Articles: hyperalgesia.
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A prospective, randomized experimental research. ⋯ N/A.
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Arthritis Rheumatol · Sep 2014
Contribution of transient receptor potential ankyrin 1 to chronic pain in aged mice with complete Freund's adjuvant-induced arthritis.
To investigate age-related differences in mechanical sensitivity to inflammatory pain and determine the contribution of transient receptor potential ankyrin 1 (TRPA1) to mechanical hypersensitivity during chronic inflammation in young and aged mice with complete Freund's adjuvant (CFA)-induced arthritis. ⋯ These findings reveal marked differences in the long-term mechanical behavioral sensitivity of aged and young mice, and suggest that TRPA1 may be a key contributor to the transition from acute to chronic inflammatory pain in response to mechanical stimuli as well as to the development of nociceptor sensitization selectively in aged mice.
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Low vitamin D is implicated in various chronic pain conditions with, however, inconclusive findings. Vitamin D might play an important role in mechanisms being involved in central processing of evoked pain stimuli but less so for spontaneous clinical pain. ⋯ The findings suggest a role of low vitamin D levels for heightened central sensitivity, particularly augmented pain processing upon mechanical stimulation in chronic pain patients. Vitamin D seems comparably less important for self-reports of spontaneous chronic pain.
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Although transcutaneous electrical nerve stimulation (TENS) is widely used for the treatment of neuropathic pain, its effectiveness and mechanism of action in reducing neuropathic pain remain uncertain. We investigated the effects of early TENS (starting from the day after surgery) in mice with neuropathic pain, on hyperalgesia, glial cell activation, pain transmission neuron sensitization, expression of proinflammatory cytokines, and opioid receptors in the spinal dorsal horn. Following nerve injury, TENS and behavioral tests were performed every day. ⋯ Early TENS decreased p-p38 within microglia (P<0.05), the expression levels of protein kinase C (PKC-γ), and phosphorylated anti-phospho-cyclic AMP response element-binding protein (p-CREB) in the superficial spinal dorsal horn neurons (P<0.05), mitogen-activated protein (MAP) kinases, and proinflammatory cytokines, and increased the expression levels of opioid receptors (P<0.05). The results suggested that the application of early TENS relieved hyperalgesia in our mouse model of neuropathic pain by inhibiting glial activation, MAP kinase activation, PKC-γ, and p-CREB expression, and proinflammatory cytokines expression, as well as maintenance of spinal opioid receptors. The findings indicate that TENS treatment is more effective when applied as early after nerve injury as possible.