Reproductive Endocrinology Center, Box 0556, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, School of Medicine, San Francisco, California 94143-0556, USA.
J Neuroendocrinol. 1990 Apr 1;2(2):169-79. doi: 10.1111/j.1365-2826.1990.tb00847.x.
Abstract In order to localize neuroendocrine dopamine neurons in the monkey hypothalamus, one female and three male juvenile cynomolgus macaques were each given two or three microinjections (0.2 to 0.3 mul per site) of the retrograde tracer wheat germ agglutinin-apoHorseradish peroxidase-10 nm colloidal gold into the superficial, median eminence region of the infundibular stalk. Five to 15 days following surgery, the brains were fixed by perfusion, and vibratomed at 40 pm in the frontal plane. Every 12th section was immunostained with rabbit anti-tyrosine hydroxylase using the peroxidase anti-peroxidase technique with diaminobenzidine as the chromogen. Neuroendocrine, immunoreactive neurons were easily recognized as brown, immunopositive cell bodies containing more than three distinct dark blue granules, confirmed by electron microscopy to be tracer-filled lysosomes. Neuronal counts from each complete series of sections were compiled by anatomical region, and the percentages of tyrosine hydroxylase-immunoreactive and neuroendocrine, immunoreactive neurons determined. Although regional and interanimal variations were observed, we estimated that 5,400 of the total 19,000 tyrosine hydroxylaseimmunoreactive neurons in the juvenile macaque hypothalamus were neuroendocrine. When averaged by anatomical region, the suprachiasmatic nuclear groups contained 7% of all immunoreactive neurons (50% were neuroendocrine) and 15% of all neuroendocrine, immunoreactive neurons in these animals. The combined periventricular zones contained 20% of all immunoreactive neurons (more than 50% of ventral and 38% of dorsal were neuroendocrine) and 58% of all neuroendocrine, immunoreactive neurons. The paraventricular nucleus included 50% of all immunoreactive neurons, more than any other nucleus, (3% were neuroendocrine) and 11% of the total neuroendocrine, immunoreactive neurons. The ventral paraventricular nucleus contained only 2% of all immunoreactive neurons (13% were neuroendocrine) and 3% of the total neuroendocrine group. The zona incerta contained 15% of all immunoreactive neurons (0% were retrogradely labeled) but 0% of the neuroendocrine cells. The arcuate nucleus subdivisions contained about 5% of all immunoreactive neurons (more than 60% were neuroendocrine) and 8% of the neuroendocrine population. The ventral hypothalamic tract contained about 1% of all immunoreactive neurons (medially, 63%, and further laterally, 25% were neuroendocrine) and 5% of all neuroendocrine, immunoreactive neurons in these animals. The presence of the retrograde tracer from the median eminence in tyrosine hydroxylase-immunoreactive neurons, combined with knowledge of the location of dopaminergic cell groups, permitted assessment of the A11-A14 dopaminergic neurons which project to the primate infundibulum. Neuroendocrine dopamine neurons occurred predominantly in the All periventricular zones (65% of the total), being greatest around the ventral aspect of the entire third ventricle. They were less numerous in more dorsal regions of All extending up to the level of the paraventricular nucleus. The A12 arcuate (tuberoinfundibular) projection (15% of the total) was not nearly as prominent as All in primates, in contrast to rodents. None of the A13 incertohypothalamic dopamine neurons (0%) projected to the median eminence. The A14 anterior-ventral periventricular region, including the suprachiasmatic nuclear groups, provided the substantial remainder (20%) of all neuroendocrine dopamine neurons. In summary, our results suggest the involvement of a regionally specific dopaminergic system in the hypothalamic control of anterior pituitary hormone secretion in primates. The data also indicate that 75% of all tyrosine hydroxylase-immunopositive neurons do not project to the median eminence, and probably serve other functions. Although the retrograde tracer may not have labeled all neuroendocrine dopamine neurons, it may have identified some dopamine neurons which only interact with other median eminence nerve terminals, or other types of tyrosine hydroxylase-containing, neuropeptidergic neurons which project to the infundibulum. However, considering the known locations of dopaminergic neurons and the large numbers of labeled cells, the results here are a reliable indication of the diverse origins of median eminence-directed dopamine neurons in the juvenile primate.
为了在猴下丘脑定位神经内分泌多巴胺神经元，将一雌三雄共四只幼年食蟹猴用微量注射器（每次 0.2-0.3μl 每点）向漏斗柄的中脑隆起浅部和中部各注射三次逆行示踪剂——麦胚凝集素-辣根过氧化物酶-10nm 胶体金。术后 5-15 天，用灌注固定大脑，40μm 厚的冠状面振动切片。用辣根过氧化物酶抗过氧化物酶技术和二氨基联苯胺作为显色剂，用兔抗酪氨酸羟化酶免疫染色，每隔 12 张切片染色一次。神经内分泌，免疫反应性神经元很容易被识别为棕色，免疫阳性细胞体含有三个以上不同的深蓝色颗粒，电镜证实为示踪剂填充的溶酶体。通过解剖区域对每个完整系列切片的神经元计数，并确定酪氨酸羟化酶免疫反应性和神经内分泌，免疫反应性神经元的百分比。尽管观察到区域和动物间的变化，但我们估计，在幼年食蟹猴下丘脑的 19000 个酪氨酸羟化酶免疫反应性神经元中，有 5400 个是神经内分泌的。按解剖区域平均，视交叉上核群包含所有免疫反应性神经元的 7%（50%为神经内分泌）和这些动物所有神经内分泌，免疫反应性神经元的 15%。联合室周区包含所有免疫反应性神经元的 20%（腹侧多于 50%，背侧多于 38%为神经内分泌）和所有神经内分泌，免疫反应性神经元的 58%。室旁核包含所有免疫反应性神经元的 50%，比任何其他核都多（3%为神经内分泌），占总神经内分泌，免疫反应性神经元的 11%。腹侧室旁核只包含所有免疫反应性神经元的 2%（13%为神经内分泌）和总神经内分泌细胞群的 3%。未定带包含所有免疫反应性神经元的 15%（0%被逆行标记），但没有神经内分泌细胞。弓状核亚区包含所有免疫反应性神经元的约 5%（超过 60%为神经内分泌）和神经内分泌群体的 8%。腹下丘脑束包含所有免疫反应性神经元的约 1%（内侧，63%，进一步外侧，25%为神经内分泌）和这些动物所有神经内分泌，免疫反应性神经元的 5%。在位于中脑隆起的酪氨酸羟化酶免疫反应性神经元中存在逆行示踪剂，再加上已知的多巴胺能细胞群的位置，允许评估投射到灵长类动物漏斗的 A11-A14 多巴胺能神经元。神经内分泌多巴胺神经元主要存在于所有室周区（占总数的 65%），在整个第三脑室腹侧周围最为常见。在 A1 所有的更背侧区域，它们的数量较少，延伸到室旁核水平。A12 弓状（结节漏斗）投射（占总数的 15%）在灵长类动物中不像在啮齿动物中那样显著。没有 A13 未定带下丘脑多巴胺神经元（0%）投射到中脑隆起。包括视交叉上核群在内的 A14 前腹室周区提供了所有神经内分泌多巴胺神经元的剩余部分（20%）。总之，我们的结果表明，在灵长类动物的垂体前叶激素分泌的下丘脑控制中，涉及到一个具有区域特异性的多巴胺能系统。这些数据还表明，75%的所有酪氨酸羟化酶免疫阳性神经元不投射到中脑隆起，可能发挥其他功能。尽管逆行示踪剂可能没有标记所有的神经内分泌多巴胺神经元，但它可能已经识别了一些多巴胺神经元，这些神经元仅与中脑隆起的其他神经末梢相互作用，或者与投射到漏斗的其他类型的含有酪氨酸羟化酶的神经肽神经元相互作用。然而，考虑到已知的多巴胺能神经元的位置和大量标记的细胞，这里的结果可靠地表明了幼年灵长类动物中中脑隆起定向多巴胺神经元的不同起源。
