Open AccessAging‐associated formaldehyde‐induced norepinephrine deficiency contributes to age‐related memory decline
Author(s) -
Mei Yufei,
Jiang Chun,
Wan You,
Lv Jihui,
Jia Jianping,
Wang Xiaomin,
Yang Xu,
Tong Zhiqian
Publication year - 2015
Publication title -
aging cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.103
H-Index - 140
eISSN - 1474-9726
pISSN - 1474-9718
DOI - 10.1111/acel.12345
Subject(s) - hippocampal formation , senescence , long term potentiation , medicine , endocrinology , hippocampus , norepinephrine , cognitive decline , endogeny , biology , resveratrol , disease , pharmacology , dementia , dopamine , receptor
Summary A norepinephrine ( NE ) deficiency has been observed in aged rats and in patients with Alzheimer's disease and is thought to cause cognitive disorder. Which endogenous factor induces NE depletion, however, is largely unknown. In this study, we investigated the effects of aging‐associated formaldehyde ( FA ) on the inactivation of NE in vitro and in vivo , and on memory behaviors in rodents. The results showed that age‐related DNA demethylation led to hippocampal FA accumulation, and when this occurred, the hippocampal NE content was reduced in healthy male rats of different ages. Furthermore, biochemical analysis revealed that FA rapidly inactivated NE in vitro and that an intrahippocampal injection of FA markedly reduced hippocampal NE levels in healthy adult rats. Unexpectedly, an injection of FA (at a pathological level) or 6‐hydroxydopamine (6‐ OHDA , a NE depletor) can mimic age‐related NE deficiency, long‐term potentiation ( LTP ) impairments, and spatial memory deficits in healthy adult rats. Conversely, an injection of NE reversed age‐related deficits in both LTP and memory in aged rats. In agreement with the above results, the senescence‐accelerated prone 8 ( SAMP 8) mice also exhibited a severe deficit in LTP and memory associated with a more severe NE deficiency and FA accumulation, when compared with the age‐matched, senescence‐resistant 1 ( SAMR 1) mice. Injection of resveratrol (a natural FA scavenger) or NE into SAMP 8 mice reversed FA accumulation and NE deficiency and restored the magnitude of LTP and memory. Collectively, these findings suggest that accumulated FA is a critical endogenous factor for aging‐associated NE depletion and cognitive decline.