Aicher S A, Reis D J, Ruggiero D A, Milner T A
Cornell University Medical College, Division of Neurobiology, New York, NY 10021.
Neuroscience. 1994 Jun;60(3):761-79. doi: 10.1016/0306-4522(94)90503-7.
Microinjection of L-glutamate into a subregion of the gigantocellular nucleus of the rat medulla oblongata significantly lowers arterial pressure. This vasodepressor area, the gigantocellular depressor area, is topographically distinct from other vasoactive areas of the medulla. We sought to determine the efferent projections of the gigantocellular depressor area and compare these to the efferent projections of sympathoexcitatory neurons within the rostral ventrolateral medulla. The anterograde tracer Phaseolus vulgaris-leucoagglutinin was deposited into sites in the gigantocellular depressor area or rostral ventrolateral medulla (pressor area) functionally defined as vasodepressor or vasopressor by microinjections of L-glutamate. Following Phaseolus vulgaris-leucoagglutinin injections into the gigantocellular depressor area, labeled punctuate fibers were seen bilaterally within distinct areas of a number of autonomic regions including the nuclei of the solitary tract, subcoeruleus area, parabrachial complex, the medial medullary reticular formation of the medulla and pons, and laminae 7 and 10 of the thoracic spinal cord. Following deposits into the rostral ventrolateral medulla (pressor area), labeled fibers were seen in many of these same autonomic nuclei; however, efferents from the gigantocellular depressor area to the nucleus of the solitary tract, the parabrachial complex and the reticular formation were medial to rostral ventrolateral medulla (pressor area) efferents to these same areas. These data indicate that neurons within the gigantocellular depressor area and the rostral ventrolateral medulla (pressor area) project to autonomic nuclei throughout the central nervous system and further suggest a heterogeneity of function with regard to autonomic control both within the reticular formation and its efferent targets. In addition, these data support the view that the gigantocellular depressor area may be a novel reticulospinal sympathoinhibitory area.
将L-谷氨酸微量注射到大鼠延髓巨细胞内核的一个亚区域可显著降低动脉血压。这个血管减压区域，即巨细胞减压区域，在地形上与延髓的其他血管活性区域不同。我们试图确定巨细胞减压区域的传出投射，并将其与延髓头端腹外侧部交感兴奋神经元的传出投射进行比较。将顺行示踪剂菜豆凝集素注入巨细胞减压区域或延髓头端腹外侧部（升压区域）的部位，这些部位通过微量注射L-谷氨酸在功能上被定义为血管减压或血管升压区域。在将菜豆凝集素注入巨细胞减压区域后，在包括孤束核、蓝斑下区域、臂旁复合体、延髓和脑桥的内侧髓质网状结构以及胸段脊髓第7和第10层在内的多个自主神经区域的不同区域内双侧可见标记的点状纤维。在将示踪剂注入延髓头端腹外侧部（升压区域）后，在许多相同的自主神经核中可见标记纤维；然而，从巨细胞减压区域到孤束核、臂旁复合体和网状结构的传出纤维位于延髓头端腹外侧部（升压区域）到这些相同区域的传出纤维的内侧。这些数据表明，巨细胞减压区域和延髓头端腹外侧部（升压区域）内的神经元投射到整个中枢神经系统的自主神经核，并且进一步表明在网状结构及其传出靶点内自主神经控制在功能上存在异质性。此外，这些数据支持这样一种观点，即巨细胞减压区域可能是一个新的网状脊髓交感抑制区域。
