatory drugs and oral contraceptives, both of which inhibit prostaglandin production.

Gonadal hormones and sex differences in pain reactivity.

Sex differences in the response threshold to painful stimuli and the higher number of chronic pain syndromes in women than in men have prompted a series of studies on lower animals and humans aimed at clarifying the role of gonadal hormones in pain. This article examines the morphologic and functional aspects of gonadal hormone systems and the relations between gonadal hormones and pain circuits, to identify areas deserving of increased attention in elucidating the endocrine mechanisms that contribute to abnormal pain states.

Rasch analysis of Visual Analog Scale measurements before and after treatment of Patellofemoral Pain Syndrome in women

The Visual Analog Scale (VAS) can be used to record subjectively experienced pain in different situations (items). By a mathematical method, the Rasch analysis, the original VAS recordings can be converted to an interval scale. Forty women with Patellofemoral Pain Syndrome (PFPS) reported their pain on the VAS from 12 different situations (items) before and after 12 weeks of rehabilitation. The items recorded pain during the last 3 months, during provocation tests, and during activities such as walking up stairs, jumping and strength testing. It was concluded that the items used for the patients with PFPS were hierarchically ordered in a statistically equivalent manner before and after rehabilitation. Subjectively reported pain after 12 weeks of rehabilitation was significantly alleviated for 23 (58%) of the 40 patients, compared with before rehabilitation. The patients with PFPS did not use the VAS as a linear scale over the full range. Rasch analysis of recordings made with the VAS gave a more detailed pain assessment.