Articles: hyperalgesia.
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Comparative Study
Comparison of self-reported cutaneous allodynia and brushing allodynia during migraine attacks.
This study compares the results of brushing allodynia (BA) during migraine attacks to those of self-reported cutaneous allodynia. We recruited 100 patients (20 with chronic migraine, 80 with episodic migraine) and performed a gauze-brushing test to detect BA. A previous experience of cutaneous allodynia was queried. ⋯ Some allodynia symptoms, including avoidance of washing hair, touching the head, combing hair and lying on the site of head pain, were associated with BA (all p < .05). Our study showed that BA during migraine attacks correlated well with prior allodynia symptoms. The frequencies of BA and self-reported allodynia depend on the composition of different migraine subtypes and the timing of the gauze-brushing test.
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Ann. N. Y. Acad. Sci. · Jun 2010
Role of NKCC1 and KCC2 in the development of chronic neuropathic pain following spinal cord injury.
Neuropathic pain is a common problem following spinal cord injury (SCI). Effective analgesic therapy has been hampered by the lack of knowledge about the mechanisms underlying post-SCI neuropathic pain. Current evidence suggests GABAergic spinal nociceptive processing is a critical functional node in this complex phenotype, representing a potential target for therapeutic intervention. ⋯ Inhibition of NKCC1 with its potent antagonist bumetanide reduces pain behavior in rats following SCI. Moreover, the injured spinal cord tissues exhibit a significant transient upregulation of NKCC1 protein and a concurrent downregulation of KCC2 protein. Thus, imbalanced function of NKCC1 and KCC2 may contribute to the induction and maintenance of the chronic neuropathic pain following SCI.
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J Pain Palliat Care Pharmacother · Jun 2010
Patients with chronic pain after abdominal surgery show less preoperative endogenous pain inhibition and more postoperative hyperalgesia: a pilot study.
Chronic pain is common and undesirable after surgery. Progression from acute to chronic pain involves altered pain processing. The authors studied relationships between presence of chronic pain versus preoperative descending pain control (diffuse noxious inhibitory controls; DNICs) and postoperative persistence and spread of skin and deep tissue hyperalgesia (change in electric/pressure pain tolerance thresholds; ePTT/pPTT) up to 6 months postoperatively. ⋯ More inhibitory pDNIC was linked to less postoperative leg deep tissue hyperalgesia, without affecting pain VAS. This pilot study for the first time links chronic pain after surgery, poorer preoperative inhibitory pain modulation (DNIC), and greater postoperative degree, persistence, and spread of hyperalgesia. If confirmed, these results support the potential clinical utility of perioperative pain processing testing.
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Exp Clin Psychopharmacol · Jun 2010
Randomized Controlled Trial Clinical TrialDifferential effect of codeine on thermal nociceptive sensitivity in sleepy versus nonsleepy healthy subjects.
Basal sleepiness-alertness modulates drug effects. Sleepiness produced by sleep restriction leads to increased nociceptive sensitivity, suggesting opioid analgesia may also be modulated by sleepiness-alertness. This study compared thermal nociceptive sensitivity in sleepy versus nonsleepy participants after codeine or placebo. ⋯ More important, there was a Group x Drug interaction with codeine increasing FWL in the nonsleepy, but not the sleepy, group. These data show the analgesic effects of codeine are diminished in sleepy versus nonsleepy individuals. They suggest clinical differences in response to analgesics are partly explained by basal state of sleepiness-alertness.
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Can. J. Physiol. Pharmacol. · Jun 2010
Endothelins implicated in referred mechanical hyperalgesia associated with colitis induced by TNBS in mice.
This study evaluated the contribution of endothelins to changes in sensitivity to mechanical stimulation of the lower abdomen and hind paw associated with 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. The frequency of withdrawal responses to 10 consecutive applications of von Frey probes to the lower abdomen (0.07 g) or hind paw (0.4 g) was assessed in male BALB/c mice before and after intracolonic TNBS injection (0.5 mg in 100 microL of 35% ethanol). TNBS (0.5 mg) induced referred mechanical hyperalgesia in the abdomen (response frequencies at 24 h: saline 11.0% +/- 3.1%, TNBS 48.0% +/- 6.9%) and hind paw (frequencies at 24 h: saline 12.5% +/- 4.7%, TNBS 47.1% +/- 7.1%) lasting up to 72 and 48 h, respectively. ⋯ Atrasentan (ETA receptor antagonist; 10 and 30 mg/kg, i.v.) given 24 h after TNBS abolished hind paw and abdominal mechanical hyperalgesia for 2-3 h. A-192621 (ETB receptor antagonist; 20 mg/kg, i.v.) attenuated abdominal mechanical hyperalgesia at the 3 h time point only. Thus, endothelins contribute importantly to abdominal and hind paw referred mechanical hyperalgesia during TNBS-induced colitis mainly through ETA receptor-signaled mechanisms.