Polston Eva K, Simerly Richard B
Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon 97006, USA.
J Comp Neurol. 2006 Mar 1;495(1):122-32. doi: 10.1002/cne.20874.
Neurons in the anteroventral periventricular nucleus of the hypothalamus (AVPV) mediate a variety of autonomic functions. In adults they primarily innervate neuroendocrine nuclei in the periventricular zone of the hypothalamus, including the paraventricular and arcuate nuclei (PVH, ARH). Ascending projections from the AVPV also provide inputs to the ventrolateral septum (LSv) and the principal division of the bed nuclei of the stria terminalis (BSTp). Consistent with a role in regulating preovulatory luteinizing hormone secretion, rostral projections from the AVPV contact gonadotropin-releasing hormone (GnRH) neurons surrounding the vascular organ of the lamina terminalis (OVLT). To study the development of these pathways, we placed implants of the lipophilic tracers DiI and CMDiI into the AVPV of female rats ranging in age from embryonic day 19 (E19) through adulthood. The earliest projections targeted a population of GnRH neurons, with apparent contacts from labeled fibers observed as early as E19. These connections appeared to be fully developed before birth, as similar numbers of appositions from AVPV projections onto the GnRH-immunoreactive cells were observed at all ages examined. Caudal projections were delayed relative to projections to the OVLT. Labeled AVPV fibers reached the PVH during the first postnatal week, and fibers targeting the BSTp and LSv were not observed until the second and third postnatal weeks, respectively. Labeled AVPV fibers were not seen in the ARH of animals at any age. Our results demonstrate that projections from the AVPV develop with both spatial and temporal specificity, innervating each target with a unique developmental profile.
下丘脑室前腹侧核（AVPV）中的神经元介导多种自主功能。在成年动物中，它们主要支配下丘脑室周区的神经内分泌核，包括室旁核和弓状核（PVH，ARH）。来自AVPV的上行投射也为腹外侧隔（LSv）和终纹床核主部（BSTp）提供输入。与调节排卵前促黄体生成素分泌的作用一致，AVPV的嘴侧投射与终板血管器（OVLT）周围的促性腺激素释放激素（GnRH）神经元接触。为了研究这些通路的发育，我们将亲脂性示踪剂DiI和CMDiI植入年龄从胚胎第19天（E19）到成年的雌性大鼠的AVPV中。最早的投射靶向一群GnRH神经元，早在E19时就观察到标记纤维有明显接触。这些连接在出生前似乎就已完全发育，因为在所有检查的年龄，从AVPV投射到GnRH免疫反应性细胞上的附着数量相似。相对于向OVLT的投射，尾侧投射有所延迟。标记的AVPV纤维在出生后的第一周到达PVH，而分别直到出生后的第二周和第三周才观察到靶向BSTp和LSv的纤维。在任何年龄的动物的ARH中都未见到标记的AVPV纤维。我们的结果表明，来自AVPV的投射在空间和时间上都具有特异性地发育，以独特的发育模式支配每个靶点。
