GLUTAMATE IMMUNOREACTIVITY IN TERMINALS OF THE RETINOHYPOTHALAMIC TRACT OF THE BROWN NORWEGIAN RAT
GLUTAMATE IMMUNOREACTIVITY IN TERMINALS OF THE RETINOHYPOTHALAMIC TRACT OF THE BROWN NORWEGIAN RAT
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DOI：
10.1016/0006-8993(93)91665-f
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发表时间：
1993-05-28
期刊：
影响因子：
2.9
通讯作者：
MEIJER, JH
中科院分区：
文献类型：
--
作者：
DEVRIES, MJ;CARDOZO, BN;MEIJER, JH
哺乳动物视交叉上核(SCN)的昼夜节律起搏器通过视网膜投射--视网膜下丘脑束(RHT)进入环境的明暗循环。几项研究表明，一种兴奋性氨基酸，可能是谷氨酸，参与了光夹带。然而，谷氨酸是否是RHT本身的一种递质还没有确定。我们现在通过玻璃体内注射霍乱毒素偶联的辣根过氧化物酶，在棕色挪威大鼠的SCN中鉴定了RHT的终末。为了检测谷氨酸免疫反应性(IR)，用多克隆抗体进行包埋后免疫细胞化学，并用胶体金颗粒在电子显微镜下观察。视网膜终末的谷氨酸-IR比突触后树突高82%，比非视网膜终末的谷氨酸-IR高76%。这些观察结果为谷氨酸是RHT的一种递质提供了超微结构证据。
The mammalian circadian pacemaker of the suprachiasmatic nucleus (SCN) is entrained to the environmental light-dark cycle via a retinal projection, the retinohypothalamic tract (RHT). Several studies suggest that an excitatory amino acid, possibly glutamate, is involved in photic entrainment. However, it has not yet been established whether glutamate is a transmitter of the RHT itself. We have now identified terminals of the RHT in the SCN of brown Norwegian rats by intravitreous injections of horse radish peroxidase conjugated to cholera toxin. To detect glutamate immunoreactivity (IR), post-embedding immunocytochemistry was performed with polyclonal antibodies which were visualized for electron microscopy with colloidal gold particles. Retinal terminals had a significantly 82% higher glutamate-IR than their post-synaptic dendrites and a significantly 76% higher glutamate-IR than non-retinal terminals. These observations provide ultrastructural evidence that glutamate is a transmitter of the RHT.