The effect of hypothermic ischemia on the alpha-adrenergic mechanisms of the canine tibia vascular bed

J Orthop Res. 1992 Jan;10(1):149-55. doi: 10.1002/jor.1100100118.

Abstract

The effect of hypothermic ischemia on alpha-1 and -2 adrenergic receptor mediated vasoconstriction has been studied in an in vitro perfused canine tibia preparation. Bones were perfused at a constant rate with aerated (95% O2, 5% CO2) modified Krebs Ringer solution and the effect of bolus injections of norepinephrine (0.025-6.4 nmol) on the perfusion pressure was studied. For all bones the first dose-response curve was produced under control conditions. In one group the second dose-response curve was generated during a constant infusion of prazosin (alpha-1 adrenergic antagonist); in another it was produced during a constant infusion of rauwolscine (alpha-2 adrenergic antagonist); in the control group it was generated under control conditions. The results demonstrate that, after 48 h of hypothermic ischemia, alpha-1 adrenergic-mediated vasoconstriction was significantly attenuated (p less than 0.001). However, alpha-2 adrenergic-mediated vasoconstriction was unaffected by increasing periods of hypothermic ischemia.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blood Vessels / innervation
  • Dogs
  • Dose-Response Relationship, Drug
  • Hypothermia / physiopathology*
  • In Vitro Techniques
  • Ischemia / physiopathology*
  • Norepinephrine / pharmacology
  • Perfusion
  • Pressure
  • Receptors, Adrenergic, alpha / physiology*
  • Regional Blood Flow
  • Tibia / blood supply*
  • Yohimbine / pharmacology

Substances

  • Receptors, Adrenergic, alpha
  • Yohimbine
  • Norepinephrine