European journal of pain : EJP
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Cardiovascular risk factors in cognitively impaired nursing home patients: a relationship with pain?
Cardiovascular risk factors (CRF) such as hypertension and diabetes mellitus favour the development of both vascular dementia (VaD) and Alzheimer's disease (AD). The resulting deafferentation may increase the experience of pain in VaD and in AD. ⋯ In a multivariate logistic regression model (adjusted for gender, age and depression) the presence of diabetes or hypertension was a risk indicator for pain: odds ratio: 3.48, p=0.005, 95% CI: 1.45-8.38. This finding supports the hypothesis that as a result of CRF, disruptions of cortico-cortico and cortico-subcortical pathways occur, and consequently, enhances pain in this group of patients.
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Neuropathic (NP) pain is a debilitating chronic pain disorder considered by some to be inherently resistant to therapy with traditional analgesics. Indeed, micro opioid receptor (OR) agonists show reduced therapeutic benefit and their long term use is hindered by the high incidence of adverse effects. However, pharmacological and physiological evidence increasingly suggests a role for deltaOR agonists in modulating NP pain symptoms. ⋯ The effects of deltorphin II were mediated via activation of the deltaOR as the effect was antagonized by co-treatment with the delta-selective antagonist, naltrindole. Western blotting experiments revealed no changes in deltaOR protein in the dorsal spinal cord following CCI. Taken together, these data demonstrate the antihyperalgesic and antiallodynic effectiveness of a spinally administered deltaOR agonist following peripheral nerve injury and support further investigation of deltaORs as potential therapeutic targets in the treatment of NP pain.
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This study used the metabotropic glutamate 5 (mGlu5) receptor subtype-selective antagonist 2-methyl-6-(phenylethynyl)pyridine (MPEP) to characterise the contribution of mGlu5 receptor activity to pain and hypersensitivity in an animal model of post-surgical pain. Adult female Wistar rats (200-250g) were anaesthetised with isoflurane (2%) and underwent a midline laparotomy with gentle manipulation of the viscera, and the effects of pre- (30min) or post- (5h) operative treatment with MPEP (1, 3 or 10mgkg(-1); i.p.) or drug-vehicle on hindpaw withdrawal latency (in seconds) to thermal stimulation (Hargreave's Test) and response threshold (in grams) to mechanical stimulation (using a dynamic plantar aesthesiometer) were measured. Animals that underwent surgery displayed significant hypersensitivity to mechanical stimulation of the hindpaws. ⋯ Both pre-operative and post-operative administration of 10mgkg(-1)MPEP blocked mechanical hypersensitivity induced by surgery (p<0.01 vs. vehicle treatment). MPEP had no effect on acute nociceptive thresholds in naïve animals. These data suggest that activity at mGlu5 receptors contributes to development of pain and hypersensitivity following surgery.
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Complex regional pain syndromes (CRPS) are disabling pain syndromes that can develop after trauma or minor tissue injury affecting a limb. Characteristics of CRPS are sensory signs and symptoms, autonomic abnormalities, trophic changes and an impaired motor function. Pathophysiological mechanisms for the development of CRPS are still a matter of investigation. ⋯ Both in rats that underwent ischemia and in sham-operated rats no obvious changes of hindpaw tissue were observed after ischemia-reperfusion injury (trophic changes, edema, differences in skin color or temperature). In behavioral tests only minor changes were observed, these being not different between postischemic rats and sham-operated rats. Using Wistar rats, our data do not support the idea that an ischemia-reperfusion injury can play a major role in the development of CRPS.
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Botulinum toxin injection is used to treat various pain conditions including muscle spasticity, dystonia, headache and myofascial pain. Results are conflicting regarding the use of Botulinum toxin for trigger point injection in terms of improvement in pain. The aim of this study was to carry out a systematic review to assess the evidence for efficacy of Botulinum toxin A (BTA) compared with placebo for myofascial trigger point injection. ⋯ OPVS scores ranged from 8 to 14 with the negative studies corresponding with higher validity scores. The current evidence does not support the use of BTA injection in trigger points for myofascial pain. The data is limited and clinically heterogeneous.