Enkephalin innervation of the paraventricular nucleus of the hypothalamus: Distribution of fibers and origins of input
Enkephalin innervation of the paraventricular nucleus of the hypothalamus: Distribution of fibers and origins of input
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DOI：
10.1016/0891-0618(95)00105-0
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发表时间：
1996-04-01
影响因子：
2.8
通讯作者：
Drolet, G
中科院分区：
文献类型：
--
作者：
Beaulieu, J;Champagne, D;Drolet, G
阿片肽脑啡肽作为一种主要的神经调质出现在应激条件下的生理反应的调节和整合。下丘脑室旁核是神经内分泌和自主神经功能的协调中心。然而，室旁核内脑啡肽纤维和终末的详细分布以及脑啡肽能神经支配的来源尚不清楚。本研究应用脑啡肽原八肽met-arg（6）-gly（7）-leu（8）脑啡肽免疫细胞化学方法，观察室旁核内脑啡肽免疫反应纤维和胞体的分布。没有秋水仙碱预处理，脑啡肽能纤维突出，主要是在室旁核的小细胞分部的腹内侧部分，出现在冠状面作为一个密集的收集短节的脑啡肽免疫反应纤维。在室旁核的室周部分，脑啡肽免疫反应纤维产生了一个中等丛的短脑啡肽免疫反应纤维背腹向。秋水仙碱处理，脑啡肽免疫反应阳性细胞体的密集集群位于背内侧和背侧部分的小细胞亚部。这些脑啡肽免疫反应神经元是小（< 10 μ m）至中等大小（10-15 μ m），具有圆形和细长形。小麦胚标记金颗粒WGA-apoHRP-Au从室旁核的逆行转运结合脑啡肽的免疫细胞化学研究表明，下丘脑外脑啡肽传入室旁核的主要来源是延髓外侧网状核和巨细胞旁网状核的脑啡肽神经元（类似于该核内20%的逆行标记神经元被双标记）和孤束核（类似于该核内10%的逆行标记神经元被双标记）。在内侧视前区、正中视前核、下丘脑背内侧核、外侧隔和下丘脑弓状核也观察到逆行标记的脑啡肽神经元。这些来自延髓和前脑的脑啡肽能通路可以代表生理过程中阿片类药物对室旁神经元作用的解剖学基础，例如心血管调节、进食或应激反应。
The opioid peptide enkephalin emerges as a major neuromodulator in the regulation and integration of the physiologic response in stressful conditions. The paraventricular nucleus of the hypothalamus is a coordinating center of neuroendocrine and autonomic functions. However, the detailed distribution of the enkephalin fibers and terminals in the paraventricular nucleus and the sources of enkephalinergic innervation are not well defined. In the present study, we used immunocytochemistry for the proenkephalin-derived octapeptide met-arg(6)-gly(7)-leu(8) enkephalin to determine the distribution of enkephalin-immunoreactive fibers and somata within paraventricular nucleus. Without colchicine pretreatment, enkephalinergic fibers were prominent mainly in the ventromedial part of the parvicellular subdivision of the paraventricular nucleus, appearing in coronal sections as a dense collection of short segments of enkephalin-immunoreactive fibers. In the periventricular portion of the paraventricular nucleus, enkephalin-immunoreactive fibers produced a moderate plexus of short enkephalin-immunoreactive fibers dorsoventrally oriented. With colchicine treatment, a dense cluster of enkephalin-immunoreactive cell bodies was located in the dorsomedial and the dorsal parts of the parvicellular subdivisions. These enkephalin-immunoreactive neurons were small (< 10 mu m) to medium sized (10-15 mu m), with round and elongated shapes. Retrogade transport of wheat germ-conjugated gold particles, WGA-apoHRP-Au, from the paraventricular nucleus, combined with immunocytochemistry for enkephalin revealed that the major sources of extrahypothalamic enkephalin afferents to the paraventricular nucleus are provided by enkephalin neurons in the lateral reticular nucleus and the paragigantocellularis reticular nucleus of the medulla (similar to 20% of retrogradely labeled neurons within this nucleus were double labeled) and in the nucleus solitary tract (similar to 10% of retrogradely labeled neurons within this nucleus were double labeled). Retrogradely labeled enkephalin neurons were also observed in the medial preoptic area, median preoptic nucleus, dorsomedial hypothalamic nucleus, lateral septum and hypothalamic arcuate nucleus. These enkephalinergic pathways from the medulla and the forebrain could represent an anatomical substrate underlying the opioid effects on paraventricular neurons during physiological processes, such as cardiovascular regulation, feeding or stress responses.