摘要
目的：探讨老年人高血压哇巴因（Ouabain）抵抗现象机制及其与肾素、血管紧张素系统（RAS）的关系。方法：47例高血压病（EH）病人，分为老年EH组和非老年EH组，选择25名健康老年人作对照组。采用放射免疫分析法测定血浆肾素活性（PRA）、血管紧张素Ⅱ（AⅡ）、血浆内源性类地高辛物质（EDLS）浓度、EDLS与红细胞结合率（RBC－D％）；测定加Ouabain后红细胞内Na+浓度（[Na＋]i）变化，计算出Ouabain敏感Na+外流速度常数(oKos)，反映总的Na+泵活性；红细胞[Na+]i用火焰光度法测定。老年EH组和非老年EH组服硝苯啶治疗4周后复查。结果：老年EH组和非老年EH组RBC－D％、oKos下降，EDLS升高．但老年EH组RBC－D％、PRA、AII明显低于非老年EH组，血浆EDLS和oKos高于非老年EH组，Na+泵活性呈现Ouabain抵抗现象。在老年EH组中，AII与收缩压、年龄和RBC－D％呈负相关，PRA与EDLS呈负相关；在非老年EH组中，血压与EDI上呈负相关。降压治疗后，老年EH病人PRA、AII、Na+泵活性升高，EDLS有下降趋势；中年EH者仅Na+泵活性升高，EDLS有升高趋势，PRA、AII无显著变化。结论：老年EH病人EDLS与细胞膜亲合力下降，呈现Ouabain抵抗现象，通过影响钠代谢抑制PRA、AII分泌。钙拮抗剂降压治疗可部分改善这种异常。
Obiective:To study the mechanism of ouabain-resistant phenomenon and its relationship with renin-angiotensin system in elderly cases of essential hyPertension (EH)- Methods: 47 cases of essential hypertension Were divided according to their age into aged patierits (AP, 24) and nonaged patients (NAP, 23)groups. 25 aged healthy individuals served as normoterisive control. Plasma renin activity (PRA), angiotensin Ⅱ(AⅡ), endogenous digoxin-like substance. (EDLS) and the binding rate of EDLS with red blood cells (RBC-D%) wete determined with radioimmunoasay; The intra-erythrocytic Na+ concentration after 2 h incubatiOn with ouabain was datermined, and half of the value of intraerythrocytie Na+ concentration increase was considered as the rate constant of ouabain-sensitive Na+ efflux (K/h). Intraerythrocytic Na+concentration was measured with flame photometry. After the administration of nifedipine for 4 weeka, the hepertensive cases were examined again, Results: K and RBC-D% were significantly lower and the plasma level of EDLS signifitantly higher in AP and NAP groupt than in the control. Significantly higher plasma EDLS and K and lower RBC-D% and PRA were fouop in AP group than in NAP group. The fNa+ pump in the AP group showed an ouabain-resistant Phenomenori. All,the findings were negatively correlated to the age and systolic pressure of the patients and the changas of ;Rbo-D% and PRA were negativaly correlated to those of EDLS. In the NAP group, the changes of bloo4.,pressure were negatively correlated to thOse of EDLS. AftEr 4 weeks of nifedipine treatment, Na+ pump a(tivity, PRA and other Parameters were increased in the AP group but only Na+ pump activity was inPteased in'the NAP group. ConcIusiOns =Our findings indicated that the affinity of EDLS with cellular ...brkn. is de.theed in aged patients with EH, which is known as the ouabairi-resistant phenomenon. Ouabain resistance Jinhibits the secretidn of renin and anglotertsin throngh its effects on sodium metabolism and nifedipirie can partially correct this abnormality.
出处
《第三军医大学学报》
CAS
CSCD
北大核心
1999年第10期716-719,共4页
Journal of Third Military Medical University
基金
国家自然科学基金!39725013
