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Aging Diminishes Adrenergic Vasoconstriction in Adipose Tissue Resistance Arteries
Author(s) -
Behnke Brad J,
Delp Michael D
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a481-c
Subject(s) - vasoconstriction , adipose tissue , adrenergic , vasodilation , cardiology , medicine , receptor
Orthostatic hypotension is a common problem among the elderly, but whether this is due, in part, to diminished adipose vasoconstriction remains unclear. PURPOSE: Based upon a higher adipose tissue vascular conductance in aged animals during an orthostatic stress (70° head‐up tilt), we tested the hypothesis that there would be a diminished adrenergic vasoconstriction in resistance vessels isolated from adipose tissue in aged versus young rats. METHODS: Resistance arteries from abdominal adipose tissue in young (4–6 mo; n = 7) and aged (24–26 mo; n = 7) Fisher‐344 rats were isolated, cannulated, and the magnitude of vasoconstriction to norepinephrine (NE) and phenylephrine (PE) was studied in vitro. RESULTS: In the aged vessels there was a diminished vasoconstriction to NE and PE (P<0.05), whereas a robust vasoconstriction was present in adipose resistance arteries from young rats (young, 42 ± 5 % vs. aged, 18 ± 6 % vasoconstriction to NE). DISCUSSION: Given aged rats have a greater percent of cardiac output to adipose tissue compared to adult rats, a reduced vasoconstriction in resistance vessels from this vascular bed could have severe ramifications upon the ability to decrease peripheral vascular conductance during orthostatic challenges and exercise in the aged population. Supported by NASA NCC2‐1166 and NIH F32 AG25622.