Myocardial nerve fibers are preserved in MPTP-treated mice, despite cardiac sympathetic dysfunction.
Recently, we reported a profound depletion of cardiac sympathetic nerve fibers in Parkinson's disease (PD). This cardiac sympathetic denervation is a characteristic hallmark of PD. Cardiac sympathetic dysfunction was also observed in 1-methyl-4-phenyl-1,2,3,6-tetrahydroxypyridine (MPTP)-treated mice, a model of PD. Although binding assay showed a decreased density of norepinephrine transporter (NET) in the hearts of the mice, their histopathological alterations have not been demonstrated. In this study, we investigated hearts of MPTP-treated mice with immunohistochemical method and Western blot analyses. MPTP-treated mice showed significant decreases in the contents of cardiac noradrenaline and dopamine, suggesting the sympathetic dysfunction. Synaptophysin-, tyrosine hydroxylase- or NET-immunoreactive nerve fibers were abundant in the hearts of control mice and MPTP-treated mice, without apparent differences between the two groups. Western blot analyses also showed no difference in the amounts of these proteins. Myocardial nerve fibers were well preserved in MPTP-treated mice, despite apparent cardiac sympathetic dysfunction.
Amino
Takeshi
T
Department of Neurology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu, Tokyo 183-8526, Japan.
Uchihara
Toshiki
T
Tsunekawa
Hiroko
H
Takahata
Kazue
K
Shimazu
Seiichiro
S
Mizusawa
Hidehiro
H
Orimo
Satoshi
S
D000320:Adrenergic Fibers / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001342:Autonomic Nervous System Diseases / Q000503:physiopathology*; D015153:Blotting, Western; D004298:Dopamine / Q000378:metabolism; D006321:Heart / Q000294:innervation*; D007150:Immunohistochemistry; D020267:MPTP Poisoning / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009638:Norepinephrine / Q000378:metabolism; D050484:Norepinephrine Plasma Membrane Transport Proteins / Q000378:metabolism; D016708:Synaptophysin / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D050484:Norepinephrine Plasma Membrane Transport Proteins; D016708:Synaptophysin; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine; D009638:Norepinephrine