Magoul R, Dubourg P, Benjelloun W, Tramu G
Laboratoire de Neurocytochimie Fonctionnelle, URA CNRS 339, Talence, France.
Neuroscience. 1993 Aug;55(4):1055-66. doi: 10.1016/0306-4522(93)90319-b.
The origin of both direct and indirect enkephalinergic innervation potentially able to influence neurons of the rat arcuate nucleus has been investigated by combining enkephalin immunocytochemistry and retrograde axonal transport of a wheatgerm agglutinin-Apo horseradish peroxidase-gold complex. Twenty four hours after tissue injections of small volumes (20 nl) of the tracer into the arcuate nucleus, rats were treated with colchicine and killed. In order to localize the enkephalinergic cells which directly innervate the arcuate nucleus, Vibratome sections were first silver-stained for detection of the wheatgerm agglutinin-Apohorseradish peroxidase-gold complex and then processed for enkephalin immunohistochemistry. To study the indirect enkephalinergic input to the arcuate nucleus, an electron microscope detection of immunoreactive synapses was carried out in areas rich in retrogradely labeled perikarya. Perikarya both immunoreactive and retrogradely labeled were observed ipsilaterally to the injection site in telencephalic structures such as the bed nucleus of the stria terminalis, medial preoptic and adjacent periventricular areas. Hypothalamic ipsilateral doubly labeled cells were localized principally in the dorsomedial nucleus and rostral arcuate nucleus. The major direct inputs arising from brainstem structures concerns the dorsal and ventral parabrachial nuclei. Moreover, at the ultrastructural level, numerous enkephalinergic terminals were demonstrated to synapse with retrogradely labeled perikarya and dendrites localized in the medial preoptic area, the hypothalamic paraventricular nucleus and the parabrachial nuclei providing evidence for an important enkephalinergic input on neurons projecting to the arcuate nucleus. Taken together, our light and electron microscope studies strongly suggest that the arcuate nucleus is the target of an enkephalinergic control originating from several regions and acting either directly or indirectly on neurons projecting to the arcuate nucleus.
通过将脑啡肽免疫细胞化学与小麦胚凝集素 - 载脂蛋白辣根过氧化物酶 - 金复合物的逆行轴突运输相结合，研究了可能影响大鼠弓状核神经元的直接和间接脑啡肽能神经支配的起源。在将小体积（20 nl）示踪剂注射到弓状核后24小时，用秋水仙碱处理大鼠并将其处死。为了定位直接支配弓状核的脑啡肽能细胞，首先对振动切片机切片进行银染以检测小麦胚凝集素 - 载脂蛋白辣根过氧化物酶 - 金复合物，然后进行脑啡肽免疫组织化学处理。为了研究对弓状核的间接脑啡肽能输入，在富含逆行标记核周体的区域进行了免疫反应性突触的电子显微镜检测。在端脑结构如终纹床核、内侧视前区和相邻的室周区域中，在注射部位同侧观察到了免疫反应性和逆行标记的核周体。下丘脑同侧的双标记细胞主要位于背内侧核和弓状核前部。来自脑干结构的主要直接输入涉及背侧和腹侧臂旁核。此外,在超微结构水平上，大量脑啡肽能终末被证明与位于内侧视前区、下丘脑室旁核和臂旁核的逆行标记核周体和树突形成突触，这为投射到弓状核的神经元上存在重要的脑啡肽能输入提供了证据。综上所述，我们的光学显微镜和电子显微镜研究强烈表明，弓状核是源自多个区域的脑啡肽能控制的靶标，该控制直接或间接作用于投射到弓状核的神经元。
