2008-12-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/688105摘要：在神經發育中，規律的自發性活動是建立神經網路的重要因素。以發育中的視覺神經系統為例，在無任何感覺訊息傳入前，未成熟的視網膜神經節細胞會引發一連串的動作電位以影響視覺網路的建立。這種自發性的活動在時空上皆有特殊的規律，稱為「視網膜波」。先前的研究對於視網膜波如何產生，以及它在視網膜與大腦的連結上扮演的關鍵性角色都有相當的瞭解。然而，在單一細胞的層次上，規律的自發性活動如何調控RGCs中的基因表現仍是模糊不清。許多證據指出，神經放電活動會調控基因的表現，如調控與傳導物質釋放有關的 Synaptotagmin (Syt) 基因的表現，進而調控突觸的傳導功效以影響網路的建立。因此，我們假設視網膜波的放電規律應是調控 Syt基因表現的原因。此篇計畫的目標是在闡明視網膜波的放電規律如何導致Syt表現的變化。我們將結合藉由分子上的操作、單細胞反轉錄聚合酵素連鎖反應、初級離體視網膜培養、全細胞膜電位測量以及活細胞影像擷取，來回答以下問題：視網膜波放電規律的變化可否改變Syt基因的表現？哪一種Syt亞型的表現會受到視網膜波正向或負向的調控？ 而產生這種調控的訊息路徑是什麼？藉由解答這些問題，我們可以瞭解視網膜波如何建立適當的神經網路，這將對於理解神經系統發育的基礎機制有很大的意義。 <br> Abstract: The patterned spontaneous activity is a critical component to establish connections in the developing nervous system. In the developing visual system, before any sensory input is possible, immature retinal ganglion cells (RGCs) fire bursts of action potentials that propagate across the RGC layer to influence development of visual circuits. This spontaneous activity consists of distinct spatiotemporal patterns across the RGC layer termed as “retinal waves”. Previous studies have greatly contributed to the understanding of how these retinal waves are generated and what is the critical role they play in the proper wiring of retinal projections to central targets. However, it remains elusive at the single cellular level how the patterned spontaneous activity can affect gene expression in individual RGCs. Multiple evidences indicate that neural firing activity can up-regulate genes involved in neurotransmitter release, such as synaptotagmin (Syt). Therefore, we hypothesize that the firing patterns of retinal waves encode the information for Syt gene expression to regulate neurotransmitter release leading to modulation of synaptic efficacy and establishment of neural circuits. The goal of this proposal is to elucidate how the patterns of wave activity lead to alteration in the expression profile of Syt. By combining molecular perturbation, single-cell reverse transcriptase-PCR (RT-PCR), primary retinal explant culture, whole-cell patch clamp and live imaging, we will address the following questions. First, will the changes in the patterns of retinal waves alter expression of Syt genes? Second, which specific Syt isoform(s) is(are) up/down-regulated by retinal waves? Finally, what is(are) the underlying signaling pathway(s) by which Syt gene expression is regulated during the patterned spontaneous activity? By addressing these questions, we can understand how retinal waves establish proper connections of neural circuits. The results from this research proposal will be potentially significant for understanding the general mechanism in neural development.神經發育規律的自發性活動視網膜波Synaptotagmin基因表現Neural developmentPatterned spontaneous activityRetinal wavesSynaptotagminGene expression