Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA.
Am J Physiol Regul Integr Comp Physiol. 2011 Dec;301(6):R1831-7. doi: 10.1152/ajpregu.00170.2011. Epub 2011 Sep 21.
We recently showed that a fixed volume (i.e., 40 ml) of saline infused into the venous circulation of an arterially occluded vascular bed increases muscle sympathetic nerve activity (MSNA) and blood pressure. In the present report, we hypothesized that the volume and rate of infusion would influence the magnitude of the sympathetic response. Blood pressure, heart rate, and MSNA were assessed in 13 young healthy subjects during forearm saline infusions (arrested circulation). The effects of different volumes of saline (i.e., 2%, 3%, 4%, or 5% forearm volume at 30 ml/min) and different rates of infusion (i.e., 5% forearm volume at 10, 20, or 30 ml/min) were evaluated. MSNA and blood pressure responses were linked with the infusion volume. Infusion of 5% of forearm volume evoked greater MSNA responses than did infusion of 2% of forearm volume (Δ11.6 ± 1.9 vs. Δ3.1 ± 1.8 bursts/min and Δ332 ± 105 vs. Δ38 ± 32 units/min, all P < 0.05). Moreover, greater MSNA responses were evoked by saline infusion at 30 ml/min than 10 ml/min (P < 0.05). Sonographic measurements confirmed that the saline infusions induced forearm venous distension. The results suggest that volume and rate of saline infusion are important factors in evoking sympathetic activation. We postulate that venous distension contributes to cardiovascular autonomic adjustment in humans.
我们最近表明，在动脉闭塞性血管床的静脉循环中输注固定体积（即 40 毫升）的生理盐水会增加肌肉交感神经活动（MSNA）和血压。在本报告中，我们假设输注量和输注速度会影响交感反应的幅度。在 13 名年轻健康受试者中评估了前臂生理盐水输注（停止循环）期间的血压、心率和 MSNA。评估了不同体积的生理盐水（即，30 ml/min 时占前臂体积的 2%、3%、4%或 5%）和不同的输注速度（即，10、20 或 30 ml/min 时占前臂体积的 5%）的影响。MSNA 和血压反应与输注量相关。输注 5%的前臂体积比输注 2%的前臂体积引起更大的 MSNA 反应（Δ11.6±1.9 对 Δ3.1±1.8 次/分钟和 Δ332±105 对 Δ38±32 单位/分钟，均 P<0.05）。此外，以 30 ml/min 的速度输注生理盐水比 10 ml/min 引起更大的 MSNA 反应（P<0.05）。超声测量证实生理盐水输注引起前臂静脉扩张。结果表明，输注量和速度是引起交感神经激活的重要因素。我们推测静脉扩张有助于人类心血管自主调节。
