Articles: hyperalgesia.
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Neuroscience research · May 2007
FK506 reduces the severity of cutaneous hypersensitivity in rats with a spinal cord contusion.
Spinal cord injury (SCI) leads to persistent pain as well as motor dysfunction, both of which lack effective therapeutics. The immunosuppressant FK506 (tacrolimus) has been shown to improve behavioral outcome following SCI in rats. Just prior to a mid-thoracic spinal cord contusion injury, rats were injected with either vehicle or FK506 and treatment was continued through the duration of the experiment. ⋯ Neither treated groups demonstrated an improvement in locomotor function. Thus, some SCI-induced pain is mediated by an FK506-sensitive mechanism. The data also suggest that motor and sensory dysfunctions resulting from SCI are mediated by distinct mechanisms, requiring the use of multiple therapeutic interventions.
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Neck and shoulder pain is a common disorder which is often associated with a low-pressure pain threshold (PPT) of muscle tissues as manifested by hyperalgesia on palpation or the use of a pressure algometer. The objective of the present study was to evaluate the intratester repeatability of pressure algometer (Force-Five) on the neck and shoulder area in women with neck pain. The study was cross-sectional with single-group repeated measurements. ⋯ Considerable individual variation was observed when consecutive measures were analysed against their mean. On the group level the repeatability of the measurements allows the pressure algometer to be used for research purposes. However, on the individual level, due to the considerable variation found in the PPT results, caution is advised when interpreting the results in clinical practice.
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Some chronic painful conditions including e.g. fibromyalgia, whiplash associated disorders, endometriosis, and irritable bowel syndrome are associated with generalized musculoskeletal hyperalgesia. The aim of the present study was to determine whether generalized deep-tissue hyperalgesia could be demonstrated in a group of patients with chronic low-back pain with intervertebral disc herniation. Twelve patients with MRI confirmed lumbar intervertebral disc herniation and 12 age and sex matched controls were included. ⋯ The patients rated significantly higher pain intensity to supra-threshold mechanical pressure stimulation in both muscles. In patients, the pressure pain-threshold was lower in the anterior tibialis muscle compared to controls. In conclusion, generalized deep-tissue hyperalgesia was demonstrated in chronic low-back pain patients with radiating pain and MRI confirmed intervertebral disc herniation, suggesting that this central sensitization should also be addressed in the pain management regimes.
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The aim of this study was to differentiate the processing of nociceptive information, matched for pain intensity, from capsaicin-induced hyperalgesic vs. control skin at multiple levels in the trigeminal nociceptive pathway. Using an event-related fMRI approach, 12 male subjects underwent three functional scans beginning 1 h after topical application of capsaicin to a defined location on the maxillary skin, when pain from capsaicin application had completely subsided. Brush and two levels of painful heat (low-Thermal-1 and high-Thermal-2) were applied to the site of capsaicin application and to the mirror image region on the opposite side. ⋯ Thus, trigeminal nociceptive regions showed increased activation in the context of perceptually equal pain levels. Beyond these regions, contrast analyses of capsaicin vs. control skin stimulation indicated significant changes in bilateral dorsolateral prefrontal cortex and amygdala. The involvement of these emotion-related regions suggests that they may be highly sensitive to context, such as prior experience (application of capsaicin) and the specific pain mechanism (hyperalgesic vs. normal skin).