title: Sex difference in peripheral arterial response to cold exposure.
abstract: BACKGROUND
  In Japan, there is a symptom commonly referred to as "Hie-sho", which is a feeling of coldness or chill in a particular part of the body, and it can sometimes be unendurable. This phenomenon is known to occur more frequently in women. The present study used synchrotron radiation micro-angiography (SRMA) to examine the hypothesis that this feeling is derived from a sex difference in the vascular response to coldness.
  
  
  RESULTS
  The hind limb of male (Group M) and female (Group F) Wistar rats was exposed to cold and the tissue temperature was recorded. SRMA with a spatial resolution of 26 microm was used to measure arterial diameter. The reduction in temperature brought on by cold exposure was significantly larger in Group F than in Group M (p<0.05). SRMA showed that the arteries were dilated by cold exposure in both groups; however, the percentage dilatation in response was statistically small in Group F (69+/-40%) compared with Group M (118+/-73%) (p<0.05).
  
  
  CONCLUSIONS
  Arteries in the limbs of female rats did not expand as much as those of the males in response to cold exposure, which may explain why women feel the cold more than men.
authors.affiliation: Department of Cardiovascular Surgery, Graduate School of Comprehensive Human Science, University of Tsukuba, Japan.
authors.forename: Fujio
authors.initials: F
authors.lastname: Sato
authors.forename: Shonosuke
authors.initials: S
authors.lastname: Matsushita
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Hyodo
authors.forename: Shinji
authors.initials: S
authors.lastname: Akishima
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Imazuru
authors.forename: Chiho
authors.initials: C
authors.lastname: Tokunaga
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Enomoto
authors.forename: Shinya
authors.initials: S
authors.lastname: Kanemoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hiramatsu
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Sakakibara
mesh_terms: D000792:Angiography / Q000295:instrumentation; D000818:Animals; D001160:Arterioles / Q000502:physiology; D001831:Body Temperature; D003080:Cold Temperature; D005260:Female; D006614:Hindlimb / Q000098:blood supply*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012737:Sex Factors; D017356:Synchrotrons; D014664:Vasodilation