Pain
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Protein kinase A (PKA) can play a critical role in the modulation of neuronal excitability. We examined the role of PKA in the modulation of abnormal spontaneous activity (SA) originating from the chronically compressed dorsal root ganglion (CCD). The L(4) and L(5) dorsal root ganglia (DRGs) were compressed by inserting a stainless steel rod into each corresponding intervertebral foramen. ⋯ Sp-cAMPS (500 microM), a specific activator of PKA, increased the discharge rate of SA in all injured units tested, but did not trigger firing in silent neurons. Okadaic acid (0.1 microM), a protein phosphatase inhibitor, and forskolin (1 microM), an adenyl cyclase activator, each significantly increased the discharge rate of SA. These results strongly suggest that PKA modulates the SA in injured DRG neurons with myelinated axons.
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This study examined the relationship between pain self-efficacy beliefs and a range of pain behaviours, as measured by the pain behaviour questionnaire (PBQ), using a prospective design. A heterogeneous sample of 145 chronic pain patients completed sets of questionnaires on four occasions over a nine-month period. ⋯ These findings suggest that pain self-efficacy beliefs are an important determinant of pain behaviours and disability associated with pain, over and above the effects of pain, distress and personality variables. In particular, higher pain self-efficacy beliefs are predictive of reduced avoidance behaviours over an extended period.
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Concussion, asphyxia, and systemically administered general anesthetics all induce reversible depression of the organism's response to noxious stimuli as one of the elements of loss of consciousness. This is so even for barbiturate anesthetics, which have only modest analgesic efficacy at subanesthetic doses. Little is known about the neural circuits involved in this form of antinociception, although for anesthetic agents, at least, it is usually presumed that the drugs act in widely distributed regions of the nervous system. ⋯ The behavioral suppression is accompanied by slow-wave EEG and, presumably, loss of consciousness. This zone, which we refer to as the mesopontine tegmental anesthesia locus (MPTA), apparently contains a barbiturate-sensitive 'switch' for both cortical and spinal activity. The very existence of the MPTA locus has implications for an understanding of the neural circuits that control motor functions and pain sensation, and for the cerebral representation of consciousness.
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Randomized Controlled Trial Clinical Trial
Clinical precision of myofascial trigger point location in the trapezius muscle.
Myofascial trigger points (TrPs) have been clinically described as discrete areas of muscle tenderness presenting in taut bands of skeletal muscle. Using well-defined clinical criteria, prior investigations have demonstrated interrater reliability in the diagnosis of TrPs within a given muscle. No reports exist, however, with respect to the precision with which experienced clinicians can determine the anatomic locations of TrPs within a muscle. ⋯ The algometer responses associated with TrP estimates varied inversely with respect to the clinical group's reliability in identify the TrP locations. To summarize, for the trapezius muscle, this study demonstrates that two trained examiners can reliably localize latent TrPs with a precision that essentially approaches the physical dimensions of the clinician's own fingertips. Finally, it should be recognized that the ability to precisely document TrP location appears critical to the success of future studies that may be designed to investigate the etiology and pathogenesis of this commonly diagnosed clinical disorder.
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Most patients with advanced cancer develop diverse symptoms that can limit the efficacy of pain treatment and undermine their quality of life. The present study surveys symptom prevalence, etiology and severity in 593 cancer patients treated by a pain service. Non-opioid analgesics, opioids and adjuvants were administered following the WHO-guidelines for cancer pain relief. ⋯ In conclusion, the high prevalence and severity of many symptoms in far advanced cancer can be reduced, if pain treatment is combined with systematic symptom control. Nevertheless, general, neuropsychiatric and gastrointestinal symptoms are experienced during a major part of treatment time and pain relief was inadequate in 14% of patients. Cancer pain management has to be embedded in a frame of palliative care, taking all the possibilities of symptom management into consideration.