title: Functional and proteomic analysis of submandibular saliva in rats exposed to chronic stress by immobilization or constant light.
abstract: OBJECTIVE
  In this study, we have evaluated the effects of stress on functional and proteomic changes in submandibular saliva of rats.
  
  
  METHODS
  Male adult rats were divided in three groups: IMO (2 h/day of immobilization for 7 days), LL (constant light during 20 days), C (unstressed controls submitted to 14 h light-10h dark cycle). Body weight, food intake and the dry weight of submandibular gland were recorded. Saliva samples, collected under anaesthesia following i.p. administration of isoproterenol and pilocarpine (5 mg/kg), were assayed for total proteins (TP), amylase activity and SDS-PAGE electrophoresis.
  
  
  RESULTS
  Body weight, food intake and the dry weight of submandibular gland of IMO rats were lower than those of C and LL groups. The salivary volumes secreted in IMO and LL rats, were significantly higher than in controls. The TP output (μg protein/μg saliva/mg of dry tissue) and amylase activity output (AU/μg of saliva/mg of dry tissue) in IMO were significantly higher than in C and LL animals. The electrophoretic pattern of saliva proteins of LL rats, revealed the absence of a protein band of approximately 25 kDa. This band was composed by the common salivary protein-1 and a prolactin-induced protein as identified by peptide mass fingerprinting.
  
  
  CONCLUSIONS
  Differences in body weight and food intake between IMO and LL might be attributed to the sort and intensity of stressors stimuli. The changes in the volume of secreted saliva could be a compensatory mechanism in response to stressors. The increase of total protein in IMO rats and the absence of 25 kDa proteins in LL, would suggest that the submandibular glands respond to the sympathetic nervous system stimuli induced by the stress with an increase of activity of the sympathetic nerves in IMO and a reduction in LL rats.
authors.affiliation: Cátedras de Química Biológica A y de Fisiología, Facultad de Odontología, Universidad Nacional de Córdoba, Argentina. alejandroalterman@gmail.com
authors.forename: A
authors.initials: A
authors.lastname: Alterman
authors.forename: R
authors.initials: R
authors.lastname: Mathison
authors.forename: C E
authors.initials: CE
authors.lastname: Coronel
authors.forename: M M
authors.initials: MM
authors.lastname: Stroppa
authors.forename: A B
authors.initials: AB
authors.lastname: Finkelberg
authors.forename: R V
authors.initials: RV
authors.lastname: Gallará
mesh_terms: D000681:Amylases / Q000032:analysis; D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight; D004591:Electrophoresis, Polyacrylamide Gel; D008027:Light; D008297:Male; D013058:Mass Spectrometry; D009929:Organ Size; D040901:Proteomics; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical; D012463:Saliva / Q000737:chemistry*; D012471:Salivary Proteins and Peptides / Q000032:analysis*; D013312:Stress, Physiological; D013363:Submandibular Gland / Q000378:metabolism; D013564:Sympathetic Nervous System / Q000503:physiopathology*
chemical_list: D012471:Salivary Proteins and Peptides; D000681:Amylases