Vaz M, Cox H S, Kaye D M, Turner A G, Jennings G L, Esler M D
Alfred Baker Medical Unit, Baker Medical Research Institute, Victoria, Australia.
J Auton Nerv Syst. 1995 Dec 5;56(1-2):97-104. doi: 10.1016/0165-1838(95)00063-4.
The use of the plasma noradrenaline (NA) concentration as an index of sympathetic nervous system (SNS) activity in the postprandial state is associated with several problems: (i) It does not take into account the contribution of alterations in clearance to the plasma NA level, (ii) when antecubital venous blood is sampled, it reflects regional forearm rather than whole body SNS activity and (iii) no insight is gained into the regional pattern of SNS activation. These potential confounders were addressed in this study performed in 17 healthy young men. The validity of plasma NA measurements in assessing postprandial changes in sympathetic nervous activation was evaluated in relation to that of whole body and regional plasma NA spillover, derived using isotope dilution methodology. Plasma clearance of NA is significantly altered following a meal, with a transient elevation in the early postprandial phase which may lead to an underestimation of SNS activation when assessed from arterial plasma NA levels. Forearm plasma NA spillover increases postprandially, such that despite significant postprandial elevations in arterial plasma NA, the plasma arterial contribution to antecubital venous plasma NA levels is maintained at less than 40%, the rest being derived locally from the forearm. This makes venous plasma samples unsuitable for the assessment of SNS activation in organs and vascular sites distant from the sampling site. The kidneys and skeletal muscle are the major regional sites of postprandial sympathetic nervous activation, while cardiac plasma NE spillover is unaltered postprandially. This regional pattern of SNS activation postprandially must be taken into account when relating increments in plasma NA levels to specific physiological events.
将餐后状态下血浆去甲肾上腺素（NA）浓度作为交感神经系统（SNS）活动指标存在几个问题：（i）它没有考虑清除率变化对血浆NA水平的影响；（ii）采集肘前静脉血时，它反映的是局部前臂而非全身的SNS活动；（iii）无法了解SNS激活的区域模式。本研究在17名健康年轻男性中进行，解决了这些潜在的混杂因素。使用同位素稀释法得出全身和局部血浆NA溢出率，以此评估血浆NA测量在评估餐后交感神经激活变化方面的有效性。进食后NA的血浆清除率显著改变，餐后早期会短暂升高，这可能导致从动脉血浆NA水平评估SNS激活时被低估。餐后前臂血浆NA溢出增加，因此尽管动脉血浆NA餐后显著升高，但动脉血浆对肘前静脉血浆NA水平的贡献维持在40%以下，其余部分来自前臂局部。这使得静脉血浆样本不适用于评估远离采样部位的器官和血管部位的SNS激活。肾脏和骨骼肌是餐后交感神经激活的主要局部部位，而餐后心脏血浆NE溢出未改变。在将血浆NA水平的升高与特定生理事件联系起来时，必须考虑餐后SNS激活的这种区域模式。
