title: A technique to measure cold adaptation in freely behaving mice.
abstract: BACKGROUND
  Adaptation to environmental temperature is essential for survival in seasonal areas. The mechanisms of adaptation have been studied in vitro, but it has not been quantified in vivo.
  
  
  METHODS
  The extended Cold Plantar Assay (eCPA) cools the entire testing environment. Once the desired environmental temperature has been reached, a separate focal cold stimulus is applied to the hindpaw and the latency to withdrawal is recorded as a proxy for cold sensitivity.
  
  
  RESULTS
  Using this technique, we can test the cold responsiveness of freely behaving mice at ambient temperatures ranging from 5°C to 30°C. The responses are consistent and unambiguous, and the environmental temperatures generated are reproducible. We are also able to measure cold responsiveness as animals are in the process of adapting to cold environments.
  
  
  CONCLUSIONS
  Existing methods, such as the dynamic cold plate and the 2-plate preference assay test how mice respond to cold environments, but cannot assess how the thresholds for response are changed by acclimation in cold environments. Additionally, the eCPA requires very little specialized equipment, can test many mice at the same time on one apparatus, and has an objective readout.
  
  
  CONCLUSIONS
  The extended Cold Plantar assay is a significant methodological improvement, allowing the assessment of cold responsiveness in freely behaving mice at a wide range of environmental temperature conditions and during cold adaptation.
authors.affiliation: Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Neuroscience Program, Washington University School of Medicine, St. Louis, MO 63110, USA; Medical Scientist Training Program, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Brenner
authors.affiliation: Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Sherri K
authors.initials: SK
authors.lastname: Vogt
authors.affiliation: Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Neuroscience Program, Washington University School of Medicine, St. Louis, MO 63110, USA. Electronic address: gereaur@wustl.edu.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Gereau
mesh_terms: D000222:Adaptation, Physiological; D000704:Analysis of Variance; D000818:Animals; D003080:Cold Temperature; D006614:Hindlimb; D006799:Housing, Animal; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017288:Pain Threshold; D010812:Physical Stimulation / Q000295:instrumentation / Q000379:methods*
keywords: Acetone; Adaptation; Cold; Cold plate; Pain; Thermosensation