Articles: hyperalgesia.
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Anesthesia and analgesia · Mar 2010
N-antipyrine-3, 4-dichloromaleimide, an effective cyclic imide for the treatment of chronic pain: the role of the glutamatergic system.
In recent years, cyclic imides have attracted the attention of the scientific community because of their promising therapeutic potential. Studies with the compound N-antipyrine-3,4-dichloromaleimide (NA-3,4-DCM) also demonstrated an antinociceptive effect in formalin or capsaicin models of nociception, and that it reduced acetic acid-induced abdominal writhing in mice. ⋯ These results provide strong evidence that NA-3,4-DCM produces antihypernociception in mice at peripheral, spinal, and supraspinal sites, and that interaction with the group I metabotropic glutamate receptors and NMDA receptors contributes to the mechanisms underlying its effect.
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This study investigated the role of TRPA1 in the development and maintenance of mechanical and cold hyperalgesia in persistent inflammation induced by Complete Freund's Adjuvant (CFA) in mice. The intraplantar (i.pl.) injection of CFA induced a long lasting (28 days) hyperalgesia for both mechanical and thermal (cold) stimuli. The intraperitoneal (i.p., 30-300 mg/kg), intraplantar (i.pl., 100 microg/site) or intrathecal (i.t., 10 microg/site) injection of the TRPA1 selective antagonist HC-030031 significantly reduced the mechanical hyperalgesia evaluated by the von Frey hair test. ⋯ Interestingly, both TRPA1 protein expression and mRNA were over-expressed in spinal cord and dorsal root ganglia (DRG) of mice treated with CFA, an effect that was fully prevented by the pre-treatment with the TRPA1 antagonist HC-030031. Collectively, the present results showed that TRPA1 present at either peripheral or spinal sites play a relevant role in the development and maintenance of both mechanical and cold hyperalgesia during CFA-induced inflammation. Thus, TRPA1 selective antagonists represent promising candidates to treat hyperalgesia in persistent inflammatory states.
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Scand. J. Gastroenterol. · Mar 2010
Comparative StudyAcid hypersensitivity in patients with eosinophilic oesophagitis.
Painful symptoms are prevalent in patients with eosinophilic oesophagitis but experimental data are sparse. The aim of this study was to compare the pain response to experimental oesophageal stimulation in 14 patients with eosinophilic oesophagitis and 15 healthy volunteers. ⋯ Patients with eosinophilic oesophagitis are hypersensitive to acid perfused in the oesophagus, and pathophysiologic findings are likely confined to the peripheral tissue. Reflux from physiological acid may play a role in the symptoms of eosinophilic oesophagitis.
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Chronic muscle pain of the neck, shoulder and low back is quite common and often related to a stressed condition. In this study we tried to make a model of long-lasting muscle mechanical hyperalgesia based on one type of stress, repeated cold stress (RCS) (Kita T, Hata T, Yoneda R, Okage T. Stress state caused by alternation of rhythm in environmental temperature, and the functional disorders in mice and rats. ⋯ Bilateral cutaneous punctuate hyperalgesia was also observed with RCS at -3 degrees C. Intramuscular injection of lidocaine confirmed that the muscle was hyperalgesic. RCS might serve as a useful model for study of the mechanism of chronic muscle pain and its treatment.
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Tramadol is an analgesic drug, and its mechanism of action is believed to be mediated by the mu-opioid receptor. A further action of tramadol has been identified as blocking the reuptake of serotonin (5-HT). One of the most recently identified subtypes of 5-HT receptor is the 5-HT7 receptor. Thus, the authors aimed to examine the potential role of serotonergic descending bulbospinal pathways and spinal 5-HT7 receptors compared with that of the 5-HT2A and 5-HT3 receptors in the antinociceptive and antihyperalgesic effects of tramadol and its major active metabolite O-desmethyltramadol (M1) on phasic and postoperative pain models. ⋯ These findings suggest that the descending serotonergic pathways and spinal 5-HT7 receptors play a crucial role in the antinociceptive and antihyperalgesic effects of tramadol and M1.