期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1992
卷号：89
期号：7
页码：2639-2643
DOI：10.1073/pnas.89.7.2639
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：In this study light and EM quantitative analysis were used to examine whether exogenous nerve growth factor (NGF) could affect terminal fields and synaptic connections in the adult rat brain in vivo. Adult rats received, immediately after unilateral decortication, 2.5S NGF (12 micrograms/day) or vehicle intracerebroventricularly for 7 days. Thirty days after the lesion cholinergic fiber length was quantified, using image analysis, in the remaining cortical area adjacent to the lesion site in each animal. Rats that had received vehicle showed a significantly reduced cortical choline acetyl-transferase-immunoreactive fiber network in the remaining cortex when compared with control animals. By contrast, the network in lesioned rats that had received 2.5S NGF was not different from control animals. Furthermore, the number of cortical choline acetyltransferase-immunoreactive varicosities, which decreased in vehicle-treated lesioned rats, significantly increased above control in lesioned rats that had received 2.5S NGF. At the ultrastructural level, 30 days after the lesion, animals that had received vehicle showed shrunken cholinergic boutons in cortical layer V and fewer synapses compared with control animals. Exogenous NGF, administered to lesioned rats, increased to supernormal levels both size of cholinergic boutons and number of synaptic contacts. These parameters were unaltered in unlesioned rats treated with NGF. This study demonstrates that exogenous NGF can cause significant compensatory changes in terminal fields and synaptic connections in the adult fully differentiated central nervous system.
