Hatton G I
Department of Neuroscience, University of California, Riverside 92521, USA.
Annu Rev Neurosci. 1997;20:375-97. doi: 10.1146/annurev.neuro.20.1.375.
Physiological activation of the magnocellular hypothalamo-neurohypophysial system induces a coordinated astrocytic withdrawal from between the magnocellular somata and the parallel-projecting dendrites of the supraoptic nucleus. Neural lobe astrocytes release engulfed axons and retract from their usual positions along the basal lamina. Occurring on a minutes-to-hours time scale, these changes are accompanied by increased direct apposition of both somatic and dendritic membrane, the formation of dendritic bundles, the appearance of novel multiple synapses in both the somatic and dendritic zones, and increased neural occupation of the perivascular basal lamina. Reversal, albeit with varying time courses, is achieved by removing the activating stimuli. Additionally, activation results in interneuronal coupling increases that are capable of being modulated synaptically via second messenger-dependent mechanisms. These changes appear to play important roles in control and coordination of oxytocin and vasopressin release during such conditions as lactation and dehydration.
大细胞下丘脑 - 神经垂体系统的生理激活会诱导星形胶质细胞从大细胞胞体与视上核平行投射的树突之间协调撤离。神经叶星形胶质细胞释放被吞噬的轴突，并从其沿基膜的正常位置缩回。这些变化发生在数分钟到数小时的时间尺度上，同时伴随着胞体和树突膜直接贴附增加、树突束形成、胞体和树突区域出现新的多个突触以及血管周围基膜的神经占据增加。通过去除激活刺激可实现逆转，尽管时间进程不同。此外，激活会导致中间神经元耦合增加，这种增加能够通过依赖第二信使的机制进行突触调节。这些变化似乎在泌乳和脱水等情况下催产素和抗利尿激素释放的控制与协调中发挥重要作用。
