Effects of salt loading on the fractional volume of atria-specific granules in Dahl salt-sensitive and salt-resistant rats.
Effects of salt loading on the fractional volume of atria-specific granules in Dahl salt-sensitive and salt-resistant rats.
复制标题
盐负荷对达尔盐敏感和耐盐大鼠心房特异性颗粒体积分数的影响。
DOI：
10.1002/ar.1092180210
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Howell,A
中科院分区：
文献类型：
--
作者：
Hansen,JT;Haywood,JR;Howell,A
已知心脏心房在血容量稳态中起作用，分泌一种肽，诱导有效的钠尿和利尿。这种肽是心房利钠因子（ANF），其主要储存部位是心房细胞中的心房特异性颗粒。由于盐负荷导致ANF循环水平升高，我们的目的是确定Dahl大鼠心肌细胞中心房特异性颗粒群是否会相应减少。为此，在Dahl盐高血压模型中通过超微结构形态测定分析确定心房特异性颗粒的体积分数。在处死前喂食低盐（0.4%）或高盐（8%）饲料12周的Dahl耐盐（DR）和盐敏感（DS）大鼠的右心房上进行该分析。与高盐饮食大鼠相比，低盐饮食大鼠的血浆钠水平和渗透压显著降低，平均动脉血压显著降低。盐负荷DR（P<0.01）和DS（P<0.025）大鼠的心房特异性颗粒体积分数显著低于各自的低盐对照组。心房颗粒的这种显著减少对应于盐负荷大鼠中心房ANF储存的报告减少，并提供了生化研究的形态学验证。此外，这些结果，结合越来越多的生理数据，支持假设的作用，心钠素在调节水电解质平衡，这可能在心血管病理生理状态相关的高血压中发挥重要作用。
The cardiac atria are known to play a role in blood volume homeostasis, secreting a peptide that induces a potent natriuresis and diuresis. This peptide is atrial natriuretic factor (ANF), and its primary site of storage is within atria‐specific granules found in atrial cardiocytes.Since salt loading results in an increase in circulating levels of ANF, our aim was to determine if the atria‐specific granule population in the cardiocytes of Dahl rats would decrease accordingly. To this end, the fractional volume of the atria‐specific granules was determined by ultrastructural morphometric analysis in the Dahl salt model of hypertension. This analysis was performed on the right atria of Dahl salt‐resistant (DR) and salt‐sensitive (DS) rats fed either a low‐salt (0.4%) or high‐salt (8%) diet for 12 weeks prior to sacrifice. DR and DS rats fed a low‐salt diet had significantly reduced plasma sodium levels and osmolalities, and a significantly lower mean arterial blood pressure than did rats fed a high‐salt diet. The fractional volume of atria‐specific granules was significantly lower in salt‐loaded DR (P<0.01) and DS (P<0.025) rats than in their respective low‐salt controls. This significant decrease in atrial granules corresponds to the reported decrease in the storage of atrial ANF in salt‐loaded rats, and provides a morphological verification of the biochemical studies. Moreover, these results, in combination with a growing body of physiological data, lend support to the hypothesized role of ANF in the regulation of water–electrolyte balance, which may play an important role in cardiovascular pathophysiological states related to hypertension.