Petrov T, Krukoff T L, Jhamandas J H
Department of Anatomy and Cell Biology, Faculty of Medicine, University of Alberta, Edmonton, Canada.
Brain Res. 1993 Apr 23;609(1-2):81-92. doi: 10.1016/0006-8993(93)90858-k.
In this study, we have employed triple fluorescent-labelling to reveal the distribution of catecholaminergic neurons within three brainstem areas which supply branching collateral input to the central nucleus of the amygdala (CNA) and the hypothalamic paraventricular nucleus (PVN): the ventrolateral medulla (VLM), the nucleus of the solitary tract (NTS) and the locus coeruleus (LC). The catecholaminergic identity of the neurons was revealed by immunocytochemical detection of the biosynthetic enzyme, tyrosine hydroxylase. The projections were defined by injections of two retrograde tracers, rhodamine- and fluorescein-labelled latex microspheres, in the CNA and PVN, respectively. In the VLM and NTS, the greatest incidence of neurons which contained both retrograde tracers was found at the level of the area postrema. These neurons were mainly located within the confines of the A1/C1 (VLM) and A2 (NTS) catecholaminergic neuronal groups. Double-projecting neurons in the LC (A6) were distributed randomly within the nucleus. It was found that 15% in the VLM, 10% in the NTS and 5% in the LC of the retrogradely labelled cells projected via branching collaterals to the PVN and CNA. One half of these neurons in the VLM and NTS were catecholaminergic, in contrast to the LC where virtually all double-retrogradely labelled neurons revealed tyrosine hydroxylase immunoreactivity. In the other brainstem catecholaminergic cell groups (A5, A7, C3), no catecholaminergic neurons were found that supplied branching collaterals to the CNA and PVN. Our results indicate that brainstem neurons may be involved in the simultaneous transmission of autonomic-related signals to the CNA and the PVN. Catecholamines are involved in these pathways as chemical messengers. Brainstem catecholaminergic and non-catecholaminergic neurons, through collateral branching inputs may provide coordinated signalling of visceral input to rostral forebrain sites. This may lead to a synchronized response of the CNA and PVN for the maintenance of homeostasis.
在本研究中，我们采用三重荧光标记法来揭示三个脑干区域内儿茶酚胺能神经元的分布情况，这三个区域向杏仁核中央核（CNA）和下丘脑室旁核（PVN）提供分支侧支输入：腹外侧延髓（VLM）、孤束核（NTS）和蓝斑（LC）。通过免疫细胞化学检测生物合成酶酪氨酸羟化酶来揭示神经元的儿茶酚胺能特性。分别在CNA和PVN中注射两种逆行示踪剂罗丹明和荧光素标记的乳胶微球来确定投射。在VLM和NTS中，同时含有两种逆行示踪剂的神经元在最后区水平的发生率最高。这些神经元主要位于A1/C1（VLM）和A2（NTS）儿茶酚胺能神经元群范围内。LC（A6）中的双投射神经元在核内随机分布。发现VLM中15%、NTS中10%和LC中5%的逆行标记细胞通过分支侧支投射到PVN和CNA。VLM和NTS中这些神经元的一半是儿茶酚胺能的，而LC中几乎所有双逆行标记的神经元都显示出酪氨酸羟化酶免疫反应性。在其他脑干儿茶酚胺能细胞群（A5、A7、C3）中，未发现向CNA和PVN提供分支侧支的儿茶酚胺能神经元。我们的结果表明，脑干神经元可能参与将自主相关信号同时传递到CNA和PVN。儿茶酚胺作为化学信使参与这些通路。脑干儿茶酚胺能和非儿茶酚胺能神经元通过侧支分支输入可能为向脑前端脑部位的内脏输入提供协调信号。这可能导致CNA和PVN产生同步反应以维持体内平衡。
