Herbert H, Saper C B
Department of Animal Physiology, University of Tübingen, Germany.
J Comp Neurol. 1992 Jan 1;315(1):34-52. doi: 10.1002/cne.903150104.
The periaqueductal or midbrain central gray matter (CG) in the rat contains a dense network of adrenergic and noradrenergic fibers. We examined the origin of this innervation by using retrograde and anterograde axonal tracers combined with immunohistochemistry for the catecholamine biosynthetic enzymes tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), and phenylethanolamine N-methyltransferase (PNMT). Following injections of the fluorescent tracers Fast Blue or Fluorogold into the CG, double-labeled neurons in the medulla were identified mainly in the noradrenergic A1 group in the caudal ventrolateral medulla (VLM) and A2 group in the medial part of the nucleus of the solitary tract (NTS); and in the adrenergic C1 group in the rostral ventrolateral medulla and C3 group in the rostral dorsomedial medulla. Injections of Phaseolus vulgaris-leucoagglutinin (PHA-L) into these cell groups resulted in a distinct pattern of axonal labeling in various subdivisions of the CG. Anterogradely labeled fibers originating in the medial NTS were predominantly found in the lateral portion of the dorsal raphe nucleus and in the adjacent part of the lateroventral CG (CGlv). Following PHA-L injections into the C3 region the anterogradely labeled fibers were diffusely distributed in the CGlv and the dorsal raphe nucleus at caudal levels, but rostrally tended to be located laterally in the CGlv. In contrast, ascending fibers from the caudal and rostral VLM terminated in the rostral dorsal part of the CGlv and in the dorsal nucleus of the CG, whereas ventral parts of the CG, including the dorsal raphe nucleus, contained few afferent fibers. Double-label studies with antisera against DBH and PNMT confirmed that noradrenergic neurons in the A1 and A2 groups and adrenergic neurons in the C1 and C3 groups contributed to these innervation patterns in the CGlv. Noradrenergic and adrenergic projections from the medulla to the CG may play an important role in a variety of autonomic, sensory and behavioral processes.
大鼠中脑导水管周围或中脑中央灰质（CG）含有密集的肾上腺素能和去甲肾上腺素能纤维网络。我们通过逆行和顺行轴突示踪剂结合儿茶酚胺生物合成酶酪氨酸羟化酶（TH）、多巴胺β-羟化酶（DBH）和苯乙醇胺N-甲基转移酶（PNMT）的免疫组织化学方法，研究了这种神经支配的起源。在将荧光示踪剂快蓝或氟金注射到CG后，延髓中的双标记神经元主要在尾侧腹外侧延髓（VLM）的去甲肾上腺素能A1组和孤束核（NTS）内侧部分的A2组中被识别；以及在延髓头端腹外侧的肾上腺素能C1组和延髓头端背内侧的C3组中被识别。将菜豆白细胞凝集素（PHA-L）注射到这些细胞群中，导致CG各个亚区出现明显的轴突标记模式。起源于内侧NTS的顺行标记纤维主要见于中缝背核的外侧部分和腹外侧CG（CGlv）的相邻部分。在将PHA-L注射到C3区域后，顺行标记纤维在尾侧水平的CGlv和中缝背核中呈弥漫性分布，但在头端倾向于位于CGlv的外侧。相比之下，来自尾侧和头端VLM的上行纤维终止于CGlv的头端背侧部分和CG的背核，而CG的腹侧部分，包括中缝背核，传入纤维很少。用抗DBH和PNMT的抗血清进行的双标记研究证实，A1和A2组中的去甲肾上腺素能神经元以及C1和C3组中的肾上腺素能神经元促成了CGlv中的这些神经支配模式。从延髓到CG的去甲肾上腺素能和肾上腺素能投射可能在各种自主、感觉和行为过程中发挥重要作用。
