Takamura K
Department of Biotechnology, Faculty of Engineering, Fukuyama University, Fukuyama 729-02, Japan.
Dev Genes Evol. 1998 Mar;208(1):1-8. doi: 10.1007/s004270050147.
With the use of the monoclonal antibody UA301, which specifically recognizes the nervous system in ascidian larvae, the neuronal connections of the peripheral and central nervous systems in the ascidian Ciona intestinalis were observed. Three types of peripheral nervous system neurons were found: two located in the larval trunk and the other in the larval tail. These neurons were epidermal and their axons extended to the central nervous system and connected with the visceral ganglion directly or indirectly. The most rostral system (rostral trunk epidermal neurons, RTEN) was distributed bilateral-symmetrically. In addition, presumptive papillar neurons in palps were found which might be related to the RTEN. Another neuron group (apical trunk epidermal neurons, ATEN) was located in the apical part of the trunk. The caudal peripheral nervous system (caudal epidermal neurons, CEN) was located at the dorsal and ventral midline of the caudal epidermis. In the larval central nervous system, two major axon bundles were observed: one was of a photoreceptor complex and the other was connected with RTEN. These axon bundles joined in the posterior sensory vesicle, ran posteriorly through the visceral ganglion and branched into two caudal nerves which ran along the lateral walls of the caudal nerve tube. In addition, some immunopositive cells existed in the most proximal part of the caudal nerve tube and may be motoneurons.
利用单克隆抗体UA301（该抗体能特异性识别海鞘幼虫的神经系统），观察了海鞘Ciona intestinalis外周和中枢神经系统的神经元连接。发现了三种类型的外周神经系统神经元：两种位于幼虫躯干，另一种位于幼虫尾部。这些神经元是表皮神经元，其轴突延伸至中枢神经系统，并直接或间接地与内脏神经节相连。最前端的系统（前端躯干表皮神经元，RTEN）呈双侧对称分布。此外，还发现了触须中可能与RTEN相关的假定乳头神经元。另一组神经元（顶端躯干表皮神经元，ATEN）位于躯干顶端。尾部外周神经系统（尾部表皮神经元，CEN）位于尾部表皮的背中线和腹中线。在幼虫中枢神经系统中，观察到两个主要的轴突束：一个是光感受器复合体的轴突束，另一个与RTEN相连。这些轴突束在后部感觉泡中汇合，向后穿过内脏神经节，并分支成两条沿着尾神经管侧壁延伸的尾神经。此外，在尾神经管最靠近近端的部分存在一些免疫阳性细胞，可能是运动神经元。
