Schächinger Hartmut, Port Johannes, Brody Stuart, Linder Lilly, Wilhelm Frank H, Huber Peter R, Cox Daniel, Keller Ulrich
Department of Internal Medicine, Clinical Research Center and Division of Psychosomatic Medicine, University Hospital, 4031 Basel, Switzerland.
Clin Sci (Lond). 2004 Jun;106(6):583-8. doi: 10.1042/CS20030337.
Despite causing sympathetic activation, prolonged hypoglycaemia produces little change in HR (heart rate) in healthy young adults. One explanation could be concurrent parasympathetic activation, resulting in unchanged net effects of autonomic influences. In the present study, hypoglycaemic (2.7 mmol/l) and normoglycaemic (4.7 mmol/l) hyperinsulinaemic clamp studies were performed after normoglycaemic baseline clamp periods with 15 healthy volunteers (seven male; mean age, 27 years) on two occasions in a randomized single-blind cross-over design. Non-invasive indices of cardiac autonomic activity and hormones were measured at baseline and 1 h after the beginning of hypoglycaemia or control normoglycaemia. Plasma insulin levels and mean HR were similar during both conditions. During hypoglycaemia, there was a 485% increase in plasma adrenaline (epinephrine). A shortening of the pre-ejection period by 45% suggested strong sympathetic cardiac activation. High-frequency (0.15-0.45 Hz) HRV (HR variability) increased, indicating a concomitant increase in parasympathetic tone. Thus, during hypoglycaemia-induced sympathetic cardiac activation in healthy adults, parasympathetic mechanisms are involved in stabilizing mean HR.
尽管低血糖会引起交感神经激活，但在健康的年轻成年人中，长时间低血糖对心率（HR）的影响很小。一种解释可能是同时存在副交感神经激活，导致自主神经影响的净效应不变。在本研究中，对15名健康志愿者（7名男性；平均年龄27岁）进行了两次随机单盲交叉设计的实验，在正常血糖基线钳夹期后分别进行低血糖（2.7 mmol/l）和正常血糖（4.7 mmol/l）高胰岛素钳夹研究。在基线以及低血糖或对照正常血糖开始后1小时测量心脏自主神经活动和激素的非侵入性指标。两种情况下血浆胰岛素水平和平均心率相似。在低血糖期间，血浆肾上腺素（肾上腺素）增加了485%。射血前期缩短45%表明交感神经对心脏有强烈激活。高频（0.15 - 0.45 Hz）心率变异性（HRV）增加，表明副交感神经张力同时增加。因此，在健康成年人低血糖诱导的交感神经心脏激活过程中，副交感神经机制参与稳定平均心率。
