Pain
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Randomized Controlled Trial Clinical Trial
Effects of low-power laser exposure on masseter muscle pain and microcirculation.
One possible cause of the reported positive treatment effect by low-power laser exposure in muscle pain conditions could be that it increases the local microcirculation. The aim of this study was therefore to investigate the immediate effects on masseter muscle blood flow by low-power laser exposure in patients with chronic orofacial pain of muscular origin in comparison to healthy individuals. Twelve patients with myofascial pain of orofacial muscles and 12 age and gender matched healthy individuals participated in the study. ⋯ The blood flow did not change significantly in the patients, but increased after active laser exposure and decreased after placebo exposure in the healthy individuals. The difference between active laser and placebo was significant. In conclusion, the results of this study do not support an effect of low-power laser exposure on masseter muscle microcirculation in patients with chronic orofacial pain of muscular origin.
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In the past decade, our knowledge of pain in newborn infants has advanced considerably. However, infants at significant risk for neurologic impairment (NI) have been systematically excluded from almost all research on pain in neonates. The objectives of this study were to compare: (a). the nature, frequency and prevalence of painful procedures, (b). analgesics and sedatives administered, and (c). the relationship between painful procedures and analgesia for neonates at risk for NI. ⋯ Neonates at the highest risk for NI had the greatest number of painful procedures and the least amount of opioids administered during the first day of life. There was no relationship between painful procedures and analgesic use in this group. As these infants are vulnerable to pain and its consequences, the rational underlying health professional strategies regarding painful procedures and analgesic use for procedural pain in this population urgently awaits exploration.
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The inhibitory activity of gamma-aminobutyric acid (GABA) is considered critical in setting the conditions for synaptic plasticity, and many studies support an important role of GABA in the suppression of nociceptive transmission in the dorsal horn. Consequently, any injury-induced modification of the GABA action has the potential to critically modify spinal synaptic plasticity. We have previously reported that chronic constriction injury of the sciatic nerve was accompanied by long-lasting potentiation of superficial spinal dorsal horn field potentials following high-frequency tetanus. ⋯ In separate but related Western immunoblot experiments, we also established that the chronic constriction injury was accompanied by significant decreases in the content of the GABA transporter GAT-1. These data demonstrated that GABA-A receptor agonists may effectively influence the expression of long-lasting synaptic plasticity in the spinal dorsal horn, and that an injury-induced loss in GABA transporter content may have contributed to a depletion of GABA from its terminals within the spinal dorsal horn. These data lent further support to the notion that the loss of GABA inhibition may have important consequences for the development of neuropathic pain.
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Despite widespread use of the 0-10 numeric rating scale (NRS) of pain intensity, relatively little is known about the meaning of decreases in pain intensity assessed by means of this scale to patients. We aimed to establish the meaning to patients of declines in pain intensity and percent pain reduction. Upon arrival to the postanesthesia care unit, postsurgical patients rated their baseline pain intensity on both a 0-10 NRS and on a 4-point verbal scale. ⋯ For patients with severe pain, the decrease in NRS pain score and the percentage of pain relief had to be larger to obtain similar degrees of pain relief. The change in pain intensity that is meaningful to patients increases as the severity of their baseline pain increases. The present findings are applicable in the clinical setting and research arena to assess treatment efficacy.
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Analgesic effects of cannabimimetic compounds have been known to be related to their central effects. Cannabinoid receptors also exist in the periphery but their role in pain perception has been remained to be clarified. Therefore, we assessed topical antinociceptive effects of WIN 55, 212-2, a mixed CB(1) and CB(2) receptors agonist, in mice using tail-flick test. ⋯ Our findings support that cannabinoid system participates in buffering the emerging pain signals at the peripheral sites in addition to their spinal and supraspinal sites of action. In addition, an antinociceptive synergy between topical and spinal cannabinoid actions exists. These results also indicate that topically administered cannabinoid agonists may reduce pain without the dysphoric side effects and abuse potential of centrally acting cannabimimetic drugs.