title: Varying perceived social threat modulates pain behavior in male mice.
abstract: We previously demonstrated that male mice display significantly reduced pain behavior on the acetic acid abdominal constriction test when confined in close proximity to a stranger male mouse. We show here the testosterone-dependence (via castration and testosterone propionate replacement) of this phenomenon, likely a form of (social) stress-induced analgesia. However, when similar male dyads are separated by vertical metal bars, allowing only partial physical contact, we find that the mice exhibit hyperalgesia, not analgesia, in response to both acetic acid injection and noxious radiant heat, relative to testing in isolation. This finding is specific to same-sex male dyads, and no change in nociceptive sensitivity is observed when males are tested in the presence of a female conspecific. We propose that pain sensitivity varies with respect to the severity of the social threat: mild social threat produces hyperalgesia and more severe social threat produces analgesia.
  
  
  CONCLUSIONS
  This work highlights the importance of social threat in modulating pain behavior in a sex-specific manner. The findings add to a growing body of evidence that social factors affect pain behavior in mice, thus allowing the study of the mechanistic underpinnings of social modulation of pain in humans.
authors.affiliation: Department of Psychology and Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada.
authors.forename: Dale J
authors.initials: DJ
authors.lastname: Langford
authors.forename: Alexander H
authors.initials: AH
authors.lastname: Tuttle
authors.forename: Ciara
authors.initials: C
authors.lastname: Briscoe
authors.forename: Colin
authors.initials: C
authors.lastname: Harvey-Lewis
authors.forename: Inna
authors.initials: I
authors.lastname: Baran
authors.forename: Patrick
authors.initials: P
authors.lastname: Gleeson
authors.forename: David B
authors.initials: DB
authors.lastname: Fischer
authors.forename: Michele
authors.initials: M
authors.lastname: Buonora
authors.forename: Wendy F
authors.initials: WF
authors.lastname: Sternberg
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Mogil
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D002369:Castration; D003345:Corticosterone / Q000097:blood; D004195:Disease Models, Animal; D005243:Feces; D005260:Female; D012739:Gonadal Steroid Hormones / Q000008:administration & dosage*; D007398:Interpersonal Relations; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010146:Pain / Q000188:drug therapy / Q000503:physiopathology* / Q000523:psychology*; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology*; D013739:Testosterone / Q000627:therapeutic use
chemical_list: D012739:Gonadal Steroid Hormones; D013739:Testosterone; D003345:Corticosterone