Teclemariam-Mesbah R, Ter Horst G J, Postema F, Wortel J, Buijs R M
Netherlands Institute for Brain Research, Amsterdam.
J Comp Neurol. 1999 Apr 5;406(2):171-82.
A polysynaptic pathway is proposed to transmit light information from the retina through the suprachiasmatic nucleus of the hypothalamus (SCN) to the pineal. In the present study, the powerful transneuronal tracer, pseudorabies virus (PRV), was used to provide a detailed description of this pathway. PRV injected into the pineal subsequently labeled the superior cervical ganglion, the intermediolateral column of the upper thoracic cord, the autonomic division of the paraventricular nucleus of the hypothalamus (PVN), and the SCN. Neurons in the autonomic division of the PVN were the only PRV-labeled neurons in the hypothalamus shown to receive input from the SCN as demonstrated by the presence of vasoactive intestinal polypeptide axonal contacts. This observation concurred with the presence of ventrally placed neurons in the SCN that could only be observed a day after the appearance of PVN-labeled neurons. Nevertheless the majority of the neurons were found in the dorsomedial position of the SCN, associated with the vasopressin-containing population of SCN neurons. Confocal laser scanning microscopy showed double-labeled neurons containing PRV and vasopressin or PRV and vasoactive intestinal polypeptide. Specificity of tracing was also established by prior removal of the superior cervical ganglion, resulting in a complete absence of the tracer but in the pineal. Thus, the present study provides the anatomical basis for circadian control of melatonin secretion.
有人提出一条多突触通路可将视网膜的光信息通过下丘脑视交叉上核（SCN）传递至松果体。在本研究中，使用了强大的跨神经元示踪剂伪狂犬病病毒（PRV）来详细描述这条通路。将PRV注入松果体后，随后标记了颈上神经节、上胸段脊髓的中间外侧柱、下丘脑室旁核（PVN）的自主神经部以及SCN。PVN自主神经部的神经元是下丘脑中唯一被PRV标记且被证明接受来自SCN输入的神经元，血管活性肠肽轴突接触的存在证明了这一点。这一观察结果与SCN中腹侧神经元的存在相一致，这些神经元只能在PVN标记神经元出现一天后才能观察到。然而，大多数神经元位于SCN的背内侧位置，与含有加压素的SCN神经元群体相关。共聚焦激光扫描显微镜显示了含有PRV和加压素或PRV和血管活性肠肽的双标记神经元。通过事先切除颈上神经节也确定了示踪的特异性，结果导致松果体中完全没有示踪剂。因此，本研究为褪黑素分泌的昼夜节律控制提供了解剖学基础。
