title: Olfactory dysfunction and neurotransmitter disturbance in olfactory bulb of transgenic mice expressing human A53T mutant α-synuclein.
abstract: Parkinson disease is a multi-system neurodegenerative disease characterized by both motor and non-motor symptoms. Hyposmia is one of the early non-motor symptoms occurring in more than 90% of Parkinson disease cases, which can precede motor symptoms even several years. Up to now, the relationship between hyposmia and Parkinson disease remains elusive. Lack of proper animal models of hyposmia restricts the investigation. In this study we assessed olfactory function in Prp-A53T-α-synuclein transgenic (αSynA53T) mice which had been reported to show age-dependent motor impairments and intracytoplasmic inclusions. We also examined cholinergic and dopaminergic systems in olfactory bulb of αSynA53T mice by immunofluorescent staining, enzyme linked immunosorbent assay and western blot. We found that compared to wild type littermates, αSynA53T mice at 6 months or older displayed a deficit of odor discrimination and odor detection. No significant changes were found in olfactory memory and odor habituation. Furthermore compared to wildtype littermates, in olfactory bulb of αSynA53T mice at 10 months old we detected a marked decrease of cholinergic neurons in mitral cell layer and a decrease of acetylcholinesterase activity, while dopaminergic neurons were found increased in glomerular layer, accompanied with an increase of tyrosine hydroxylase protein. Our studies indicate that αSynA53T mice have olfactory dysfunction before motor deficits occur, and the cholinergic and dopaminergic disturbance might be responsible for the Parkinson disease-related olfactory dysfunction.
authors: Institute of Neurology, RuiJin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors: Sufang
authors: S
authors: Zhang
authors: Institute of Neurology, RuiJin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors: Qian
authors: Q
authors: Xiao
authors: Institute of Neurology, RuiJin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; State Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors: Weidong
authors: W
authors: Le
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004192:Discrimination, Psychological; D006801:Humans; D007124:Immunoenzyme Techniques; D008124:Locomotion; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009154:Mutation / Q000235:genetics*; D009474:Neurons / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism*; D000857:Olfaction Disorders / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D009830:Olfactory Bulb / Q000378:metabolism / Q000473:pathology*; D012678:Sensation Disorders; D012903:Smell; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D051844:alpha-Synuclein / Q000235:genetics / Q000378:metabolism*
chemical_list: D018377:Neurotransmitter Agents; C497604:SNCA protein, human; D051844:alpha-Synuclein; D014446:Tyrosine 3-Monooxygenase