Pain
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Irritable bowel syndrome (IBS) is one of the most common gastrointestinal illnesses and is characterized by altered visceral perception. The aim of the study was to determine if local anesthetic blockade of peripheral visceral nociceptive input reduces both visceral and cutaneous secondary hyperalgesia in IBS patients. Ten women with IBS (mean age 30+/-10 years) and ten control subjects (all women) (mean age 29+/-7 years) rated pain intensity and unpleasantness to distension of the rectum (35 mmHg) and thermal stimulation (47 degrees C) of the foot before and after rectal administration of either lidocaine jelly or saline jelly in a double blind crossover design. ⋯ The results of this study support the hypothesis that local anesthetic blockade of peripheral impulse input from the rectum/colon reduces both visceral and cutaneous secondary hyperalgesia in IBS patients. The results provide further evidence that visceral hyperalgesia and secondary cutaneous hyperalgesia in IBS reflects central sensitization mechanisms that are dynamically maintained by tonic impulse input from the rectum/colon. Rectal administration of lidocaine jelly may also be a safe and effective means of reducing pain symptoms in IBS patients.
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Fear of movement/(re)injury and its associated avoidance behavior have shown to be strongly associated with functional disability in chronic low back pain. In acute low back pain disability, the role of pain-related fear has received little research attention so far. Measures of pain-related fear such as the Tampa Scale for Kinesiophobia (TSK) are increasingly being used in primary care. ⋯ Additionally, and in contrast to what is often observed in chronic pain, disability, and to a lesser degree participation, were also associated with pain intensity. Finally, the association between pain-related fear, pain intensity and participation was indeed mediated by disability. The results suggest that early on in the development of LBP disability, the successful reduction of pain-related fear and disability might foster increased participation in daily and social life activities.
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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.