Structure of the Planarian Central Nervous System (CNS) Revealed by Neuronal Cell Markers

• DOI: 10.2108/zsj.15.433
• Publication Date: 2004-11-25T06:03:34Z
• Authors: Kiyokazu Agata; Yukihiro Soejima; Kentaro Kato; Chiyoko Kobayashi; Yoshihiko Umesono; Kenji Watanabe
• Keywords: Planarian

Planarians are considered to be among the most primitive animals which developed central nervous system (CNS). To understand origin and evolution of CNS, we have isolated a neural marker gene from planarian, Dugesia japonica, analyzed structure planarian CNS by in situ hybridization. The is located on ventral side body, composed mass cephalic ganglions head region pair nerve cords (VNC). Cephalic cluster independently VNC, more dorsal than form an inverted U-shaped brain-like with nine branches each outer side. Two eyes 3(rd) branch visual axons optic chiasma dorsal-inside brain. 6(th)-9(th) closely auricles surface may function as sensory organ taste. We found that gross along anterior-posterior (A-P) axis strikingly similar distribution pattern "primary" neurons vertebrate embryos differentiate at plate stage provide fundamental system, although These data suggest basic plan for development A-P might been acquired early before conversion location