Articles: hyperalgesia.
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Dopamine is implicated in different orofacial pain-related diseases. The mechanisms underlying this invalidating pain are not yet understood. Therefore, the present study investigated if unilateral or bilateral lesions of the medial forebrain bundle (MFB) could induce a trigeminal static mechanical allodynia (SMA) comparable to that obtained after chronic construction injury of the infraorbital nerve (CCI-IoN) in rats. ⋯ Our data show that unilateral and bilateral dopamine depletion promoted trigeminal SMA comparable to that obtained after CCI-IoN. This allodynia can be alleviated by D2R activation, making D2R agonist a potential analgesic for orofacial neuropathic pain.
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Anesthesia and analgesia · Feb 2016
Regulation of the NR2B-CREB-CRTC1 Signaling Pathway Contributes to Circadian Pain in Murine Model of Chronic Constriction Injury.
Numerous clinical investigations have revealed the circadian rhythm changes in the perception of chronic pain, and most clinical chronic pain types peak in the night. However, it is still undiscovered whether circadian rhythm of pain exists in rodents and the specific mechanism that may underlie it. Our study was conducted to investigate the rhythmic changes of hyperalgesia behavior in a chronic constrictive injury (CCI) model of rodents and to explore the role of the N-methyl-d-aspartate receptor 2B (NR2B)-cAMP response element binding protein (CREB)-CREB-regulated transcription coactivator 1 (CRTC1) signaling pathway in this pain rhythm. ⋯ Pain behavior in the chronic pain of CCI displayed circadian rhythm and was associated with circadian secretion of pain-related receptors. The NR2B-CREB-CRTC1 signaling pathway may play a crucial role in this rhythm. Moreover, our results suggest that measures to relieve pain should be taken before pain reaches its peak.
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Observational Study
Differential Postoperative Effects of Volatile Anesthesia and Intraoperative Remifentanil Infusion in 7511 Thyroidectomy Patients: A Propensity Score Matching Analysis.
Although remifentanil is used widely by many clinicians during general anesthesia, there are recent evidences of opioid-induced hyperalgesia as an adverse effect. This study aimed to determine if intraoperative remifentanil infusion caused increased pain during the postoperative period in patients who underwent a thyroidectomy. A total of 7511 patients aged ≥ 20 years, who underwent thyroidectomy between January 2009 and December 2013 at the Asan Medical Center were retrospectively analyzed. ⋯ However, the incidence of itching was higher in group R (4.3%) than in group N (0.7%) (P < 0.001). Continuous infusion of remifentanil during general anesthesia can cause higher intensity of postoperative pain and more frequent itching than general anesthesia without remifentanil infusion immediately after thyroidectomy. Considering the advantages and disadvantages of continuous remifentanil infusion, volatile anesthesia without opioid may be a good choice for minor surgeries, such as thyroidectomy.
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Disturbed endogenous pain modulation is likely one of the mechanisms underlying central hypersensitivity and might be a contributing factor for the development and maintenance of chronic pain. To our knowledge, no study has investigated endogenous pain modulation in both acute and chronic low back pain (LBP). We tested the hypothesis that endogenous pain inhibition is impaired in patients with acute and chronic LBP. ⋯ The present study provides evidence for some alterations of endogenous modulation in both acute and chronic LBP. CPM was still detected in both patient groups, indicating that endogenous modulation, although effective for a shorter duration, is partially functioning in patients with LBP.