Postnatal changes of vesicular glutamate transporter (VGluT)1 and VGluT2 immunoreactivities and their colocalization in the mouse forebrain
Postnatal changes of vesicular glutamate transporter (VGluT)1 and VGluT2 immunoreactivities and their colocalization in the mouse forebrain
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DOI：
10.1002/cne.20705
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发表时间：
2005-11-21
影响因子：
2.5
通讯作者：
Kaneko, T
中科院分区：
文献类型：
--
作者：
Nakamura, K;Hioki, H;Kaneko, T
囊泡谷氨酸转运蛋白 1 (VGluT1) 和 VGluT2 将神经递质谷氨酸积累到突触前末端的突触小泡中，因此它们的抗体被认为是谷氨酸能轴突末端的良好标记。在本研究中，我们通过对小鼠前脑（包括端脑和间脑）中 VGluT1 和 VGluT2 进行单免疫和双免疫标记，研究了谷氨酸能神经元系统的出生后发育和成熟。从出生后第0天（P0）到成年期，VGluT2免疫反应性广泛分布于前脑，特别是间脑，表明负载VGluT2的谷氨酸能轴突相对较早成熟。相比之下，VGluT1 免疫反应性仅在 P0 时在边缘区域强烈，并在出生后三周期间在其他端脑和间脑区域急剧增加。有趣的是，VGluT1 免疫反应性经常与 VGluT2 免疫反应性共定位于 P5 至 P10 初级体感区 IV 层以及 P0 至 P14 腹侧后内侧丘脑核中的单轴突末端样轮廓。这与嗅球肾小球、尾壳核斑片区域和腹侧后外侧丘脑核中几乎没有发现共定位的发现形成鲜明对比，其中 VGluT1 和 VGluT2 的中度至强烈免疫反应性在出生后发育过程中在神经毡中相互混合。目前的结果表明，在小鼠端脑和间脑区域，加载 VGluT2 的谷氨酸轴突比加载 VGluT1 的轴突成熟得更早，并表明 VGluT1 在一些成年期主要使用 VGluT2 的谷氨酸能系统中发挥短暂的发育作用。
Vesicular glutamate transporter 1 (VGluT1) and VGluT2 accumulate neurotransmitter glutamate into synaptic vesicles at presynaptic terminals, and their antibodies are thus considered to be a good marker for glutamatergic axon terminals. In the present study, we investigated the postnatal development and maturation of glutamatergic neuronal systems by single- and double-immunolabelings for VGluT1 and VGluT2 in mouse forebrain including the telencephalon and diencephalon. VGluT2 immunoreactivity was widely distributed in the forebrain, particularly in the diencephalon, from postnatal day 0 (P0) to adulthood, suggesting relatively early maturation of VGluT2-loaded glutamatergic axons. In contrast, VGluT1 immunoreactivity was intense only in the limbic regions at P0, and drastically increased in the other telencephalic and diencephalic regions during three postnatal weeks. Interestingly, VGluT1 immunoreactivity was frequently colocalized with VGluT2 immunoreactivity at single axon terminal-like profiles in layer IV of the primary somatosensory area from P5 to P10 and in the ventral posteromedial thalamic nucleus from P0 to P14. This was in sharp contrast to the finding that almost no colocalization was found in glomeruli of the olfactory bulb, patchy regions of the caudate-putamen, and the ventral posterolateral thalamic nucleus, where moderate to intense immunoreactivities for VGluT1 and VGluT2 were intermingled with each other in neuropil during postnatal development. The present results indicate that VGluT2-loaded glutamatergic axons maturate earlier than VGluT1-laden axons in the mouse telencephalic and diencephalic regions, and suggest that VGluT1 plays a transient developmental role in some glutamatergic systems that mainly use VGluT2 in the adulthood.