Cold-Induced Changes in Arterial Sensitivity
Abstract
We studied the effects of cold on rabbits and pigs: (1) to determine how cold affects the smooth muscle sensitivity to receptor-mediated (NEPI - - Norepinephrine) or nonreceptor-mediated (KCL) (pigs only) agonist induction of in vitro vascular contraction; (2) to determine whether cold-induced vascular sensitivity to catecholamines exists in an intact hypothermic pig model; (3) to determine the effect of cortisol on the arterial smooth muscle contraction. The in vitro exposure of femoral arteries from rabbits and pigs to cold resulted in a progressive loss of sensitivity to agonist. Femoral arteries isolated from hypothermic pigs (core temp = 25 C for 2 hours) were no more sensitive to NEPI in vitro than arteries from normothermic animals. However, the in situ hind limb arterial bed of the hypothermic pig was ten times more sensitive to arterial injection of NEPI than the arterial bed of the normothermic pig. The sensitivity of porcine vascular smooth muscle to NEPI does not appear to be affected by cortisol. These data suggest that cold evokes an extravascular control (mechanisms not intrinsic to vascular tissue) over NEPI sensitivity. Moreover, these data suggest that the mechanism for control of cold-induced sensitivity to sympathetic neurotransmitter in the pig is different from the mechanism which operates in the rabbit.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1991
- Accession Number
- ADA239493
Entities
People
- Donald E. Roberts
- Stephen P. Bruttig
Organizations
- United States Army Research Institute of Environmental Medicine