Visually guided injection of identified reticulospinal neurons in zebrafish: A survey of spinal arborization patterns
Visually guided injection of identified reticulospinal neurons in zebrafish: A survey of spinal arborization patterns
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DOI：
10.1002/cne.10621
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发表时间：
2003-04-28
影响因子：
2.5
通讯作者：
O'Malley, DM
中科院分区：
文献类型：
--
作者：
Gahtan, E;O'Malley, DM
我们在这里报告的模式轴突分支的11个下降的细胞类型在幼虫脑干，这些细胞类型中的8个是单独确定的神经元。将得克萨斯红葡聚糖注射到尾脊髓中，在活体幼虫中逆行标记了大量的脑干神经元。随后，在每个幼虫中，使用荧光显微镜将Alexa 488葡聚糖体内注射单个鉴定的细胞，以引导注射移液管到达靶细胞。通过压力脉冲的细胞填充揭示了不同细胞类型的不同且通常广泛的脊髓轴突侧支。以前对毛特纳细胞的填充显示出短的、旋钮状的侧枝。与此相反，Mauthner细胞的两个节段同源细胞MiD 2cm和MiD 3cm显示轴突侧支，其广泛的分支沿着几乎整个脊髓以规则的间隔重复出现。此外，MiD 2cm的侧支循环以频繁的间隔穿过中线，产生在头-尾方向上运行的双侧乔木。其他髓网状脊髓细胞，以及细胞的内侧纵束（nMLF）的核，也表现出广泛的脊髓侧支，虽然每种细胞类型的模式不同。例如，nMLF细胞在延髓尾侧和脊髓远喙侧有广泛的侧支，但这些侧支在更尾部变得稀疏。两种细胞类型（CaD和RoL 1）显示乔木从背侧位于干轴突腹侧突出。观察到似乎可能具有生理学意义的其他细胞特异性特征。轴突侧支的喙尾分布是特别感兴趣的，因为它的影响，幼虫的运动曲目的下降控制。因为从一条鱼到另一条鱼可以识别出相同的个体细胞类型，这些解剖学观察可以直接与其他类型实验中获得的数据联系起来。例如，这里研究的11种细胞类型中有9种在逃避行为中表现出活性。
We report here the pattern of axonal branching for 11 descending cell types in the larval brainstem; eight of these cell types are individually identified neurons. Large numbers of brainstem neurons were retrogradely labeled in living larvae by injecting Texas-red dextran into caudal spinal cord. Subsequently, in each larva a single identified cell was injected in vivo with Alexa 488 dextran, using fluorescence microscopy to guide the injection pipette to the targeted cell. The filling of cells via pressure pulses revealed distinct and often extensive spinal axon collaterals for the different cell types. Previous fills of the Mauthner cell had revealed short, knob-like collaterals. In contrast, the two segmental homologs of the Mauthner cell, cells MiD2cm and MiD3cm, showed axon collaterals with extensive arbors recurring at regular intervals along nearly the full extent of spinal cord. Furthermore, the collaterals of MiD2cm crossed the midline at frequent intervals, yielding bilateral arbors that ran in the rostral-caudal direction. Other medullary reticulospinal cells, as well as cells of the nucleus of the medial longitudinal fasciculus (nMLF), also exhibited extensive spinal collaterals, although the patterns differed for each cell type. For example, nMLF cells had extensive collaterals in caudal medulla and far-rostral spinal cord, but these collaterals became sparse more caudally. Two cell types (CaD and RoL1) showed arbors projecting ventrally from a dorsally situated stem axon. Additional cell-specific features that seemed likely to be of physiological significance were observed. The rostral-caudal distribution of axon collaterals was of particular interest because of its implications for the descending control of the larva's locomotive repertoire. Because the same individual cell types can be identified from fish to fish, these anatomical observations can be directly linked to data obtained in other kinds of experiments. For example, 9 of the 11 cell types examined here have been shown to be active during escape behaviors.