Journal of Neuroscience, Vol 7, 244-251, Copyright © 1987 by Society for Neuroscience
Increased beta-nerve growth factor messenger RNA and protein levels in neonatal rat hippocampus following specific cholinergic lesions
SR Whittemore, L Larkfors, T Ebendal, VR Holets, A Ericsson and H Persson
High levels of NGF have recently been detected in cerebral cortex and
hippocampus, and it was suggested that NGF supports cholinergic, basal
forebrain neurons. The present study directly examined whether NGF levels
are altered in the neonatal hippocampus following cholinergic denervation
by transection of the fimbria. Ten days after transection, hippocampal
cholinergic innervation, as assessed by AChE histochemistry and CAT
immunohistochemistry, was decreased, and both hippocampal NGF mRNA and
protein were elevated about 50%. This indicates possible lesion-induced
transcriptional control of neonatal hippocampal NGF levels. This increase
was specific to lesions of cholinergic systems, as entorhinal cortex
ablation, which removes other afferent fibers to the hippocampus, did not
cause a similar increase. At 30 d after fimbria transection, hippocampal
NGF mRNA and protein did not differ from control levels, but the decrease
in AChE and CAT staining persisted. Peripheral sympathectomy carried out in
the adult rat resulted in 2- to 5-fold increases in NGF protein levels in
heart atrium and ventricle, as well as submandibular gland, with no
concomitant increase in NGF mRNA. Therefore, the control of NGF levels in
the adult PNS is probably posttranscriptional. Our results strongly suggest
that NGF is involved in the regulation of central cholinergic neurons and
is transiently elevated in the neonatal hippocampus following cholinergic
lesion.