title: The antagonistic effect of the sigma 1 receptor ligand (+)-MR200 on persistent pain induced by inflammation.
abstract: OBJECTIVE
  The sigma 1 (σ1) receptor, which is widely distributed in the CNS in areas that are known to be important for pain control, may play a role in persistent pain characterized by the hypersensitivity of nociceptive transmission. Here, we investigated the effect of σ1 blockade in an inflammatory pain model.
  
  
  METHODS
  An intraplantar injection of carrageenan (2 %) was used to induce paw inflammation. The effects of the σ1 antagonist (+)-MR200, given subcutaneously at a dose of 0.1, 0.25, 0.5,1, 1.5, and 2 mg/kg prior to injection of carrageenan, on inflammatory pain and inflammation were assessed. Mechanical allodynia with von Frey filaments, thermal hyperalgesia with the plantar test and edema evaluation with a plethysmometer were measured. Intergroup comparisons were assessed by one- or two-way analysis of variance when appropriate, followed by post-hoc tests (Dunnett's test for one-way or Bonferroni for two-way ANOVA).
  
  
  RESULTS
  (+)-MR200 dose-dependently prevented allodynia and hyperalgesia induced by carrageenan. Furthermore, it reduced paw edema with a significant inhibition percentage of 37.82 % at 3 h after carrageenan treatment.
  
  
  CONCLUSIONS
  The blockade of the σ1 receptor with the selective antagonist (+)-MR200 may contribute to the suppression of the typical symptoms of inflammatory pain.
authors: Pharmacology and Toxicology Section, Department of Drug Sciences, University of Catania, 95125, Catania, Italy.
authors: Carmela
authors: C
authors: Parenti
authors: Agostino
authors: A
authors: Marrazzo
authors: Giuseppina
authors: G
authors: Aricò
authors: Rosalba
authors: R
authors: Parenti
authors: Lorella
authors: L
authors: Pasquinucci
authors: Simone
authors: S
authors: Ronsisvalle
authors: Giuseppe
authors: G
authors: Ronsisvalle
authors: Giovanna Maria
authors: GM
authors: Scoto
mesh_terms: D000818:Animals; D002351:Carrageenan; D059350:Chronic Pain / Q000188:drug therapy* / Q000209:etiology; D003521:Cyclopropanes / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004487:Edema / Q000139:chemically induced / Q000188:drug therapy / Q000473:pathology; D005528:Foot / Q000473:pathology; D006358:Hot Temperature; D006930:Hyperalgesia / Q000188:drug therapy; D007249:Inflammation / Q000139:chemically induced / Q000150:complications*; D008297:Male; D010812:Physical Stimulation; D010880:Piperidines / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017480:Receptors, sigma / Q000037:antagonists & inhibitors*; D000097605:Sigma-1 Receptor
chemical_list: D002351:Carrageenan; D003521:Cyclopropanes; D010880:Piperidines; D017480:Receptors, sigma; D000097605:Sigma-1 Receptor; C479880:(+)-methyl 2-((4-(4-chlorophenyl)-4-hydroxypiperidin-1-yl)methyl)-1-phenylcyclopropanecarboxylate