Pain
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The unpleasantness of itching is reduced by cooling. Although previous research suggests the presence of a central itch modulation system, there is little documentation about the modulation system in the brain. In the present study, we investigated the modulating system of the itching sensation in human brains using positron emission tomography and H(2) (15)O. ⋯ PAG is well known to be a modulating noxious stimulus. Here we hypothesize that the activation of PAG may also be related to the itch modulation. These findings indicate that the modified brain activities in the PAG, the cingulate, the frontal and the parietal cortex might be associated with the itch modulation in the central nervous system and that the S2 might not be primarily involved in processing the itching perception in the brain since the activity of S2 was not observed in any concentration of itching stimuli.
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Cyclooxygenase inhibitors demonstrate effective antinociception in many clinical and experimental pain models. Acute uterine cervical distension (UCD) forms the basis for obstetric and some gynecologic pain, and acute UCD in rats results in nocifensor reflexes which are inhibited by morphine in animals lacking, but not in animals with circulating estrogen. We studied the antinociceptive effect of intravenous and intrathecal injection of the cyclooxygenase inhibitor, ketorolac in acute UCD rats and its dependency on estrogen. ⋯ Intravenous ketorolac produced dose dependent inhibition of the responses to UCD, but intrathecal ketorolac was ineffective at the maximum test dose (300 microg). Estrogen replacement did not affect the stimulus response or maximum efficacy of ketorolac. Unlike morphine, which reduces response to UCD by spinal and supraspinal mechanisms and whose action is blocked by estrogen, the cyclooxygenase inhibitor, ketorolac acts at an estrogen-independent, non spinal site.
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The pathophysiological mechanisms underlying sciatica and back pain are not well understood. In the present study, a sciatica model was developed to investigate the contributions of inflammation and compression of the dorsal root (DR). The procedure used autologous disc to apply direct pressure to the L5 DR (disc compression, DC group). ⋯ Finally, rats in all groups showed normal motor function and body weight increase. These data suggest that this model is suitable to investigate the mechanisms of sciatica and inflammation as well as mechanical compression is involved in the pathogenesis of this condition. Moreover, AF and NP may contribute similarly to the development of sciatica and back pain.
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Randomized Controlled Trial Comparative Study Clinical Trial
Intrathecal, but not intravenous adenosine reduces allodynia in patients with neuropathic pain.
Intrathecal adenosine reduces allodynia from intradermal capsaicin in human volunteers, and reduces hypersensitivity to mechanical stimuli in animals with nerve injury. Although both intrathecal and intravenous adenosine have been reported to relieve pain in patients with neuropathic pain, there are no controlled trials of this therapy. In order to determine the effect of adenosine, seven patients with chronic neuropathic pain and stable areas of mechanical hyperalgesia and allodynia were recruited. ⋯ Intrathecal, but not intravenous adenosine, caused backache in five of seven patients, lasting 6 h. These results indicate that intrathecal adenosine reduces allodynia and pain from stimulation in the area of allodynia, whereas the same dose of adenosine intravenously was ineffective. Given the modest effect and common side effects, the role for intrathecal adenosine as a sole agent for the treatment of neuropathic pain may be limited.
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Randomized Controlled Trial Clinical Trial
Potential utility of the peripheral analgesic properties of morphine in stomatitis-related pain: a pilot study.
To determine the potential clinical utility of peripheral opioid action using a clinical model of cancer treatment-induced inflammation and pain that allowed for topical application of morphine in the damaged tissue (oral mucosa). This pilot study followed a two blocks design. Ten patients with painful oral mucositis were enrolled in the first block (dose-response relationship finding) and randomized in two groups to receive oral rinses with 15 ml of either 1 per thousand or 2 per thousand morphine solution. ⋯ During our experiment no systemically active detectable concentrations of morphine were found (GC-MS analysis). The most important side effect attributable to morphine mouthwashes was burning/itching sensation (very mild to mild intensity). Patients with painful chemoradiotherapy-induced stomatitis could be alleviated using topical morphine mouthwashes.