Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York 10962, USA.
J Neuropathol Exp Neurol. 2011 Feb;70(2):151-6. doi: 10.1097/NEN.0b013e318208fc5d.
The median eminence of the hypothalamus is an important conduit by which neurosecretory hormones from hypothalamic nuclei are delivered to the pars nervosa (neural lobe) of the pituitary en route to the bloodstream. Dilutional hyponatremia was produced in adult rats to determine the effect on the morphology of the median eminence of the hypothalamus. Hyponatremia was caused by reducing electrolyte and organic osmolyte reserves to block the excretion of water through delivery of the nephrotoxin mercuric chloride (HgCl2). Histological examination of the brain 1 day after a hyponatremic insult revealed vacuolation within the median eminence of the hypothalamus. No other lesions were found in other parts of the brain after hyponatremia. The hyponatremic lesion consisted of a band of closely packed vacuoles that crossed the floor of the third ventricle. Vacuoles associated with hyponatremia were predominantly in the subependymal, fiber, reticular, and palisade layers of the median eminence. Vacuolation was not observed in the tanycyte layer of the median eminence. This study indicates that the median eminence is a potentially vulnerable site in human hyponatremic conditions that should be evaluated further in relevant animal models.
下丘脑的正中隆起是一个重要的通道，通过它，下丘脑核内的神经分泌激素被运送到垂体的神经部（神经垂体），然后进入血液。本研究通过制作成人大鼠稀释性低钠血症模型，观察低钠血症对下丘脑正中隆起形态的影响。通过减少电解质和有机渗透溶质储备来阻断肾毒素氯化汞（HgCl2）的排泄，从而导致低钠血症。低钠血症后 1 天对大脑进行组织学检查，发现下丘脑正中隆起内有空泡形成。低钠血症后，在大脑的其他部位没有发现其他病变。低钠血症病变由穿过第三脑室底部的紧密排列的空泡带组成。与低钠血症相关的空泡主要位于正中隆起的室管膜下、纤维、网状和栅栏层。在正中隆起的粟状体细胞层中没有观察到空泡化。本研究表明，正中隆起是人低钠血症状态下的一个潜在脆弱部位，在相关的动物模型中应进一步评估。
