Oparil S, Chen Y F, Jin H K, Yang R H, Wyss J M
Department of Medicine, University of Alabama, Birmingham 35294.
Am J Clin Nutr. 1991 Jul;54(1 Suppl):227S-236S. doi: 10.1093/ajcn/54.1.227S.
NaCl-sensitive spontaneously hypertensive rats (SHR-S) were used to test the hypotheses that dietary Ca2+ supplementation 1) prevents NaCl-sensitive hypertension via a sympatholytic mechanism, and 2) increases diuretic and natriuretic responses to acute volume loading. SHR-S and control WKY rats were begun on one of four diets at age 8 wk: control, high NaCl, high Ca2+, or high NaCl and high Ca2+. In SHR-S, dietary Ca2+ supplementation prevented the NaCl-induced increases in blood pressure and plasma norepinephrine concentrations, the reductions in anterior hypothalamic norepinephrine stores and turnover, and the secondary increases in alpha 2 adrenoceptor number. Thus, Ca2+ prevented NaCl-sensitive hypertension in SHR-S by increasing noradrenergic input to the anterior hypothalamus. High-NaCl-fed SHR-S had impaired diuretic and natriuretic responses to an isotonic volume load; Ca2+ enhanced the ability of these animals to adjust fluid volume rapidly via diuresis and natriuresis. This alteration in renal function may contribute to the hypotensive effect of a high Ca2+ diet in NaCl-sensitive hypertension.
使用盐敏感型自发性高血压大鼠（SHR-S）来检验以下假设：膳食补充钙2+ 1）通过抗交感神经机制预防盐敏感型高血压，以及2）增强对急性容量负荷的利尿和排钠反应。SHR-S和对照WKY大鼠在8周龄时开始采用四种饮食之一：对照饮食、高盐饮食、高钙饮食或高盐高钙饮食。在SHR-S中，膳食补充钙2+可预防盐诱导的血压和血浆去甲肾上腺素浓度升高、下丘脑前部去甲肾上腺素储存和周转率降低以及α2肾上腺素能受体数量的继发性增加。因此，钙2+通过增加去甲肾上腺素能输入到下丘脑前部来预防SHR-S中的盐敏感型高血压。高盐喂养的SHR-S对等渗容量负荷的利尿和排钠反应受损；钙2+增强了这些动物通过利尿和排钠快速调节液体容量的能力。肾功能的这种改变可能有助于高钙饮食对盐敏感型高血压的降压作用。
