Adrenergic mechanisms do not contribute to age-related decreases in calf venous compliance.
Adrenergic mechanisms do not contribute to age-related decreases in calf venous compliance.
复制标题
肾上腺素能机制不会导致与年龄相关的小腿静脉顺应性下降。
DOI：
10.1152/japplphysiol.00930.2010
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Monahan,KevinD
中科院分区：
文献类型：
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作者：
Sielatycki,JohnA;Shamimi-Noori,Saum;Pfeiffer,MichaelP;Monahan,KevinD
四肢静脉顺应性随着年龄的增长而降低，即使是健康人也是如此。为了验证肾上腺素能机制导致肢体静脉顺应性随年龄下降的假设，我们测量了 8 名年轻健康男性（27 ± 1 岁，平均值 ± SE）和 8 名老年健康男性（67 ± 2 岁）在急性全身 α 和 β 肾上腺素能阻断之前和期间的小腿静脉顺应性。通过将大腿收集袖带充气至 60 mmHg 持续 8 分钟，然后将其降低（1 mmHg/s）至 0 mmHg，同时用应变仪对小腿体积进行索引，确定仰卧受试者的小腿静脉顺应性。压力-顺应性关系（顺应性= β1+ 2·β2·袖带压力）的斜率（·10−3）是袖带压力降低过程中二次压力-容积关系[（Δ肢体体积）= β0+ β1·（袖带压力）+ β2·（袖带压力）2]的一阶导数，用于量化小腿静脉顺应性。与肾上腺素能阻断前的年轻男性相比，老年人的小腿静脉顺应性降低约 30%（P<0.01）。对于肾上腺素能阻断，年轻男性（阻断前和阻断期间分别为−2.62 ± 0.14 和−2.29 ± 0.18 ml·dl−1·mmHg−1）或老年男性（−1.78 ± 0.27 和−1.68 ± 0.21 ml·dl−1·mmHg−1）的小腿静脉顺应性并未增加。此外，在肾上腺素能阻断期间，在肾上腺素能阻断之前观察到的年轻男性和老年男性之间小腿静脉顺应性的差异持续存在。总的来说，这些数据强烈表明，肾上腺素能机制既不会直接抑制年轻或老年男性的小腿静脉顺应性，也不会导致健康男性中与年龄相关的小腿静脉顺应性降低。
Limb venous compliance decreases with advancing age, even in healthy humans. To test the hypothesis that adrenergic mechanisms contribute to age-associated reductions in limb venous compliance, we measured calf venous compliance before and during acute systemic α- and β-adrenergic blockade in eight young (27 ± 1 yr old, mean ± SE) and eight older healthy men (67 ± 2 yr old). Calf venous compliance was determined in supine subjects by inflating a thigh-collecting cuff to 60 mmHg for 8 min and then decreasing it (1 mmHg/s) to 0 mmHg while calf volume was indexed with a strain gauge. The slope (·10−3) of the pressure-compliance relation (compliance= β1+ 2·β2·cuff pressure), which is the first derivative of the quadratic pressure-volume relation [(Δlimb volume) = β0+ β1·(cuff pressure) + β2·(cuff pressure)2] during reductions in cuff pressure, was used to quantify calf venous compliance. Calf venous compliance was ∼30% lower (P< 0.01) in older compared with young men before adrenergic blockade. In response to adrenergic blockade calf venous compliance did not increase in young (−2.62 ± 0.14 and −2.29 ± 0.18 ml·dl−1·mmHg−1, before and during blockade, respectively) or older men (−1.78 ± 0.27 and −1.68 ± 0.21 ml·dl−1·mmHg−1). Moreover, during adrenergic blockade differences in calf venous compliance between young and older men observed before adrenergic blockade persisted. Collectively, these data strongly suggest that adrenergic mechanisms neither directly restrain calf venous compliance in young or older men nor do they contribute to age-associated reductions in calf venous compliance in healthy men.