title: Carbachol-induced in vitro secretion of certain human submandibular proteins investigated by mass-spectrometry.
abstract: OBJECTIVE
  To investigate protein content of saliva produced in vitro by samples of human submandibular gland following stimulation with the muscarinic agent carbachol.
  
  
  METHODS
  Tissue samples, obtained at surgery from seven patients and showing normal morphological appearance, were tested for 30 min: in absence of carbachol and atropine; in presence of carbachol (10 microM); in presence of carbachol (10 microM) and atropine (20 microM); or in presence of just atropine (20 microM). Medium was analysed by high-performance liquid chromatography-mass-spectrometry. Neither before nor during surgery were the patients exposed to drug treatments that were likely to influence the in vitro secretion.
  
  
  RESULTS
  Proline-rich proteins (PRP)-1 and -3, peptide PC and PB, statherin, cystatins SN, S1 and S2 were invariably found in control gland tissue medium. Mean concentrations of these proteins/peptides in the medium were non-proportionally elevated following carbachol exposure to the gland tissues. Difference between basal release and carbachol-induced secretion achieved statistical significance as to all the proteins/peptides under study but for statherin. Atropine alone or atropine plus carbachol caused no significant changes compared to the basal release of proteins/peptides.
  
  
  CONCLUSIONS
  In vitro studies on salivary glands make it possible to study protein secretion from individual glands and thus, to reveal the contribution of the various types of gland to protein/peptide content of whole saliva. The disproportional responses to carbachol may imply that the proteins/peptides are not confined to the same cells or to the same intracellular locations and are therefore not secreted as packages at parasympathetic cholinergic activity.
authors.affiliation: Department of Applied Sciences in Biosystems, University of Cagliari, I-09042 Monserrato, Italy.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Cabras
authors.forename: Massimo
authors.initials: M
authors.lastname: Castagnola
authors.forename: Rosanna
authors.initials: R
authors.lastname: Inzitari
authors.forename: Jörgen
authors.initials: J
authors.lastname: Ekström
authors.forename: Michela
authors.initials: M
authors.lastname: Isola
authors.forename: Alessandro
authors.initials: A
authors.lastname: Riva
authors.forename: Irene
authors.initials: I
authors.lastname: Messana
mesh_terms: D000368:Aged; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology*; D018679:Cholinergic Agonists / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018727:Muscarinic Antagonists / Q000494:pharmacology; D012463:Saliva / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013363:Submandibular Gland / Q000187:drug effects* / Q000378:metabolism; D046509:Tissue Culture Techniques
chemical_list: D018679:Cholinergic Agonists; D018727:Muscarinic Antagonists; D012471:Salivary Proteins and Peptides; D001285:Atropine; D002217:Carbachol