Neuronal competition determines the spatial pattern of neuropeptide expression by identified neurons of the leech.
Neuronal competition determines the spatial pattern of neuropeptide expression by identified neurons of the leech.
复制标题
神经元竞争通过已识别的水蛭神经元决定神经肽表达的空间模式。
DOI：
10.1016/0012-1606(90)90289-u
复制
发表时间：
1990
影响因子：
2.7
通讯作者：
Shankland,M
中科院分区：
文献类型：
--
作者：
Martindale,MQ;Shankland,M
用软体动物神经肽小心脏活性肽B（SCP）和FMRFamide的抗体对成年和胚胎水蛭腹神经索进行染色，导致细胞染色的片段特异性和双侧不对称模式。一个免疫反应性神经元，RAS中间神经元，是目前只有四个吻节，而另一个，CAS中间神经元，仅限于四个最尾腹神经节和尾巴。除了它们的节段特异性分布之外，在每个节段神经节中仅发现一个RAS或CAS细胞，并且它们以约95%的保真度在相邻神经节（L-R-L-R或R-L-R-L）之间交替。本文利用细胞删除技术研究RAS和CAS神经元的不对称和交替模式的确定。我们发现，发育等价RAS和CAS同源物存在于适当的神经节的两侧，并且在每个神经节内，最初配对的同源物之一在轴突发生开始后2-3天失去承担免疫反应性RAS或CAS命运的能力。这些实验表明，有一个竞争性的双边同源物之间的相互作用，确保只有一个成熟的RAS/CAS神经元形成每个神经节，并对侧RAS/CAS神经元不需要在相同或相邻的神经节的RAS或CAS发育途径的确定。神经节之间的神经索横断在CAS域可以改变CAS神经元的决定的空间模式，确认双边同系物保留表达神经肽的能力，直到胚胎晚期阶段，并表明RAS/CAS细胞的交替模式需要相邻神经节之间的通信通过纵向连接。
Staining adult and embryonic leech ventral nerve cords with antibodies raised against the molluscan neuropeptides small cardioactive peptide B (SCP) and FMRFamide results in segment-specific and bilaterally asymmetric patterns of cell staining. One immunoreactive neuron, the RAS interneuron, is present in only four rostral segmental ganglia, while another, the CAS interneuron, is restricted to the four most caudal abdominal ganglia and tail. In addition to their segment-specific distributions, only one RAS or CAS cell is found in each segmental ganglion, and they alternate sides between adjacent ganglia (either L-R-L-R or R-L-R-L) with a fidelity of about 95%. This paper utilizes cell deletion techniques to investigate the determination of the asymmetric and alternating pattern of RAS and CAS neurons. We show that developmentally equivalent RAS and CAS homologs are present on both sides of the appropriate ganglia, and that within each ganglion one of the initially paired homologs loses the ability to assume the immunoreactive RAS or CAS fate 2–3 days after axonogenesis has begun. These experiments suggest that there is a competitive interaction between bilateral homologs which ensures that only one mature RAS/CAS neuron is formed per ganglion, and that contralateral RAS/CAS neurons are not required in the same or adjacent ganglia for the determination of the RAS or CAS developmental pathways. Nerve cord transections between ganglia in the CAS domain can alter the spatial pattern of CAS neuron determination, confirming that both bilateral homologs retain the ability to express neuropeptide until late embryonic stages, and suggesting that the alternating pattern of RAS/CAS cells requires communication between adjacent ganglia through the longitudinal connectives.