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Contribution of the peripheral 5-HT2A receptor to mechanical hyperalgesia in a rat model of neuropathic pain
- Source :
-
Neurochemistry International . Nov2005, Vol. 47 Issue 6, p394-400. 7p. - Publication Year :
- 2005
-
Abstract
- Abstract: We investigated the effect of 5-HT receptor antagonists on mechanical hyperalgesia observed in a neuropathic pain rat model prepared by chronic constriction injury of the sciatic nerve. NAN-190, a 5-HT1A receptor antagonist, (−)-pindolol, a 5-HT1A/1B receptor antagonist, and tropisetron, a 5-HT3/4 receptor antagonist, did not affect the pain threshold in the hyperalgesic hind limb to the same extent as in the normal hind limb. However, sarpogrelate and ketanserin, 5-HT2A receptor antagonists, significantly elevated the pain threshold in the hyperalgesic hind limb, but not in the normal hind limb. In spite of its high affinity for the 5-HT2A receptor, methysergide only slightly elevated the pain threshold in the hyperalgesic hind limb. Pre-treatment with methysergide significantly antagonized the inhibitory effect of sarpogrelate on hyperalgesia. Furthermore, the 5-HT2A receptor specific binding activity of 3H-ketanserin determined for the hyperalgesic hind limb did not differ from that of the normal hind limb. From these results, we propose that the 5-HT2A receptor in the hyperalgesic hind paw function as an agonist-independent active receptor following constriction of the sciatic nerve, and that sarpogrelate and ketanserin act as inverse agonists of this receptor and suppress its activation. Methysergide may act as a neutral antagonist that blocks the effect of inverse agonists on the 5-HT2A receptor. [Copyright &y& Elsevier]
- Subjects :
- *HYPERALGESIA
*SEROTONIN antagonists
*ANTIHYPERTENSIVE agents
*PAIN
Subjects
Details
- Language :
- English
- ISSN :
- 01970186
- Volume :
- 47
- Issue :
- 6
- Database :
- Academic Search Index
- Journal :
- Neurochemistry International
- Publication Type :
- Academic Journal
- Accession number :
- 18282096
- Full Text :
- https://doi.org/10.1016/j.neuint.2005.06.002