title: Forced swim-induced musculoskeletal hyperalgesia is mediated by CRF2 receptors but not by TRPV1 receptors.
abstract: The exacerbation of musculoskeletal pain by stress in humans is modeled by the musculoskeletal hyperalgesia in rodents following a forced swim. We hypothesized that stress-sensitive corticotropin releasing factor (CRF) receptors and transient receptor vanilloid 1 (TRPV1) receptors are responsible for the swim stress-induced musculoskeletal hyperalgesia. We confirmed that a cold swim (26 °C) caused a transient, morphine-sensitive decrease in grip force responses reflecting musculoskeletal hyperalgesia in mice. Pretreatment with the CRF2 receptor antagonist astressin 2B, but not the CRF1 receptor antagonist NBI-35965, attenuated this hyperalgesia. Desensitizing the TRPV1 receptor centrally or peripherally using desensitizing doses of resiniferatoxin (RTX) failed to prevent the musculoskeletal hyperalgesia produced by cold swim. SB-366791, a TRPV1 antagonist, also failed to influence swim-induced hyperalgesia. Together these data indicate that swim stress-induced musculoskeletal hyperalgesia is mediated, in part, by CRF2 receptors but is independent of the TRPV1 receptor.
authors.affiliation: Department of Veterinary and Biomedical Sciences, University of Minnesota, 1988 Fitch Avenue Room 295, St. Paul, MN 55108, USA.
authors.forename: Ramy E
authors.initials: RE
authors.lastname: Abdelhamid
authors.forename: Katalin J
authors.initials: KJ
authors.lastname: Kovacs
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Pasley
authors.forename: Myra G
authors.initials: MG
authors.lastname: Nunez
authors.forename: Alice A
authors.initials: AA
authors.lastname: Larson
mesh_terms: D000073:Acenaphthenes / Q000627:therapeutic use; D000700:Analgesics / Q000627:therapeutic use; D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003080:Cold Temperature / Q000009:adverse effects; D004195:Disease Models, Animal; D004224:Diterpenes / Q000627:therapeutic use; D005260:Female; D006930:Hyperalgesia / Q000188:drug therapy / Q000209:etiology* / Q000378:metabolism*; D051379:Mice; D009020:Morphine / Q000627:therapeutic use; D053580:Muscle Strength / Q000187:drug effects; D059352:Musculoskeletal Pain / Q000209:etiology* / Q000378:metabolism*; D010147:Pain Measurement; D010446:Peptide Fragments / Q000627:therapeutic use; D010456:Peptides, Cyclic / Q000627:therapeutic use; D011930:Reaction Time / Q000187:drug effects; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013550:Swimming / Q000523:psychology; D050916:TRPV Cation Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: C504986:6-cyclopropylmethyl-2-(2,4-dichlorophenyl)-7-ethyl-4-methyl-7,8-dihydro-6H-1,3,6,8a-tetraazaacenaphthylene; D000073:Acenaphthenes; D000700:Analgesics; C101531:CRF receptor type 2; D004224:Diterpenes; D010446:Peptide Fragments; D010456:Peptides, Cyclic; D018019:Receptors, Corticotropin-Releasing Hormone; D050916:TRPV Cation Channels; C493921:TRPV1 protein, mouse; C528574:astressin-2B; D009020:Morphine; C024353:resiniferatoxin