title: Dopamine, vesicular transporters, and dopamine receptor expression in rat major salivary glands.
abstract: The localization of dopamine stores and the expression and localization of dopamine (DAT) and vesicular monoamine transporters (VMAT) type-1 and -2 and of dopamine D1-like and D2-like receptor subtypes were investigated in rat submandibular, sublingual, and parotid salivary glands by HPLC with electrochemical detection, as well as immunochemical and immunohistochemical techniques. Male Wistar rats of 2 mo of age were used. The highest dopamine levels were measured in the parotid gland, followed by the submandibular and sublingual glands. Western blot analysis revealed DAT, VMAT-1, VMAT-2, and dopamine receptors immunoreactivity in membrane preparations obtained from the three glands investigated. Immunostaining for dopamine and transporters was developed within striated ducts. Salivary glands processed for dopamine receptors immunohistochemistry developed an immunoreaction primarily in striated and excretory ducts. In the submandibular gland, acinar cells displayed strong immunoreactivity for the D2 receptor, while cells of the convoluted granular tubules were negative for both D1-like and D2-like receptors. Parotid glands acinar cells displayed the highest immunoreactivity for both D1 and D2 receptors compared with other salivary glands. The above localization of dopamine and dopaminergic markers investigated did not correspond closely with neuron-specific enolase (NSE) localization. This indicates that at least in part, catecholamine stores and dopaminergic markers are independent from glandular innervation. These findings suggest that rat major salivary glands express a dopaminergic system probably involved in salivary secretion. The stronger immunoreactivity for dopamine transporters and receptors in striated duct cells suggests that the dopaminergic system could regulate not only quality, but also volume and ionic concentration of saliva.
authors.affiliation: Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Camerino Italy;
authors.forename: Daniele
authors.initials: D
authors.lastname: Tomassoni
authors.affiliation: Scuola di Scienze del Farmaco e dei Prodotti della Salute, Università di Camerino, Camerino Italy; and Dipartimento di Scienze Biomediche e Biotecnologiche, Sezione Biochimica Medica, Università di Catania, Catania Italy.
authors.forename: Enea
authors.initials: E
authors.lastname: Traini
authors.affiliation: Scuola di Scienze del Farmaco e dei Prodotti della Salute, Università di Camerino, Camerino Italy; and.
authors.forename: Manuele
authors.initials: M
authors.lastname: Mancini
authors.affiliation: Dipartimento di Scienze Biomediche e Biotecnologiche, Sezione Biochimica Medica, Università di Catania, Catania Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Bramanti
authors.affiliation: Scuola di Scienze del Farmaco e dei Prodotti della Salute, Università di Camerino, Camerino Italy; and.
authors.forename: Syed Sarosh
authors.initials: SS
authors.lastname: Mahdi
authors.affiliation: Scuola di Scienze del Farmaco e dei Prodotti della Salute, Università di Camerino, Camerino Italy; and francesco.amenta@unicam.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Amenta
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D004298:Dopamine / Q000032:analysis*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000032:analysis*; D059290:Dopaminergic Neurons / Q000737:chemistry; D007150:Immunohistochemistry; D008297:Male; D010306:Parotid Gland / Q000737:chemistry; D010751:Phosphopyruvate Hydratase / Q000032:analysis; D017208:Rats, Wistar; D011954:Receptors, Dopamine / Q000032:analysis*; D017447:Receptors, Dopamine D1 / Q000032:analysis; D017448:Receptors, Dopamine D2 / Q000032:analysis; D012469:Salivary Glands / Q000737:chemistry* / Q000294:innervation; D013361:Sublingual Gland / Q000737:chemistry; D013363:Submandibular Gland / Q000737:chemistry; D050493:Vesicular Monoamine Transport Proteins / Q000032:analysis*
chemical_list: D050483:Dopamine Plasma Membrane Transport Proteins; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C493451:Slc18a1 protein, rat; C493454:Slc18a2 protein, rat; D050493:Vesicular Monoamine Transport Proteins; D010751:Phosphopyruvate Hydratase; D004298:Dopamine
keywords: dopamine receptors; immunohistochemistry; neuron-specific enolase; salivary glands; vesicular monoamine transporters