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Rat aortic vasoreactivity is altered by old age and hindlimb unloading
M D Delp1, M Brown, M H Laughlin
1Department of Surgery, Medical College of Pennsylvania, Pittsburgh 15212, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|June 1, 1995
Summary
Physical inactivity and aging both impair vascular reactivity, similar to bed rest effects. This study in rats shows reduced blood vessel function in unloaded and aged animals, impacting cardiovascular health.
Area of Science:
- Cardiovascular Physiology
- Aging Research
- Vascular Biology
Background:
- Prolonged bed rest in young adults causes cardiovascular changes like orthostatic intolerance.
- Similar cardiovascular alterations are observed with advanced age.
- These changes may stem from altered peripheral vascular reactivity.
Purpose of the Study:
- To investigate if physical inactivity in rats mimics age-related vascular changes.
- To determine if inactivity exacerbates age-related vascular dysfunction.
- To examine age and inactivity effects on vasomotor responsiveness.
Main Methods:
- Used rat hindlimb unloading as a model for physical inactivity.
- Examined responses to vasoactive compounds in isolated rat abdominal aortic rings in vitro.
- Measured maximal contractile force and vasorelaxation to vasoconstrictors and vasodilators.
Main Results:
- Maximal contractile force to KCl, norepinephrine, and arginine vasopressin was reduced in young hindlimb-unloaded, old control, and old hindlimb-unloaded rats.
- Sensitivity to KCl was enhanced in unloaded and old rats.
- Vasorelaxation to acetylcholine and sodium nitroprusside was impaired in unloaded and old rats.
Conclusions:
- Hindlimb unloading in rats induces vascular reactivity changes similar to aging.
- Physical inactivity and aging independently and potentially synergistically impair vascular function.
- These findings highlight the detrimental cardiovascular effects of inactivity and aging on vascular tone.