中国明对虾脑发生和分化的细胞学观察

采用组织学和细胞学方法,初步研究了中国明对虾(Fenneropenaeus chinensis)脑的发生和分化过程。成神经细胞起源于原肠胚期,至膜内无节幼体期位于幼体前端;脑神经节起始于无节幼体Ⅰ期(N1),1对;无节幼体Ⅲ期(N3)脑神经节前端愈合;状幼体Ⅰ期(Z1)分化出嗅脑和前中后脑,此时前脑和中脑前端两侧愈合;仔虾期脑的大部分已经愈合,但后脑仍分离。随发育脑体积增加,髓质占脑体积的比例增加。脑神经细胞在无节幼体Ⅵ期(N6)初步分化为2类:Ⅰ类神经细胞核着色浅,异染色质较少;Ⅱ类神经细胞着色深,核内异染色质较多。神经分泌细胞(NSC)在Ⅱ期(Z2)出现,胞体巨大,电镜下可见分泌颗粒;随着发育该细胞数量逐渐增多。神经细胞体群在糠虾期(M)部分形成,至仔虾期(P)主要神经细胞体群初具规模。中国明对虾至仔虾早期脑的基本结构已经分化完成,但神经分泌细胞的种类和数量的增加有待进一步的发育完成。中国水产科学,2007,14(1):15-22]

Cytological observation of neurogenesis and differentiation of brain in shrimp Fenneropenaeus chinensis

Neurogenesis and development of brain has been studied by using the histological and cytological methods in Fenneropenaeus chinensis.The experiment would provide basic academic evidence for foundation of nervous,hormone control and phylogenetic evolution.The neuroblast originated at gastrula stage and was in front part of larva in membrane.Brain of F.chinensis,which was composed of a pair of ganglion cerebrales,originated at N_1 phase.The pair of ganglion cerebrales concrescenced at N_(3) in front part of brain.Brain was differentiated into protocerebrum,deutocerebrum,tritocerebrum and olfactory lobe at Z_(1) phase.Protocerebrum and the front of deutocerebrum concrescenced.Brain mostly concrescenced at P phase,while tritocerebrum was still separate.During development,both the volume of the brain and the ratio of neuropil in proportion to brain's volume increased.Two kinds of nerve cells were differentiated at N_(6) phase.The nucleus of type II was dyed deeply and had more heterochromatin,and that of type I was opposite.Neurosecretory cell(NSC) appeared at Z_(2) phase,which was huge.Neurosecretory granules were observed in it under electron microscope,and the number of NSC increased during the development.Nerve cell body clusters partially appeared at M phase and developed more perfectly at P phase.The primary structure of the brain in F.chinensis has been differentiated at early stage of P.However,the sort and number increase of NSC need to develop further.Journal of Fishery Sciences of China,2007,14(1):15-22]