Role of vasoactive intestinal peptide in the light input to the circadian system.
Role of vasoactive intestinal peptide in the light input to the circadian system.
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DOI：
10.1111/ejn.12919
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发表时间：
2015-07
期刊：
影响因子：
--
通讯作者：
Colwell CS
中科院分区：
文献类型：
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作者：
Vosko A;van Diepen HC;Kuljis D;Chiu AM;Heyer D;Terra H;Carpenter E;Michel S;Meijer JH;Colwell CS
神经肽血管活性肠肽在视交叉上核(SCN)腹侧区的神经元亚群中高水平表达。虽然VIP对SCN网络的同步很重要，但VIP在昼夜节律系统的光调节中的作用却鲜有人关注。在目前的研究中，我们发现体内光诱发的电活动的增加不会因VIP的丧失而改变。在没有VIP的情况下，尽管治疗前后神经活动的绝对水平显著降低，但腹侧SCN在脑片制备中仍显示出NMDA诱发的反应。接下来，我们使用钙成像技术来确定血管活性肠肽的丢失是否改变了由于视网膜下丘脑束刺激而导致的钙内流。诱发钙内流的幅度在腹侧SCN没有减少，但在背侧SCN区域却有所下降。我们用原位杂交法检测了VIP突变小鼠SCN中Perod1光诱导的时间进程。我们发现，Perod1的初始诱导并不会因为失去这个信号肽而减少。然而，Perio1表达的持续增加(30min后)显著减少。通过测量SCN中CFO的光诱导，也发现了类似的结果。这些发现表明，VIP对于SCN回路中的长期变化是关键的，但在急性光反应中并不起作用。
The neuropeptide vasoactive intestinal peptide is expressed at high levels in a subset of neurons in ventral region of the suprachiasmatic nucleus (SCN). While VIP is known to be important for the synchronization of the SCN network, the role of VIP in photic regulation of the circadian system has received less attention. In the present study, we found that the light-evoked increase in electrical activity in vivo was unaltered by the loss of VIP. In the absence of VIP, the ventral SCN still exhibited NMDA-evoked responses in a brain slice preparation although the absolute levels of neural activity before and after treatment were significantly reduced. Next, we used calcium imaging techniques to determine if the loss of VIP altered the calcium influx due to retinohypothalamic tract stimulation. The magnitude of the evoked calcium influx was not reduced in the ventral SCN but did decline in the dorsal SCN regions. We examined the time course of the photic induction of Period1 in the SCN using in situ hybridization in VIP-mutant mice. We found that the initial induction of Period1 was not reduced by the loss of this signaling peptide. However, the sustained increase in Period1 expression (after 30 min) was significantly reduced. Similar results were found by measuring the light-induction of cFOS in the SCN. These findings suggest that VIP is critical for longer term changes within the SCN circuit but does not play a role in the acute light response.