M. Sakaguchi et al., STRUCTURE, DEVELOPMENT, AND MAINTENANCE OF THE NERVE NET OF THE BODY COLUMN IN HYDRA, Journal of comparative neurology, 373(1), 1996, pp. 41-54
The anatomy and developmental dynamics of the nerve net in the body co
lumn of Hydra viridissima were examined immunocytochemically with a mo
noclonal antibody (CC04) that recognizes an antigen in nerve cells and
with an antiserum against vasopressin. CC04(+) neuron cell bodies, th
eir neurites, and vasopressin-like-immunoreactive (VLI(+)) neurites co
uld be clearly visualized on whole-mount preparations. All neurites of
the CC04(+) neurons in the body column were VLI(+). However, only hal
f of the VLI(+) neurites in the body column were CC04(+). Immunocytoch
emical analysis of macerated preparations showed that half of the neur
ons in the gastric region of the body column were CC04(+). These resul
ts suggest that most of the neurons in the gastric region are VLI(+).
The density of the VLI(+) neurites was uniform along the entire length
of the body column. The CC04(+) neuron density in the gastric region
remained constant at all stages of asexual development and during foot
regeneration. After pulse-labeling with 5-bromo-2'-deoxyuridine (BrdU
), CC04(+) neurons with labeled nuclei appeared in the body column. We
conclude that neuron density in the gastric region is maintained at a
constant value by insertion of new neurons in parallel with continuou
s epithelial cell division. (C) 1996 Wiley-Liss, Inc.