title: Perivascular nerve fiber α-synuclein regulates contractility of mouse aorta: a link to autonomic dysfunction in Parkinson's disease.
abstract: Parkinson's disease and other neurodegenerative disorders associated to changes in alpha-synuclein often result in autonomic dysfunction, most of the time accompanied by abundant expression of this synaptic protein in peripheral autonomic neurons. Given that expression of alpha-synuclein in vascular elements has been previously reported, the present study was undertaken to determine whether alpha-synuclein directly participates in the regulation of vascular responsiveness. We detected by immunohistochemistry perivascular nerve fibers containing alpha-synuclein in the aorta of mice while aortic endothelial cells and muscular fibers themselves did not exhibit detectable levels of this protein. To assess the effect of alpha-synuclein on vascular reactivity, aortic ring preparations obtained from alpha-synuclein-deficient knockout mice and from transgenic mice overexpressing human wild-type alpha-synuclein under the control of the tyrosine hydroxylase-promoter were mounted and equilibrated in organ baths for isometric tension recording. Lack of alpha-synuclein did not modify the relaxant responses to the endothelium-dependent (acetylcholine) and -independent (sodium nitroprusside) vasodilators, but resulted in a greater than normal norepinephrine-induced vasoconstriction along with a lowered response to dopamine, suggesting potential presynaptic changes in dopamine and norepinephrine releases in knockout mice. Overexpression of alpha-synuclein in TH-positive fibers resulted in complex abnormal responses, characterized by lowered acetylcholine-induced relaxation and lowered norepinephrin-induced contraction. Taken together, our data show for the first time that alpha-synuclein is present in sympathetic fibers supplying the murine aorta and provide evidence that changes in alpha-synuclein levels in perivascular fibers play a physiological role in the regulation of vascular function.
authors.affiliation: Departament de Fisiologia, Universitat de València, 46100 Burjassot, Valencia, Spain.
authors.forename: Vannina G
authors.initials: VG
authors.lastname: Marrachelli
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Miranda
authors.forename: José A
authors.initials: JA
authors.lastname: Alabadí
authors.forename: Miguel
authors.initials: M
authors.lastname: Milán
authors.forename: Marifé
authors.initials: M
authors.lastname: Cano-Jaimez
authors.forename: Martina
authors.initials: M
authors.lastname: Kirstein
authors.forename: Enrique
authors.initials: E
authors.lastname: Alborch
authors.forename: Isabel
authors.initials: I
authors.lastname: Fariñas
authors.forename: Francisco
authors.initials: F
authors.lastname: Pérez-Sánchez
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000294:innervation* / Q000502:physiology; D001342:Autonomic Nervous System Diseases / Q000378:metabolism* / Q000503:physiopathology; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009119:Muscle Contraction / Q000187:drug effects / Q000235:genetics; D009131:Muscle, Smooth, Vascular / Q000294:innervation* / Q000502:physiology; D010300:Parkinson Disease / Q000378:metabolism* / Q000503:physiopathology; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism; D017779:Sympathetic Fibers, Postganglionic / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D014661:Vasoconstriction / Q000187:drug effects / Q000235:genetics; D051844:alpha-Synuclein / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D051844:alpha-Synuclein