Shinohara K, Funabashi T, Kimura F
Department of Physiology, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.
Brain Res Mol Brain Res. 1999 Jan 8;63(2):262-7. doi: 10.1016/s0169-328x(98)00289-7.
Many vasoactive intestinal polypeptide (VIP) neurons are distributed in the suprachiasmatic nucleus (SCN) and most of them arborize throughout the nuclei. We determined temporal patterns of VIP receptor (VPAC2 receptor) mRNA in the rat SCN in constant darkness and light-dark cycles, by means of in situ hybridization histochemistry. Amounts of VIP precursor mRNA in the SCN were also quantified in adjacent sections to compare its temporal profile with that of VPAC2 receptor mRNA. In constant darkness no circadian rhythms in VIP precursor mRNA or VPAC2 receptor mRNA in the SCN were detected. In light-dark cycles VIP precursor mRNA and VPAC2 receptor mRNA in the SCN showed robust but different daily rhythms. VPAC2 receptor mRNA decreased over the course of the light period and then gradually recovered during the dark period. VIP precursor mRNA was also reduced in response to light but the reduction was transient. This difference in the nature of light responsiveness between VIP mRNA and VPAC2 receptor mRNA suggests that pre- and postsynaptic events of the VIP transduction system represent different stages of light information processing in the SCN.
许多血管活性肠肽（VIP）神经元分布在视交叉上核（SCN）中，其中大多数神经元的树突遍布整个核团。我们通过原位杂交组织化学方法，确定了在持续黑暗和明暗循环条件下，大鼠SCN中VIP受体（VPAC2受体）mRNA的时间模式。在相邻切片中还对SCN中VIP前体mRNA的量进行了定量，以将其时间分布与VPAC2受体mRNA的进行比较。在持续黑暗条件下，未检测到SCN中VIP前体mRNA或VPAC2受体mRNA的昼夜节律。在明暗循环条件下，SCN中的VIP前体mRNA和VPAC2受体mRNA表现出强烈但不同的每日节律。VPAC2受体mRNA在光照期间减少，然后在黑暗期间逐渐恢复。VIP前体mRNA也会因光照而减少，但这种减少是短暂的。VIP mRNA和VPAC2受体mRNA在光反应性质上的这种差异表明，VIP转导系统的突触前和突触后事件代表了SCN中光信息处理的不同阶段。
