Morphologycal analysses of the neural components of the input and output pathways involved in the Drosophila circadian system, with special reference to the cholinergic neurons.

对果蝇昼夜节律系统输入和输出通路的神经成分进行形态学分析，特别是胆碱能神经元。

基本信息

批准号：
09640816
负责人：
YASUYAMA Kouji
金额：
$ 2.05万
依托单位：
Kawasaki Medical School
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

In Drasophila, various lines of evidence suggest that the circadian pacemakers for daily locomotor rhythms reside in the cells called "lateral neurons" (LNs) lying in the anterior rind of the medulla. However, little is known about the neural pathways linking these pacemaker cells to behavioral rhythms. To identify the neural components of the input and output pathways of the Drosophila circadian clock system, we have surveyed the brain using immunocytochemical techniques, especially with reference to cholinergic neurons. A monoclonal antibody against Drosophila choline acetyltransferase (ChAT) stained a group of extraretinal photoreceptors at the posterior margin of the compound eye, which is called the "eyelet". The axons emerging from the eyelet terminated in the region of the anterior medulla, where the possible dendritic field of LNs resides. LNs were immunoreactive to an antibody against Drosophila nAChR, implying cholinergic input to LNs. This circumstantial evidence suggests th … More at the eyelet is involved in an input pathway contributing to circadian entrainment. Transformed flies carrying the transgene composed of ChAT cDNA with 1.2 kb of the cis-regulatory sequence showed obviously reduced ChAT expression in specific subsets of cholinergic neurons, such as the neurons terminating in the distal region of the medulla, where the varicosity of the output fibers of LNs resides. A morphometric study revealed that LN varicosity in the medulla was -significantly larger in the transformants than in the wild-type flies. The transformants entrained to light : dark cycles, and exhibited a double-peaked locomotor activity pattern with morning and evening peaks, as did control flies (white). When the illumination level was low (I.e., 0.24 lux), the transformants showed unusual monophagic locomotor activity exclusively occurring during the entire light phase, in contrast to double-peaked activity in the controls. These observations suggest that defects in ChAT expression resulted in the extraordinary locomotor rhythms in the transformants. Less

在Drasophila中，各种证据表明，每日运动节奏的昼夜节律起搏器居住在称为“外侧神经元”（LNS）的细胞中，位于髓质的前果皮中。然而，对于将这些起搏器细胞与行为节奏联系起来的神经元知之甚少。为了确定果蝇昼夜节律时钟系统输入和输出途径的神经元成分，我们使用免疫细胞化学技术调查了大脑，尤其是在胆碱能神经元中。针对果蝇胆碱乙酰基转移酶（CHAT）的单克隆抗体在化合物的后缘染色了一组一组心外感光体，这称为“孔眼”。从孔眼中出现的轴突终止于前髓质区域，其中可能是LNS的树突状场。 LN对针对果蝇NACHR的抗体进行免疫反应，从而实现了对LN的胆碱能输入。这个间接证据表明，孔眼上的更多内容参与了导致昼夜节律入口的输入途径。携带聊天cDNA转化的转化的苍蝇，带有1.2 kb的顺式调节序列，显示出明显降低了胆碱能神经元的特定子集的聊天表达，例如终止在髓质远端区域的神经元，其中LNS的输出纤维均存在。一项形态计量学研究表明，髓质中的LN静脉曲张在转化体中比野生型苍蝇大。变成光的转化体：黑暗周期，并与早晨甚至峰值暴露了双峰的运动活动模式，对照苍蝇（白色）也是如此。当照明水平较低（即0.24 lux）时，与对照组中的双峰活动相比，转化子仅在整个光阶段出现异常单声道运动活性。这些观察结果表明，聊天表达中的缺陷导致转化体中的非凡运动节奏。较少的