DISTRIBUTION OF VGluT1 AND VGluT2 IN THE SPINAL CORD IN DIFFERENT MAMMALIAN SPECIES: RAT, CAT AND MONKEY / 解剖学报

ABSTRACT

Objective To investigate the distribution of the vesicular glutamate transporters (VGluTs), VGIuT1 and VGIuT2, in the spinal cord in multiple species, including rat, cat and monkey. Methods An immunohistochemical technique was used in the present study. Results VGluTs were observed in the gray matter of the spinal cord of rat, cat and monkey. VGluTl-immunoreactivity (VGluT1-IR) was most intense in the inner part of lamina Ⅱ(Ⅱi) and the medial parts of laminae Ⅲ-Ⅵ of the spinal dorsal horn; weak in lamina Ⅰ and outer part of lamina Ⅱ(Ⅱo); moderate in other parts in the rat and cat. The laminar distribution of VGluT1-IR in the spinal cord in the monkey is different from those in the rat and cat. The VGluT1-immunopositive product was intense in laminae Ⅰ, Ⅱi, Ⅲ and the medial parts of laminae Ⅳ-Ⅵ of the spinal dorsal horn; weak to absent in lamina Ⅱo and the lateral parts of laminae Ⅳ-Ⅵ of the dorsal horn. In the spinal anterior horn of monkey, the VGluT1-immunoreactive profiles were observed sparsely just in lamina Ⅸ, not in other laminae. At the same time, some scattered immunoreactive profiles were present in the white matter, particularly at the medial parts of the dorsal column in monkey, but not in rat and cat. On the other hand, VGluT2 immunoreactivity (VGluT2-IR) was moderately present throughout the gray matter, it was most dense in laminae Ⅰ-Ⅱ and Ⅹ, and weak in the medial parts of the deep spinal dorsal horn (laminae Ⅲ-Ⅵ) in the three species. The VGluT2-immunopositive product was very sparse in the lateral parts of the deep spinal dorsal horn of the monkey. In the lateral spinal nuclei of the rat, moderate VGluT2-immunopositive product could be seen, but not in the cat and monkey. In three species, both VGluT1- and VGluT2-IR showed a punctuate distribution. Conclusion The present results indicated that VGluT1 and VGluT2 were expressed in the spinal cord in all species examined but differentially distributed in a species-specific manner, and they might play an important role in the activities of the excitatory neurons in the spinal cord of rat, cat and monkey.