Journal of Neuroscience, Vol 7, 1919-1927, Copyright © 1987 by Society for Neuroscience
Cell death during gangliogenesis in the leech: bipolar cells appear and then degenerate in all ganglia
RR Stewart, WQ Gao, A Peinado, B Zipser and ER Macagno
The bipolar cells can be recognized very early during gangliogenesis in the
leech central nervous system by their expression of antigens that are
recognized by the monoclonal antibody Laz1-1. They are the first cells to
express these antigens, which are later shared with a distinct set of other
cells in the leech nervous system. Their processes extend several segments
rostrally and caudally along the forming interganglionic connective nerves;
they are first found in anterior segments and gradually appear in more
posterior ones over the course of 2-3 d. At about the time bipolar cells
appear in the neuromeres of the tail ganglion, those in the most anterior
segmental ganglia begin to degenerate. Degeneration proceeds caudally over
the next 3 d, until all bipolar cells have disappeared. Bipolar cells are,
thus, members of that class of cells that exists for only a short period in
neurogenesis and then presumably disappears once its functions are no
longer required. These cells' morphology and appearance at the earliest
stages in the formation of the interganglionic connective nerves are
suggestive of a role in the establishment of these longitudinal pathways in
the leech CNS.