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Effects of smooth muscle tone on venous hemodynamic function in young and older adults
Author(s) -
Young Colin Neal,
Stillabower Michael,
Farquhar William
Publication year - 2006
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.20.5.a1404-b
Venous compliance is lower in older adults compared to younger adults. It is possible that alterations in venous smooth muscle tone may contribute to the age‐related differences in venous compliance. Purpose To determine the effects of sympathetic activation (cold pressor test; CP) and endothelium independent decreases in smooth muscle tone (sublingual nitroglycerin; NTG) on venous compliance in young and older adults. Methods Forearm venous compliance was measured in 23 young (22 ± 4) and 8 old (64 ± 3) supine subjects by inflating a venous occlusion cuff on the upper arm to 60 mmHg for 8 min and then releasing the pressure at a rate of 1 mmHg/s to 0 mmHg. Venous compliance was assessed at baseline, during the CP test, and following NTG administration. All P‐V relationships were modeled with a quadratic regression equation and β 1 and β 2 were used as indices of venous compliance. A repeated measures ANOVA was used to determine the effect of the trial on venous compliance. Results Forearm regression parameters, β 1 and β 2 were significantly less in older adults at baseline (young vs. old, respectively; β 1: 0.0959 vs. 0.0724; p < 0.05, β 2: −0.0008 vs. −0.0006; p < 0.05). Venous compliance was not effected by the CP test or sublingual NTG in either group. Conclusion Preliminary data suggest that forearm venous compliance is lower in older adults compared to young. However, this difference probably cannot be explained by alterations in smooth muscle tone. Supported by NIH grant R03 AG23836‐01