Pain
-
Features of somatisation have been shown to predict the onset of widespread body pain. This study aims to determine to what extent persons with orofacial pain syndromes share these features and to what extent they are uniquely related to oral mechanical factors. We have conducted a population-based cross-sectional survey in the South-East Cheshire area of the United Kingdom involving 2504 individuals aged 18-65 years. ⋯ Several oral mechanical factors were significantly associated with both orofacial pain and widespread body pain (grinding teeth, clicking jaw, missing teeth), while two (facial trauma, locking jaw) were specifically related to orofacial pain. Both pain syndromes were associated equally with high levels of psychological distress, indicators of somatisation and maladaptive response to illness. These results suggest that orofacial pain syndromes may commonly be a manifestation of the process of somatisation and the excess reporting of some local mechanical factors amongst persons with these symptoms, may not be uniquely associated with pain in the orofacial region.
-
Plasticity in the spinal dorsal horn may underlie the development of chronic pain following peripheral nerve injury or inflammation. In this study, we examined whether chronic constriction injury of the sciatic nerve was associated with changes in the immunoreactive content of cyclic AMP response element binding protein (CREB), protein kinase A (PKA), and calcineurin Aalpha and Abeta in the spinal dorsal horn. In animals exhibiting thermal hyperalgesia as a behavioral sign of neuropathic pain 7 days after loose ligation of the sciatic nerve (chronic constriction injury), there was a significant increase in the content of phosphorylated (activated) CREB (pCREB). ⋯ In contrast, there were no differences in the content of non-phosphorylated CREB, and phosphorylated or non-phosphorylated PKA between control and sciatic ligation animals either 7 or 28 days after surgery. These data established a close association in the expression of thermal hyperalgesia with CREB activation and decreased calcineurin content in the spinal dorsal horn. The data revealed a significant but reversible shift in the manner in which spinal neurons processed sensory information following peripheral nerve injury, and lent further support to the notion that plasticity in the spinal dorsal horn may have contributed to the development of chronic pain.
-
This study was designed to determine whether intrathecal octreotide (sandostatin), a synthetic octapeptide derivative of somatostatin, relieved thermal hyperalgesia and reduced the evoked spinal c-Fos expression in rats with chronic constriction injury (CCI) of the sciatic nerve. Intrathecal catheters were implanted in rats 7 days before CCI of the sciatic nerve over the left hind limb. After confirmation of the development of thermal hyperalgesia by decreased paw withdrawal latencies (PWL) to heat stimulation 7 days after CCI, intrathecal sandostatin at 20, 40, and 80 microg was administered, respectively. ⋯ Expression of Fos-LI neurons in the 80 microg group was nearly completely inhibited. These data suggest that intrathecal sandostatin significantly relieved thermal hyperalgesia behaviorally but with limited effects and dose-dependently reduced spinal Fos-LI neurons expression evoked by stroking stimulation, which may reflect mechanical allodynia in rats with sciatic constriction injury. This implies that intrathecal sandostatin was effective in the treatment of neuropathic pain.