title: Localization of α7 nicotinic acetylcholine receptor mRNA and protein within the cholinergic anti-inflammatory pathway.
abstract: Electrical stimulation of the vagus nerve attenuates tumor necrosis factor (TNF) synthesis by macrophages and reduces the systemic inflammatory response. Current evidence suggests that the α7 nicotinic acetylcholine receptor present in the celiac/superior mesenteric ganglia is a key component in vagus nerve signaling to the spleen; however, there is currently no direct anatomical evidence that the α7 receptor is present in the murine celiac/superior mesenteric ganglia. Our study addresses this deficiency by providing anatomical evidence that the α7 receptor is expressed within the celiac/superior mesenteric ganglia and splenic nerve fibers using immunohistochemistry and quantitative polymerase chain reaction (qPCR). α7 receptor mRNA is highly expressed in the celiac/superior mesenteric ganglia and at low levels in the spleen compared to the brain. Double-labeling for α7 and tyrosine hydroxylase shows that α7 receptor protein is present on noradrenergic neurons within the ganglia and prejunctionally on noradrenergic nerve fibers within the spleen. The α7 receptor in the ganglia provides a possible location for the action of α7-selective agonists, while prejunctional α7 receptor expressed on splenic nerves may induce an increase in norepinephrine release in a positive feedback system enhanced by lymphocyte-derived acetylcholine.
authors.affiliation: Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Downs
authors.affiliation: Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Bond
authors.affiliation: Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA. Electronic address: hoover@etsu.edu.
authors.forename: D B
authors.initials: DB
authors.lastname: Hoover
mesh_terms: D000818:Animals; D005728:Ganglia, Sympathetic / Q000276:immunology / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D015213:Neuroimmunomodulation / Q000502:physiology*; D009474:Neurons / Q000276:immunology / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction; D013154:Spleen / Q000276:immunology / Q000378:metabolism*; D064569:alpha7 Nicotinic Acetylcholine Receptor / Q000096:biosynthesis*
chemical_list: D012333:RNA, Messenger; D064569:alpha7 Nicotinic Acetylcholine Receptor
keywords: celiac ganglia; cholinergic anti-inflammatory pathway; spleen; superior mesenteric ganglion; sympathetic innervation; α7 nicotinic acetylcholine receptor