title: Voluntary movements as a possible non-reflexive pain assay.
abstract: BACKGROUND
  The quantification of pain intensity in vivo is essential for identifying the mechanisms of various types of pain or for evaluating the effects of different analgesics. A variety of behavioral tests for pain measurement have been devised, but many are limited because animals are physically restricted, which affects pain sensation. In this study, pain assessment was attempted with minimal physical restriction, and voluntary movements of unrestrained animals were used to evaluate the intensities of various types of pain.
  
  
  RESULTS
  The number of times animals reared or total distances traveled was measured using a motion-tracking device and found to be markedly reduced in carrageenan-induced inflammatory, acetic acid-induced visceral, and streptozotocin-induced neuropathic pain tests. These two voluntary movement parameters were found to be highly correlated with paw withdrawal latency from irradiating heat. In addition, these parameters were markedly reversed by morphine and by non-steroidal anti-inflammatory drugs in inflammatory pain models. These parameters were also useful to detect hypoalgesia in TRPV1⁻/⁻ mice.
  
  
  CONCLUSIONS
  These results suggest that parameters of voluntary movement, such as, number of rearing and total distance moved, are effective indicators of pain intensity for many types of pain and that they can be used to evaluate degree of pain perception.
authors.affiliation: Sensory Research Center, CRI, College of Pharmacy, Seoul National University, Seoul 151-742, Korea.
authors.forename: Hawon
authors.initials: H
authors.lastname: Cho
authors.forename: Yongwoo
authors.initials: Y
authors.lastname: Jang
authors.forename: Byeongjun
authors.initials: B
authors.lastname: Lee
authors.forename: Hyeyoun
authors.initials: H
authors.lastname: Chun
authors.forename: Jooyoung
authors.initials: J
authors.lastname: Jung
authors.forename: Sung Min
authors.initials: SM
authors.lastname: Kim
authors.forename: Sun Wook
authors.initials: SW
authors.lastname: Hwang
authors.forename: Uhtaek
authors.initials: U
authors.lastname: Oh
mesh_terms: D000700:Analgesics / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology / Q000627:therapeutic use; D002351:Carrageenan / Q000009:adverse effects; D004195:Disease Models, Animal; D007249:Inflammation / Q000139:chemically induced / Q000188:drug therapy; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009043:Motor Activity / Q000502:physiology*; D009437:Neuralgia / Q000139:chemically induced / Q000188:drug therapy; D010146:Pain; D010147:Pain Measurement / Q000379:methods / Q000592:standards*; D051381:Rats; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism
chemical_list: D000700:Analgesics; D000894:Anti-Inflammatory Agents, Non-Steroidal; D050916:TRPV Cation Channels; C493921:TRPV1 protein, mouse; D002351:Carrageenan