Miller J A
Department of Medicine, University of Toronto, Ontario, Canada.
Am J Physiol. 1995 Aug;269(2 Pt 2):R380-8. doi: 10.1152/ajpregu.1995.269.2.R380.
Uncomplicated insulin-dependent diabetes mellitus (IDDM) is associated with a suppressed reflex response to sympathetic nervous system (SNS) stimulation and an enhanced pressor response to catecholamines. This study examined the SNS in subjects with IDDM (duration < 5 yr, n = 9) to determine the responsible mechanism within the cardiopulmonary baroreflex arc and the role played by extracellular fluid volume (ECFV) expansion. The reflex arc was tested by examining the plasma norepinephrine (PNE) and forearm vascular (FVR) responses to 60 min of cardiopulmonary baroreceptor unloading by lower body negative pressure (LBNP) at -15 mmHg. The effector limb was tested by measuring the PNE, FVR, and mean arterial pressure (MAP) response to the cold pressor test (CPT). The postganglionic neuroeffector junction was tested by measuring the venoconstrictive response to local norepinephrine infusion. ECFV was varied by altering dietary sodium. In IDDM subjects on a 250 mmol sodium diet, PNE and FVR responses to LBNP (delta PNE = 0.15 +/- 0.05; delta FVR = 4.3 +/- 1.2) were attenuated compared with controls (delta PNE = 0.36 +/- 0.23; delta FVR = 11.56 +/- 2.72). MAP and FVR responses to the CPT were intact (delta MAP = 9.74 +/- 1.9; delta FVR = 7.02 +/- 3.11) compared with controls (delta MAP = 10.74 +/- 2.69; delta FVR = 8.26 +/- 2.94), but the PNE response was attenuated. The peripheral vasculature was hyperresponsive to norepinephrine infusion in IDDM subjects [mean effective dose (ED50) = 57 +/- 10 ng/min] compared with controls (ED50 = 133 +/- 30 ng/min). Sodium restriction (20 mmol/day) normalized the FVR response to LBNP and the venous response to norepinephrine infusion. The PNE response both to LBNP and the CPT remained attenuated.(ABSTRACT TRUNCATED AT 250 WORDS)
单纯胰岛素依赖型糖尿病（IDDM）与交感神经系统（SNS）刺激下的反射反应受抑制以及对儿茶酚胺的升压反应增强有关。本研究对IDDM患者（病程<5年，n = 9）的SNS进行了检测，以确定心肺压力反射弧内的相关机制以及细胞外液量（ECFV）扩张所起的作用。通过检测血浆去甲肾上腺素（PNE）和前臂血管阻力（FVR）对-15 mmHg下体负压（LBNP）导致的60分钟心肺压力感受器卸载的反应来测试反射弧。通过测量对冷加压试验（CPT）的PNE、FVR和平均动脉压（MAP）反应来测试效应肢体。通过测量对局部去甲肾上腺素输注的静脉收缩反应来测试节后神经效应器连接点。通过改变饮食中的钠来改变ECFV。在摄入250 mmol钠饮食的IDDM患者中，与对照组相比，对LBNP的PNE和FVR反应（ΔPNE = 0.15±0.05；ΔFVR = 4.3±1.2）减弱（对照组：ΔPNE = 0.36±0.23；ΔFVR = 11.56±2.72）。与对照组相比（ΔMAP = 10.74±2.69；ΔFVR = 8.26±2.94），对CPT的MAP和FVR反应完整（ΔMAP = 9.74±1.9；ΔFVR = 7.02±3.11），但PNE反应减弱。与对照组（ED50 = 133±30 ng/min）相比，IDDM患者的外周血管对去甲肾上腺素输注反应过度[平均有效剂量（ED50）= 57±10 ng/min]。钠限制（20 mmol/天）使对LBNP的FVR反应和对去甲肾上腺素输注的静脉反应恢复正常。对LBNP和CPT的PNE反应仍然减弱。（摘要截短于250字）
