Larsen P J, Hay-Schmidt A, Mikkelsen J D
Institute of Medical Anatomy, Department B, University of Copenhagen, Denmark.
J Comp Neurol. 1994 Apr 8;342(2):299-319. doi: 10.1002/cne.903420211.
The lateral preoptic and lateral hypothalamic regions contain the majority of the cell groups embedded in the fibre trajectories of the medial forebrain bundle on its course through the hypothalamus. Recent studies have extended considerably the parcellation of the lateral hypothalamic region, and therefore, the need to emphasize new insights into the anatomical organisation of projections from the neurons of the lateral hypothalamic region. In the present study we describe the anatomical organisation of efferent projections from the lateral preoptic and lateral hypothalamic regions to the hypothalamic paraventricular nucleus (PVN) on the basis of retrograde- and anterograde-tracing techniques. Iontophoretic injections of the retrograde tracer, cholera toxin subunit B, into the PVN revealed that most hypothalamic nuclei project to the PVN. Within the lateral hypothalamic region, retrogradely labelled cells were concentrated in the intermediate hypothalamic area, the lateral hypothalamic area, and the perifornical nucleus, whereas fewer retrogradely labelled cells were found in the lateral preoptic area. To determine the distribution of terminating fibres in subnuclei of the heterogeneous PVN, iontophoretic injections of the anterograde tracer Phaseolus vulgaris-leucoagglutinin were delivered into distinct areas of the lateral hypothalamic region. Neurons of the intermediate hypothalamic area projected mainly to the PVN subnuclei, which contained parvicellular neuroendocrine cells. In contrast, neurons of the rostral and tuberal parts of the lateral hypothalamic area and the perifornical nucleus projected to the PVN subnuclei, which contained parvicellular neurons that send descending projections to preganglionic cell groups in the medulla and spinal cord. The perifornical nucleus was the only area within the lateral hypothalamic region that consistently innervated magnocellular perikarya of the PVN. Finally, all areas of the lateral hypothalamic region contributed substantially to fibres terminating in the perinuclear shell of the PVN. These results demonstrate that anatomically distinct areas of the lateral hypothalamic region have distinct projections to subnuclei of the PVN and further substantiate the view that the lateral hypothalamic region as well as the PVN constitute anatomically and functionally heterogeneous structures.
外侧视前区和外侧下丘脑区包含了大部分嵌入内侧前脑束纤维轨迹中的细胞群，内侧前脑束在下丘脑行程中穿过这些区域。最近的研究极大地扩展了外侧下丘脑区的细胞构筑划分，因此，有必要强调对外侧下丘脑区神经元投射的解剖组织的新见解。在本研究中，我们基于逆行和顺行追踪技术，描述了外侧视前区和外侧下丘脑区向下丘脑室旁核（PVN）的传出投射的解剖组织。向PVN离子导入逆行示踪剂霍乱毒素B亚单位，结果显示大多数下丘脑核团都投射到PVN。在外侧下丘脑区内，逆行标记的细胞集中在下丘脑中间区、外侧下丘脑区和穹窿周核，而在外侧视前区发现的逆行标记细胞较少。为了确定在异质性PVN各亚核中终末纤维的分布，将顺行示踪剂菜豆凝集素离子导入外侧下丘脑区的不同区域。下丘脑中间区的神经元主要投射到包含小细胞神经内分泌细胞的PVN亚核。相反，外侧下丘脑区头端和结节部以及穹窿周核的神经元投射到包含向延髓和脊髓的节前细胞群发出下行投射的小细胞神经元的PVN亚核。穹窿周核是外侧下丘脑区内唯一始终支配PVN大细胞胞体的区域。最后，外侧下丘脑区的所有区域都对终止于PVN核周壳的纤维有显著贡献。这些结果表明，外侧下丘脑区在解剖学上不同的区域对PVN的亚核有不同的投射，并进一步证实了外侧下丘脑区以及PVN在解剖学和功能上构成异质性结构的观点。
