Larsen P J, Mikkelsen J D
Department B, University of Copenhagen, Denmark.
J Comp Neurol. 1992 Dec 8;326(2):180-92. doi: 10.1002/cne.903260203.
The distribution of vasoactive intestinal peptide (VIP) was analysed in perikarya of the mink hypothalamus with immunohistochemistry and, surprisingly, a large population of magnocellular VIP-immunoreactive neurons was present in the paraventricular and supraoptic nuclei as well as in accessory hypothalamic nuclei. From perikarya in the paraventricular as well as supraoptic nuclei, a large number of VIP immunoreactive nerve fibers was observed to enter the hypothalamo-neurohypophysial tract. Within the median eminence, a high density of VIP-immunoreactive nerve fibers was present in the external and internal zones. Fibers in the external zone of the median eminence were endowed with varicosities and perivascular terminals, while fibers in the internal zone were smooth and without terminal specializations. From the internal zone of the median eminence, fibers coursed via the infundibular stalk to terminate in perivascularly situated terminals in the neurohypophysis. In addition, a substantial number of small VIP-immunoreactive perikarya was observed within the suprachiasmatic nucleus. These perikarya were immunoreactive to neither vasopressin nor neurophysin. To elucidate the co-existence of VIP-immunoreactivity with vasopressin, oxytocin or neurophysin, a sequential double immunoperoxidase procedure to localize antigens with diaminobenzidine and benzidine dihydrochloride as chromagens was performed. From these experiments it was evident that VIP in nearly all magnocellular hypothalamo-neurohypophysial neurons co-existed with neurophysin. Based on a semi-quantitative estimate, half the VIP-immunoreactive magnocellular perikarya co-stored vasopressin, while another half co-stored oxytoxin. The present study describes the presence of a large population of VIP-containing neurons in the hypothalamo-neurohypophysial system of the mink. These findings raise evidence that within the mink, VIP may be involved in neurohypophysial physiology.
采用免疫组织化学方法分析了水貂下丘脑核周质中血管活性肠肽（VIP）的分布，令人惊讶的是，室旁核、视上核以及下丘脑附属核中存在大量大细胞VIP免疫反应性神经元。在室旁核和视上核的核周质中，观察到大量VIP免疫反应性神经纤维进入下丘脑 - 神经垂体束。在正中隆起内，外部和内部区域存在高密度的VIP免疫反应性神经纤维。正中隆起外部区域的纤维具有膨体和血管周终末，而内部区域的纤维则是光滑的，没有终末特化。从正中隆起的内部区域，纤维经漏斗柄走行，终止于神经垂体中位于血管周围的终末。此外，在视交叉上核内观察到大量小的VIP免疫反应性核周质。这些核周质对加压素和神经垂体素均无免疫反应。为了阐明VIP免疫反应性与加压素、催产素或神经垂体素的共存情况，采用了以二氨基联苯胺和盐酸联苯胺作为显色剂的连续双重免疫过氧化物酶法来定位抗原。从这些实验中可以明显看出，几乎所有下丘脑 - 神经垂体大细胞神经元中的VIP都与神经垂体素共存。基于半定量估计，一半的VIP免疫反应性大细胞核周质共同储存加压素，而另一半共同储存催产素。本研究描述了水貂下丘脑 - 神经垂体系统中存在大量含VIP的神经元。这些发现提供了证据，表明在水貂体内，VIP可能参与神经垂体的生理功能。
