High-resolution electrophoretic analysis of rat parotid salivary proteins

Silver staining and high-resolution electrophoretic methods have been used to compare the protein composition of rat parotid saliva evoked in response to (i) parasympathetic stimulation (including the nonadrenergic, noncholin ergic, atropine-associated secretion), (ii) sympathetic stimulation, or (ii i) the infusion of neuropeptides with secretagogue activity (substance P, c alcitonin gene-related peptide, neuropeptide Y, or vasoactive intestinal pe ptide). The different stimuli influenced the protein concentration and flow rate of the evoked secretion but had little effect upon the protein compos ition of the saliva. In contrast to earlier studies using sodium dodecyl su lfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Coomassie blue stai ning, the combination of silver staining and two-dimensional electrophoresi s (2-DE) revealed many newly detected proteins. The results indicate that t he protein composition of rat parotid saliva is more complex than previousl y reported but is unaffected by the mode of stimulation.