Bevegård S, Castenfors J, Lindblad L E
Acta Physiol Scand. 1977 Feb;99(2):237-45. doi: 10.1111/j.1748-1716.1977.tb10375.x.
In 8 healthy subjects the pressure around the lower body was changed to 40 mmHg above (LBPP) and below (LBNP) atmospheric, thereby altering the amount of blood pooled in the lower body. Heart rate, intraarterial blood pressure, central venous pressure, cardiac output (dye dilution technique) and forearm blood flow (venous occlusion plethysmography) were measured. Plasma renin activity was determined with a radioimmunological method. 6 subjects maintained a relative circulatory steady state during LBNP. LBNP caused significant decrease in central venous pressure (CVP), stroke volume and cardiac output (Q) with an unchanged mean arterial pressure (MAP). Heart rate (HR) increased significantly. Calculated total peripheral vascular resistance (TPVR) and regional vascular resistance (RVR) in the forearm were significantly increased when measured 5-9 min after the onset of LBNP, whereas plasma renin activity (PRA) showed a definite increase only after 19 min of LBNP stimulation. No correlation was found between the changes in PRA and TPVR or RVR. Increasing the pressure around the lower body (LBPP) resulted in a slight but significant increase in MAP as well as a significant but transient increase in CVP. No significant changes were found in HR, Q or TPVR. In the forearm a decrease in RVR was demonstrated. PRA was not significantly changed. The results demonstrate that peripheral vascular resistance and PRA are both influenced by changes in blood volume distribution, possibly elicited via intrathoracic receptors sensitive to changes in central blood volume and/or CVP. The results also suggest that PRA does not play any significant part in the vasoconstriction during LBNP stimulation.
在8名健康受试者中，将下半身周围的压力改变为高于（下肢正压，LBPP）和低于（下肢负压，LBNP）大气压40 mmHg，从而改变下半身的血液淤积量。测量了心率、动脉内血压、中心静脉压、心输出量（染料稀释技术）和前臂血流量（静脉阻断体积描记法）。采用放射免疫法测定血浆肾素活性。6名受试者在下肢负压期间维持相对循环稳态。下肢负压导致中心静脉压（CVP）、每搏输出量和心输出量（Q）显著降低，而平均动脉压（MAP）不变。心率（HR）显著增加。在下肢负压开始后5 - 9分钟测量时，计算得出的总外周血管阻力（TPVR）和前臂局部血管阻力（RVR）显著增加，而血浆肾素活性（PRA）仅在下肢负压刺激19分钟后才出现明显增加。未发现PRA变化与TPVR或RVR之间存在相关性。增加下半身周围的压力（LBPP）导致MAP略有但显著升高，以及CVP显著但短暂升高。HR、Q或TPVR未发现显著变化。在前臂，RVR降低。PRA无显著变化。结果表明，外周血管阻力和PRA均受血容量分布变化的影响，可能是通过对中心血容量和/或CVP变化敏感的胸内感受器引发的。结果还表明，PRA在下肢负压刺激期间的血管收缩中不起任何重要作用。
