Journal of Neuroscience, Vol 5, 2809-2814, Copyright © 1985 by Society for Neuroscience
Neurotrophic activity in the adult rat hippocampal formation: regional distribution and increase after septal lesion
F Collins and KA Crutcher
Conditioned medium prepared from slices of the rat hippocampal formation
contains an agent that shares the following properties with nerve growth
factor (NGF): it promotes neurite growth from embryonic sympathetic ganglia
in vitro; and it is inhibited by affinity-purified antibody against mouse
submaxillary gland 2.5 S NGF. The NGF-like growth-promoting activity is
regionally distributed within the hippocampal formation: the activity is
consistently higher in the dentate gyrus-CA3 region than in the CA1 region.
Furthermore, the level of activity is significantly increased within 1 week
after a medial septal lesion, and, in the dentate-CA3 region, the increased
level of activity is maintained for at least 4 weeks after the lesion.
Control lesions that fail to interrupt the septohippocampal innervation,
but cause equally extensive damage to nearby regions of the central nervous
system, do not cause increased levels of activity in the hippocampal
formation. These results provide substantial evidence linking the NGF- like
agent in hippocampal conditioned medium to the sprouting of sympathetic
axons into the dentate gyrus-CA3 region of the hippocampal formation after
a medial septal lesion in vivo.