Functional and proteomic analysis of submandibular saliva in rats exposed to chronic stress by immobilization or constant light.

ALTERMAN A, MATHISON R, CORONEL CE, STROPPA MM, FINKELBERG AB, GALLARÁ RV.

ARCHIVES OF ORAL BIOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2012 p. 663 - 669

0003-9969

Objective: In this study, we have evaluated the effects of stress on functional and proteomicchanges in submandibular saliva of rats.Design: Male adult rats were divided in three groups: IMO (2 h/day of immobilization for 7days), LL (constant light during 20 days), C (unstressed controls submitted to 14 h light?10 hdark cycle). Body weight, food intake and the dry weight of submandibular gland wererecorded. Saliva samples, collected under anaesthesia following i.p. administration ofisoproterenol and pilocarpine (5 mg/kg), were assayed for total proteins (TP), amylaseactivity and SDS-PAGE electrophoresis.Results: Body weight, food intake and the dry weight of submandibular gland of IMO ratswere 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 (mg protein/mg saliva/mg of drytissue) and amylase activity output (AU/mg of saliva/mg of dry tissue) in IMO were significantlyhigher than in C and LL animals. The electrophoretic pattern of saliva proteins of LLrats, revealed the absence of a protein band of approximately 25 kDa. This band wascomposed by the common salivary protein-1 and a prolactin-induced protein as identifiedby peptide mass fingerprinting.Conclusions: Differences in body weight and food intake between IMO and LL might beattributed to the sort and intensity of stressors stimuli. The changes in the volume of secretedsaliva could be a compensatory mechanism in response to stressors. The increase of totalprotein in IMO rats and the absence of 25 kDa proteins in LL, would suggest that thesubmandibular glands respond to the sympathetic nervous system stimuli induced by thestress with an increase of activity of the sympathetic nerves in IMO and a reduction in LL rats.