The blood–brain barrier regulates the transport of molecules that convey global energetic status to the feeding circuitry within the hypothalamus. Capillaries within the median eminence (ME) and tight junctions between tanycytes lining the third ventricle (3V) are critical components of this barrier. Herein, we tested the hypothesis that altering the plane of nutrition results in the structural reorganization of tanycytes, tight junctions, and capillary structure within the medial basal hypothalamus. Proopiomelanocortin (POMC) neuronal content within the arcuate nucleus of the hypothalamus (ARC) was also assessed to test whether reduced nutritional status improved access of nutrients to the ARC, while decreasing the access of nutrients of overfed animals. Multiparous, nongestating ewes were stratified by weight and randomly assigned to dietary treatments offered for 75 d: 200% of dietary recommendations (overfed), 100% of dietary recommendations (control), or 60% of dietary recommendations (underfed). The number of POMC-expressing neurons within the ARC was increased (P ≤ 0.002) in underfed ewes. Overfeeding increased (P ≤ 0.01) tanycyte cellular process penetration and density compared with control and underfeeding as assessed using vimentin immunostaining. Immunostaining of tight junctions along the wall of the 3V did not differ (P = 0.32) between treatments. No differences were observed in capillary density (P = 0.21) or classification (P ≥ 0.47) within the ME. These results implicate that changes within the satiety center and morphology of tanycytes within the ARC occur as an adaptation to nutrient availability.

血脑屏障调节将整体能量状态传递到下丘脑内进食回路的分子的运输。中位隆起（ME）内的毛细血管以及位于第三脑室（3V）内的单核细胞之间的紧密连接是该屏障的关键组成部分。在本文中，我们检验了以下假设：改变营养平面会导致内侧基底下丘脑内的单核细胞，紧密连接和毛细血管结构的结构重组。还评估了下丘脑（ARC）弓状核内的Proopiomelanocortin（POMC）神经元含量，以测试营养状况的降低是否能改善营养物质对ARC的获取，同时减少过度喂养动物的营养物质的获取。多种 将非妊娠母羊按体重分层，并随机分配至75 d提供的饮食治疗：200％的饮食建议（过量），100％的饮食建议（对照）或60％的饮食建议（不足）。ARC中表达POMC的神经元数量增加了（P ≤0.002）在营养不良的母羊。过量进料增加（P与控制和欠下料如使用免疫染色波形评估相比≤0.01）tanycyte细胞过程深度和密度。两次治疗之间沿3V壁紧密连接的免疫染色没有差异（P = 0.32）。毛细血管密度（没有观察到差异P = 0.21）或分类（P的ME内≥0.47）。这些结果表明，ARC中饱满中心的变化和单核细胞的形态发生是对养分有效性的适应。