期刊
EXPERIMENTAL NEUROLOGY
卷 183, 期 1, 页码 147-158出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/S0014-4886(03)00126-2
关键词
dentate gyrus; electron microscopy; hilus; aging; spatial learning performance; unmyelinated axon
资金
- NHLBI NIH HHS [HL18974] Funding Source: Medline
- NIA NIH HHS [AG09973] Funding Source: Medline
- NIDA NIH HHS [DA08259] Funding Source: Medline
- NIMH NIH HHS [MH42834] Funding Source: Medline
Neuropeptide Y-immunoreactive (NPY-I) interneurons in the dentate gyrus are vulnerable to various insults, including septohippocampal cholinergic deafferentation. The present study examined whether a loss of NPY-I neurons occurs during aging, when the functional integrity of the septohippocampal pathway is thought to be compromised. Sets of male Long Evans rats (consisting of young and aged rats, with and without spatial learning impairments assessed by the Mortis water maze) were examined. Light microscopic analysis revealed that hilar NPY-I neuronal number in matched dorsal sections was significantly decreased in aged compared to young rats. Ultrastructural analysis disclosed that the microenvironment (the types of processes apposed to the plasmalemmal surface) of NPY-I neurons also differed significantly between young and aged rats. In particular, a subgroup of NPY-I neurons, distinguished by a higher percentage of unmyelinated axon coverage of the plasmalemmal surface, was present in young, but not aged, rats. Neither the number nor the microenvironment of NPY-I neurons significantly differed between aged animals that were impaired versus unimpaired in spatial learning performance. To our knowledge these findings represent the first report of an age-associated decline in the number of a specific, neurochemically identified neuronal subpopulation within the hippocampal formation. Additionally, they closely parallel observations in 192 IgG-saporin-lesioned animals, suggesting that a distinct subgroup of NPY-I interneurons is particularly dependent on the viability of septohippocampal cholinergic innervation for its survival. Since neuronal loss was not correlated with performance, this alteration by itself does not appear to be sufficient to produce learning impairment. (C) 2003 Elsevier Science (USA). All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据