title: Attenuated fever response in mice lacking TRPV1.
abstract: TRPV1, the capsaicin receptor, is expressed not only in nociceptive neurons, but also in other locations, including the hypothalamus. Studies involving systemic or intrahypothalamic capsaicin administration have suggested a role for TRPV1 in body temperature control. To explore this possibility, we examined thermoregulatory responses in TRPV1-/- mice. These mutant animals exhibited no obvious changes in circadian body temperature fluctuation, tolerance to increased (35 degrees C) or decreased (4 degrees C) ambient temperature or ethanol-induced hypothermia. In contrast, fever production in response to the bacterial pyrogen, lipopolysaccharide (LPS) was significantly attenuated in TRPV1-/- mice. Despite this finding, we detected no significant differences between TRPV1-/- and control mice in the extent of LPS-induced c-Fos expression in numerous fever-related brain subregions. These results suggest that TRPV1 participates in the generation of polyphasic fever, perhaps at sites outside the brain.
authors.affiliation: Departments of Biological Chemistry and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Tohko
authors.initials: T
authors.lastname: Iida
authors.forename: Isao
authors.initials: I
authors.lastname: Shimizu
authors.forename: Michele L
authors.initials: ML
authors.lastname: Nealen
authors.forename: Ashley
authors.initials: A
authors.lastname: Campbell
authors.forename: Michael
authors.initials: M
authors.lastname: Caterina
mesh_terms: D000818:Animals; D001833:Body Temperature Regulation / Q000235:genetics*; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology; D003080:Cold Temperature; D005334:Fever / Q000139:chemically induced / Q000235:genetics*; D006358:Hot Temperature; D007473:Ion Channels / Q000172:deficiency*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D011749:Pyrogens / Q000494:pharmacology; D050916:TRPV Cation Channels
chemical_list: D007473:Ion Channels; D008070:Lipopolysaccharides; D016760:Proto-Oncogene Proteins c-fos; D011749:Pyrogens; D050916:TRPV Cation Channels; C493921:TRPV1 protein, mouse