There is only one known portal system in the mammalian brain - that of the pituitary gland, first identified in 1933 by Popa and Fielding. Here we describe a second portal pathway in the mouse linking the capillary vessels of the brain’s clock suprachiasmatic nucleus (SCN) to those of the organum vasculosum of the lamina terminalis (OVLT), a circumventricular organ. The localized blood vessels of portal pathways enable small amounts of important secretions to reach their specialized targets in high concentrations without dilution in the general circulatory system. These brain clock portal vessels point to an entirely new route and targets for secreted SCN signals, and potentially restructures our understanding of brain communication pathways.

哺乳动物大脑中只有一个已知的门静脉系统——垂体，于 1933 年首次由 Popa 和 Fielding 发现。在这里，我们描述了小鼠的第二个门户通路，将大脑时钟视交叉上核（SCN）的毛细血管与终板血管器（OVLT）​​（一种心室周围器官）的毛细血管连接起来。门脉通路的局部血管使少量的重要分泌物能够以高浓度到达其特定目标，而无需在全身循环系统中稀释。这些脑钟门脉血管为分泌的 SCN 信号指明了一条全新的路线和目标，并有可能重建我们对大脑通讯途径的理解。