title: Thermal hyperalgesia and light touch allodynia after intradermal Mycobacterium butyricum administration in rat.
abstract: We examined the time course (7 weeks) of thermal hyperalgesia and light touch allodynia in rats after intradermal administration of Mycobacterium butyricum. Nociceptive thresholds to heat and light touch were assessed. Paw edema and temperature, motor function, body weight, and propioception were also tested. Some rats developed arthritis (named AA rats) but others did not (named non-AA rats). Both groups were compared with healthy animals. Persistent hyperalgesia was found in both groups; in AA rats it appeared before clinical evidence of arthritis. Transient allodynia ocurred only after edema development and fell when edema decreased. Motor function was impaired only in AA rats. The results of this study demonstrate that hyperalgesia, but not allodynia, appeared after Mycobacterium butyricum in both groups, suggesting that changes in sensitivity were not merely the result of local hypersensitivity of the inflamed tissue, but may also be due to alterations in nociception in the central nervous system.
authors.affiliation: Departament de Fisiologia-Divisió IV, Unitat de Biofarmàcia i Farmacocinètica, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Maria Isabel
authors.initials: MI
authors.lastname: Arévalo
authors.forename: Elvira
authors.initials: E
authors.lastname: Escribano
authors.forename: Ana
authors.initials: A
authors.lastname: Calpena
authors.forename: Josep
authors.initials: J
authors.lastname: Domenech
authors.forename: Josep
authors.initials: J
authors.lastname: Queralt
mesh_terms: D000818:Animals; D001168:Arthritis / Q000382:microbiology; D001831:Body Temperature; D004195:Disease Models, Animal; D006930:Hyperalgesia / Q000209:etiology / Q000382:microbiology*; D007249:Inflammation / Q000473:pathology*; D007271:Injections, Intradermal; D008297:Male; D009161:Mycobacterium; D010146:Pain / Q000209:etiology / Q000382:microbiology; D010147:Pain Measurement; D051381:Rats; D017207:Rats, Sprague-Dawley; D020886:Somatosensory Disorders / Q000209:etiology / Q000382:microbiology*; D013995:Time