Articles: hyperalgesia.
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Randomized Controlled Trial
Mechanisms of adrenosensitivity in capsaicin induced hyperalgesia.
It is well known that iontophoresis of norepinephrine in capsaicin treated skin is followed by an increase in thermal hyperalgesia. It is unclear if this action on nocicepitive afferents involves the release of prostaglandins. The aim of the present study was to determine: (1) the effect of norepinephrine iontophoresis on spontaneous and evoked pain in the human skin after topical application of capsaicin; (2) the effect of cyclooxygenase (COX) inhibition on changes in pain perception induced by norepinephrine application. ⋯ The results do not support the assumption that in human skin sensitized by topical capsaicin application of norepinephrine acts on nociceptive afferents via the release of prostaglandins. Thus, a direct action of norepinephrine on adrenergic receptors in the membrane of the afferent fibers is most likely.
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Objective. Development of a spinal cord stimulation (SCS) system in a mouse model of chronic neuropathic pain. Materials and Methods. Male C57BL/6 mice (N = 6) underwent a partial ligation of the sciatic nerve. Development of mechanical hyperalgesia was tested using the withdrawal response to tactile stimuli with the von Frey test. ⋯ After termination of the SCS, the withdrawal threshold of the ipsilateral paw slowly decreased. No effect of SCS on the contralateral paw was noted. Conclusion. The development of a mouse SCS system is described that is practical in use, is reproducible, and shows a comparative therapeutic effect in treatment of chronic neuropathic pain as reported in rat.
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Nocebo hyperalgesia is a phenomenon that is opposite to placebo analgesia and whereby expectation of pain increase plays a crucial role. In recent times, both the neuroanatomical and the neurochemical bases of the nocebo effect and of nocebo-related effects have begun to be explored. Here, we highlight recent advances in our understanding of the neurobiology of the nocebo hyperalgesic effect. ⋯ Since pain appears to be amplified by anxiety through the activation of cholecystokininergic systems, new therapeutic strategies, such as new cholecystokinin antagonists, can be envisaged whenever pain has an important anxiety component.
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Long-term consequences of early infant injury upon somatosensory processing were tested in school aged children. The aim was to test whether the long-term changes in sensitivity reported in animal models, in regions both local to and distant from the injury site, could be observed in humans. To do this we used quantitative sensory testing (QST) in children aged 9-12 years who had undergone cardiac surgery in infancy. ⋯ Questionnaires revealed perceived differences in pain perception, individual aberrant sensations and pain interfering with daily life that warrant further study. We conclude that tissue injured in early infancy remains measurably altered to mechanical and thermal stimulation in later life. These findings are consistent with the results of animal studies that early infant injury has not only local, but also global long-term consequences upon sensory processing.
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J Pain Symptom Manage · Oct 2007
Clinical TrialManaging the symptoms of neuropathic pain: an exploration of patients' experiences.
The debilitating effects of chronic neuropathic pain on everyday life are considerable, but little is known about how individual sufferers manage these effects. Virtually nothing is known about what patients prefer, what measures they take themselves and when, or in what combinations. The aim of this study was to explore patients' reports of how they managed their neuropathic pain symptoms. ⋯ Some had tried to accept their pain, but there was insufficient psychological, social, emotional, and practical support to allow them to do this successfully. This exploratory study provides a basis from which to develop a larger study to validate and extend the findings. Other issues meriting research are the effectiveness of cognitive-behavioral therapies for those with neuropathic pain, and an exploration and subsequent evaluation of different types of social, practical, and emotional support needed to help live with neuropathic pain.