Articles: hyperalgesia.
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Parkinsonism Relat. Disord. · Jan 2017
Abnormal nociceptive processing occurs centrally and not peripherally in pain-free Parkinson disease patients: A study with laser-evoked potentials.
Several studies documented abnormal nociceptive processing in PD patients. Pain central pathways are accessible by laser-evoked potentials (LEPs). LEPs recording show a N2/P2 complex mostly generated by the anterior cingulate cortex, preceded by an earlier negative component (N1), originating from the opercular cortex. Previous work demonstrated N2/P2 amplitude reduction in PD patients and suggested a centrally-acting pathomechanism for the genesis of pain. However, since a peripheral deafferentation has been recently demonstrated in PD, it is not clear if such LEP abnormalities reflect a mechanism acting centrally or not. ⋯ These findings demonstrate that in the PD patients the abnormal processing of pain stimuli occurs at central rather than peripheral level. The co-existence of hyperalgesia and reduced amplitude of the N2/P2 complex, in spite of a normal N1/P1 component, suggests an imbalance between the medial and lateral pain systems. Such a dissociation might explain the genesis of central pain in PD.
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Anesthesia and analgesia · Jan 2017
Randomized Controlled Trial Comparative StudyEffectiveness of Epidural Analgesia, Continuous Surgical Site Analgesia, and Patient-Controlled Analgesic Morphine for Postoperative Pain Management and Hyperalgesia, Rehabilitation, and Health-Related Quality of Life After Open Nephrectomy: A Prospective, Randomized, Controlled Study.
There is no widely recognized effective technique to optimally reduce pain scores and prevent persistent postoperative pain after nephrectomy. We compared continuous surgical site analgesia (CSSA), epidural analgesia (EA), and a control group (patient-controlled analgesic morphine) in patients undergoing open nephrectomy. ⋯ CSSA and EA significantly improve postoperative analgesia, reduce postoperative morphine consumption, area of wound hyperalgesia, and accelerate patient rehabilitation after open nephrectomy. CSSA significantly reduces the severity of residual pain 1 month after surgery and optimizes quality-of-life parameters 3 months after surgery.
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Anesthesia and analgesia · Jan 2017
Comparative StudyChronic Sciatic Neuropathy in Rat Reduces Voluntary Wheel-Running Activity With Concurrent Chronic Mechanical Allodynia.
Animal models of peripheral neuropathy produced by a number of manipulations are assessed for the presence of pathologic pain states such as allodynia. Although stimulus-induced behavioral assays are frequently used and important to examine allodynia (ie, sensitivity to light mechanical touch; von Frey fiber test), other measures of behavior that reflect overall function are not only complementary to stimulus-induced responsive measures, but are also critical to gain a complete understanding of the effects of the pain model on quality of life, a clinically relevant aspect of pain on general function. Voluntary wheel-running activity in rodent models of inflammatory and muscle pain is emerging as a reliable index of general function that extends beyond stimulus-induced behavioral assays. Clinically, reports of increased pain intensity occur at night, a period typically characterized with reduced activity during the diurnal cycle. We therefore examined in rats whether alterations in wheel-running activity were more robust during the inactive phase compared with the active phase of their diurnal cycle in a widely used rodent model of chronic peripheral neuropathic pain, the sciatic nerve chronic constriction injury (CCI) model. ⋯ Compared with nonneuropathic sham controls, a profound and stable reduction of running wheel activity was observed in CCI rats during the inactive phase of the diurnal cycle. A concurrent robust allodynia persisted in all rats regardless of when wheel-running activity was examined or whether they ran on wheels, suggesting that acute wheel-running activity does not alter chronic low-intensity mechanical allodynia as measured using the von Frey fiber test. Overall, these data support that acute wheel-running exercise with limited repeated exposures does not itself alter allodynia and offers a behavioral assay complementary to stimulus-induced measures of neuropathic pain.
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Morphine and other opioids are among the most effective prescription medications for the treatment of pain. Addiction and hyperalgesia associated with their long-term use limits the clinical utility of these drugs. In view of a role of somatodendritic serotonin-1A receptors in addiction and analgesic effects of morphine, the present study concerns effects of co-use of buspirone, a partial agonist at the serotonin-1A receptor, on reinforcing, hyperalgesic, and motor effects of morphine in rats. ⋯ These effects of repeated morphine administration were blocked in rats cotreated with buspirone. Pain perception was also slightly reduced in rats repeatedly treated with higher doses of buspirone. The findings are important for improving and extending therapeutic medications for pain.
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Journal of optometry · Jan 2017
ReviewThe potential role of neuropathic mechanisms in dry eye syndromes.
Dry eye syndromes can involve both nociceptive and neuropathic symptoms. Nociceptive symptoms are the normal physiological responses to noxious stimuli. Neuropathic symptoms are caused by a lesion or disease of the somatosensory nervous system and can be the result of hypersensitisation of peripheral or central corneal and conjunctival somatosensory nerves. ⋯ Dry eye symptoms in the absence of commensurate evidence of tear dysfunction, and unsatisfactory response to tear dysfunction therapies should prompt consideration of neuropathic mechanisms being involved. Symptoms which persist after local anaesthetic instillation are more likely to be neuropathic in origin. Reducing inflammation may help limit any associated neuroplastic hypersensitivity.