title: Distribution of choline acetyltransferase immunoreactivity in the alimentary tract of the barnacle Balanus amphitrite (Cirripedia, Crustacea).
abstract: To date only peptidergic innervation has been described in the alimentary tract of barnacles. In the present work the presence and distribution of choline acetyltransferase (ChAT), the acetylcholine (ACh) synthesizing enzyme, was investigated by immunohistochemistry in the alimentary tract of the adult barnacle Balanus amphitrite. Numerous ChAT-immunoreactive (IR) cells and a net of ChAT-IR cytoplasmic processes were localized inside the epithelium of the posterior midgut, close to the basement membrane; no IR nerve endings were detected in the midgut longitudinal and circular muscle bundles. Epithelial neurons or endocrine cells in the gut epithelium have been described in some invertebrate species belonging to different taxa and their peptidergic features are reported in the literature. Our results point out the presence of neuroepithelial cells also in the gut epithelium of barnacles; moreover, for the first time, a cholinergic feature is suggested for this cell type. These data seem to indicate the involvement of ACh in the gut functions of barnacle and suggest that the barnacle alimentary tract is more complex than previously thought and requires further study.
authors.affiliation: LIBiOM, Dipartimento di Biologia, Università di Genova, Viale Benedetto XV 5, I-16132 Genova, Italy. gallus@unige.it
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Gallus
authors.forename: Sara
authors.initials: S
authors.lastname: Ferrando
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Bottaro
authors.forename: Laura
authors.initials: L
authors.lastname: Girosi
authors.forename: Paola
authors.initials: P
authors.lastname: Ramoino
authors.forename: Alberto
authors.initials: A
authors.lastname: Diaspro
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Aluigi
authors.forename: Grazia
authors.initials: G
authors.lastname: Tagliafierro
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D004064:Digestive System / Q000294:innervation* / Q000378:metabolism*; D046569:Neuroepithelial Cells / Q000378:metabolism*; D001468:Thoracica / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D002795:Choline O-Acetyltransferase; D000109:Acetylcholine