Effects of aging on adipose resistance artery vasoconstriction: possible implications for orthostatic blood pressure regulation.
The purpose of this investigation was to determine mean arterial pressure (MAP) and regional vascular conductance responses in young and aged Fisher-344 rats during orthostatic stress, i.e., 70 degrees head-up tilt (HUT). Both groups demonstrated directionally different changes in MAP during HUT (young, 7% increase; aged, 7% decrease). Vascular conductance during HUT in young rats decreased in most tissues but largely remained unchanged in the aged animals. Based on the higher vascular conductance of white adipose tissue from aged rats during HUT, resistance arteries from white visceral fat were isolated and studied in vitro. There was diminished maximal vasoconstriction to phenylephrine and norepinephrine (NE: young, 42 +/- 5%; old, 18 +/- 6%) in adipose resistance arteries from aged rats. These results demonstrate that aging reduces the ability to maintain MAP during orthostatic stress, and this is associated with a diminished vasoconstriction of adipose resistance arteries.
Ramsey
Michael W
MW
Department of Kinesiology, Leisure, and Sport Sciences, East Tennessee State University, Johnson City, Tennessee, USA.
Behnke
Bradley J
BJ
Prisby
Rhonda D
RD
Delp
Michael D
MD
D000222:Adaptation, Physiological; D052436:Adipose Tissue, White / Q000098:blood supply* / Q000187:drug effects; D000367:Age Factors; D000375:Aging; D000818:Animals; D001158:Arteries / Q000503:physiopathology; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000187:drug effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate; D007024:Hypotension, Orthostatic / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011187:Posture; D051381:Rats; D011916:Rats, Inbred F344; D012039:Regional Blood Flow; D014655:Vascular Resistance / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D009638:Norepinephrine