Goldsmith P C, Song T
J Comp Neurol. 1987 Mar 1;257(1):130-9. doi: 10.1002/cne.902570110.
A well-defined, gonadotropin-releasing hormone (GnRH)-containing fiber pathway, the ventral hypothalamic tract (VHT), is described by immunostaining in fetal rhesus macaques (109-156 days gestation). The VHT arises above the lateral aspects of the optic chiasm near the supraoptic nucleus, and courses ventromedially close to the ventral hypothalamic surface to terminate in the infundibulum and zona externa of the median eminence. It is formed by the confluence of GnRH-immunopositive (GnRH+) axons from local neurons, from a few GnRH+ cells in the inferior thalamic peduncle, and probably from more anterior neurons in the septum and preoptic area. Bipolar GnRH+ neurons contributing directly to the VHT are grouped at its origin dorsolateral to the optic chiasm, dorsal and medial to the optic tracts, at the infundibular lip, and within the pathway between. At the infundibular lip, GnRH+ perikarya are generally lateral or ventral to the infundibular (arcuate) nucleus, and are rarely within the nucleus itself. Cell bodies here are sometimes tripolar, but GnRH+ intercellular contacts are seldom seen. A few VHT fibers extend to the ventral surface of the brain just beneath the pia mater. Abundant capillaries in the subarachnoid space suggest a possible route for delivery of GnRH to the adenohypophysis in early gestation, before maturation of the hypophysial portal system occurs. Posterior to the infundibulum, a few VHT fibers are joined by descending periventricular fibers forming a dense fiber band beneath the premammillary recess of the third ventricle. Totals of GnRH+ cell bodies in the prosencephalon of the fetal rhesus macaque are estimated to be 5,600 in females (n = 2) and 2,600 in males (n = 3). More than 60% of VHT neurons are located in the medial basal hypothalamus, and the majority of basal hypothalamic GnRH+ neurons (86%) are associated with the VHT. Furthermore, reports of the autonomy of the medial basal hypothalamic-hypophysial unit in control of gonadotropin secretion suggest that the VHT may be the most important GnRH system involved in primate reproduction. It is clear that fetal material may offer the best model to study the GnRH neuronal system in primates.
通过对妊娠109 - 156天的恒河猴胎儿进行免疫染色，描述了一条界限清晰、含有促性腺激素释放激素（GnRH）的纤维通路，即腹侧下丘脑束（VHT）。VHT起始于视交叉外侧上方靠近视上核的位置，向腹内侧走行，靠近下丘脑腹侧面，终止于正中隆起的漏斗部和外侧带。它由来自局部神经元、丘脑下脚少数GnRH免疫阳性（GnRH+）轴突以及可能来自隔区和视前区更靠前神经元的GnRH+轴突汇聚而成。直接汇入VHT的双极GnRH+神经元聚集在其起始部位，位于视交叉背外侧、视束背侧和内侧、漏斗唇以及其间的通路内。在漏斗唇处，GnRH+核周体通常位于漏斗（弓状）核的外侧或腹侧，很少位于核内本身。此处的细胞体有时为三极，但很少见到GnRH+细胞间的接触。一些VHT纤维延伸至软膜下方的脑腹表面。蛛网膜下腔丰富的毛细血管提示，在垂体门脉系统成熟之前，早期妊娠时GnRH可能通过这一途径输送至腺垂体。在漏斗后方，一些VHT纤维与下行的室周纤维汇合，在第三脑室乳头前隐窝下方形成一条致密的纤维带。估计雌性（n = 2）恒河猴胎儿前脑的GnRH+细胞体总数为5600个，雄性（n = 3）为2600个。超过60%的VHT神经元位于内侧基底下丘脑，并且大多数基底下丘脑GnRH+神经元（86%）与VHT相关。此外，关于内侧基底下丘脑 - 垂体单位在促性腺激素分泌控制方面自主性的报道表明，VHT可能是灵长类动物生殖过程中最重要的GnRH系统。显然，胎儿组织可能为研究灵长类动物GnRH神经元系统提供最佳模型。
