title: Aging-associated formaldehyde-induced norepinephrine deficiency contributes to age-related memory decline.
abstract: 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 (SAMP8) 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 (SAMR1) mice. Injection of resveratrol (a natural FA scavenger) or NE into SAMP8 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.
authors: Alzheimer's disease Center, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China.|Section of Environmental Biomedicine, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, 430079, China.
authors: Yufei
authors: Y
authors: Mei
authors: Neuroscience Research Institute & Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China.
authors: Chun
authors: C
authors: Jiang
authors: Neuroscience Research Institute & Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, 100191, China.
authors: You
authors: Y
authors: Wan
authors: Beijing Geriatric Hospital, Beijing, 100049, China.
authors: Jihui
authors: J
authors: Lv
authors: Alzheimer's disease Center, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China.
authors: Jianping
authors: J
authors: Jia
authors: Alzheimer's disease Center, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China.
authors: Xiaomin
authors: X
authors: Wang
authors: Section of Environmental Biomedicine, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, 430079, China.
authors: Xu
authors: X
authors: Yang
authors: Alzheimer's disease Center, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China.
authors: Zhiqian
authors: Z
authors: Tong
mesh_terms: D000375:Aging / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D001342:Autonomic Nervous System Diseases / Q000378:metabolism* / Q000473:pathology; D004299:Dopamine beta-Hydroxylase / Q000172:deficiency* / Q000378:metabolism; D005557:Formaldehyde / Q000008:administration & dosage* / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology; D007276:Injections, Intraventricular; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008569:Memory Disorders / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D009638:Norepinephrine / Q000008:administration & dosage / Q000172:deficiency* / Q000378:metabolism*; D016627:Oxidopamine / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D013238:Stereotaxic Techniques
chemical_list: D005557:Formaldehyde; D016627:Oxidopamine; D004299:Dopamine beta-Hydroxylase; D009638:Norepinephrine
keywords: formaldehyde; long-term potentiation; norepinephrine; senescence-accelerated prone 8; spatial memory; spontaneous discharge