Gender affects calf venous compliance at rest and during baroreceptor unloading in humans.
Gender affects calf venous compliance at rest and during baroreceptor unloading in humans.
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性别影响人类休息时和压力感受器卸载期间的小腿静脉顺应性。
DOI：
10.1152/ajpheart.00719.2003
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Ray,ChesterA
中科院分区：
文献类型：
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作者：
Monahan,KevinD;Ray,ChesterA
在立位应激期间，腿部静脉顺应性是外周静脉淤积的决定因素，因此高顺应性可能导致立位耐受性降低。我们测试了以下假设：1)压力感受器卸载过程中小腿静脉顺应性降低，2)女性小腿静脉顺应性高于男性。研究对象为12名男性(27±2岁)和12名女性(25±2岁)。测定小腿静脉顺应性的方法是将股静脉集合袖带充气至60 mm Hg 8min，然后以1 mm Hg/S至0 mm Hg的速度降低袖带压力。用收集袖带压力降低时压力-顺应性关系的斜率(顺应性=β1+2·β2·袖带压力)作为二次压力-容量关系[(Δ肢体体积)=β0+β1·(袖带压力)+β2·(袖带压力)2]的一阶导数，用于评估基础状态和单肢下体负压时的静脉顺应性。基线时，女性的小腿静脉顺应性比男性低48%(P<；0.001)，男性下降(Δ-25±8%；P<；0.05)，但女性(Δ1±11%)没有下降。节律性缺血握力(Δ6±9%)和冷加压试验(Δ-9±7%)不改变一组男性(n=6)的小腿静脉顺应性。这些数据表明，在低交感神经流出(即休息)和高交感神经流出(即下体负压)相关的情况下，性别对小腿静脉顺应性的影响。然而，他们不能解释立位耐受性的性别差异。
Leg venous compliance is a determinant of peripheral venous pooling during orthostatic stress such that high venous compliance could contribute to reduced orthostatic tolerance. We tested the hypotheses that1) calf venous compliance is reduced during baroreceptor unloading, and2) calf venous compliance is greater in women than men. Twelve men (27 ± 2 yr) and 12 women (25 ± 2 yr) were studied in the supine posture. Calf venous compliance was determined by inflating a thigh venous collecting cuff to 60 mmHg for 8 min and then decreasing cuff pressure at a rate of 1 mmHg/s to 0 mmHg. The slope 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 the reduction in collecting cuff pressure, was used to assess venous compliance at baseline and during one-legged lower body negative pressure (LBNP; —50 mmHg). At baseline, calf venous compliance was 48% lower (P< 0.001) in women than men and decreased in men (Δ—25 ± 8%;P< 0.05) but not women (Δ1 ± 11%) during LBNP. Rhythmic ischemic handgrip (Δ6 ± 9%) and cold pressor testing (Δ—9 ± 7%) did not alter calf venous compliance in a subgroup of men (n= 6). These data indicate gender-dependent effects on calf venous compliance under conditions associated with low sympathetic outflow (i.e., rest) and high sympathetic outflow (i.e., LBNP). However, they cannot explain gender-associated differences in orthostatic tolerance.