不同反复体位改变试验下人体心血管调节机制的研究

Research on Cardiovascular Regulation Mechanism of Human under Different Repeated Body Position Change Tests

目的通过比较血容量及容量调节性激素的变化,探讨不同反复体位改变试验下人体心血管调节差异的生理学机制。方法30名健康男性随机分组进行头低位(head-down tilt,HDT)/头高位(head-up tilt,HUT)与平卧位(supine,SUP)/头高位(head-up tilt,HUT)反复体位改变试验,试验结束后分别进行立位/头低位检查,取每个体位第2分钟时的红细胞压积(HCT)、血浆肾素活性(PRA)、血管紧张素Ⅱ(AⅡ)、醛固酮(ALD)、抗利尿激素(ADH)、心钠素(ANP)进行分析。结果与训练前比较,HCT在HDT/HUT训练后,在立位检查的SUP与HUT阶段与头低位检查的SUP阶段均显著升高(P<0.05);PRA在SUP/HUT训练后,在立位检查的SUP阶段与头低位检查的SUP与HDT阶段均显著升高(P<0.05);ANP在HDT/HUT模式训练后,在立位检查的HUT阶段较SUP阶段上升边缘显著(P=0.062)。结论 HDT/HUT训练使人体发生血液浓缩,而SUP/HUT训练通过重置压力感受性反射使人体产生不同的心血管调节反应。

Objective To explore the physiological mechanism of human cardiovascular regulation under different repeated body position change tests by comparing the changes of blood volume and volume regulating hormones.Methods Thirty healthy males were randomized to perform HDT/HUT(headdown tilt/head-up tilt)or SUP/HUT(supine/head-up tilt)tests.At the end of each test,orthostatic and head-down examination were executed,and the hematocrit(HCT),plasma renin activity(PRA),angiotensinⅡ(AⅡ),aldosterone(ALD),antidiuretic hormone(ADH)and atrial natriuretic peptide(ANP)were analyzed at 2 nd minute of each body position.Results HCT increased significantly after the HDT/HUT test in the SUP and HUT phases of the orthostatic examination and the SUP phase of the head-down examination as compared with the pre-training(P<0.05);PRA decreased significantly after the SUP/HUT test in the SUP phase of the orthostatic examination,and both the SUP and HDT phases of the head-down examination as compared with the pre-training(P<0.05);ANP increased marginal significantly(P=0.062)in the HUT phase as compared with the SUP phase of the orthostatic examination after the HDT/HUT test.Conclusion The cardiovascular regulation response of two modes of repeated position change tests may involve different physiological mechanisms:the HDT/HUT repeated position change test concentrated the blood of human body and the SUP/HUT repeated position change test shifted the baroreceptor reflex control by resetting the baroreflex of human body.