Speth R C, Singh R, Smeby R R, Ferrario C M, Husain A
Neuroendocrinology. 1984 May;38(5):387-92. doi: 10.1159/000123922.
Male Sprague-Dawley rats were maintained on either a normal or low-sodium diet for 5 weeks to examine whether dietary sodium restriction alters angiotensin II (Ang II) receptors. The receptor sites in the hypothalamus-thalamus-septum (H-T-S) region of the brain, the adrenal glands and bladder visceral smooth muscle were measured by saturation isotherm binding assays using 125I-Ang II. Compared to control rats, the low-sodium diet group showed a smaller weight gain, reduced water intake, elevated hematocrit, and decreased urinary sodium concentration. In addition, sodium-depleted rats had a 10-fold elevation in plasma renin activity. However, neither binding affinity of 125I-Ang II to the brain H-T-S region nor its density was significantly different between the two groups. In contrast, both the 125I-Ang II binding density and dissociation constant in the adrenal gland were significantly elevated, while the binding density of 125-I-Ang II in the bladder smooth muscle was significantly decreased in the sodium-restricted group. These results suggest that dietary sodium depletion does not alter Ang II receptors in the rat brain areas wherein Ang II exerts the majority of its central actions.
将雄性斯普拉格-道利大鼠分别给予正常饮食或低钠饮食5周，以研究饮食中钠限制是否会改变血管紧张素II（Ang II）受体。使用125I-Ang II通过饱和等温线结合试验测量大脑下丘脑-丘脑-隔区（H-T-S）、肾上腺和膀胱内脏平滑肌中的受体位点。与对照大鼠相比，低钠饮食组体重增加较小、饮水量减少、血细胞比容升高且尿钠浓度降低。此外，缺钠大鼠的血浆肾素活性升高了10倍。然而，两组之间125I-Ang II与大脑H-T-S区的结合亲和力及其密度均无显著差异。相反，肾上腺中125I-Ang II的结合密度和解离常数均显著升高，而在钠限制组中，膀胱平滑肌中125-I-Ang II的结合密度显著降低。这些结果表明，饮食中钠缺乏不会改变大鼠脑区中Ang II发挥其大部分中枢作用的Ang II受体。
