The Role of Orosensory and Post-Ingestive Feedback in Salivary Protein Production

Variation in bitter taste perception plays a crucial role in dietary choice and much research has been done to better understand the factors that cause variation in bitter taste perception. One factor that may cause variation in bitter taste perception is saliva. Salivary protein expression can be altered by diet [11]. For example, while we know that tannin diets cause the upregulation of proline-rich proteins (PRPs) [11], it is still unclear if it is oral exposure, gastric exposure or tannin exposure at both sites that is responsible for the upregulation of PRPs. In this study we were able to better understand how salivary proteins are induced by analyzing the saliva of rats treated with oral exposure alone (via oral infusion), gastric exposure alone (via gastric infusion), or exposure at both sites with a tannic acid solution. Our preliminary analyses demonstrate a subset of proteins that are upregulated by dietary exposure are upregulated by oral exposure alone (35kDa, 25kDa and 19kDa) demonstrating that for these proteins oral exposure is sufficient. Furthermore, as these proteins are not upregulated by gastric exposure, we believe oral exposure is necessary for upregulation to occur. In contrast, for a protein band at 18kDa, oral exposure did not effect protein expression while gastric exposure alone was sufficient and necessary in order for upregulation to occur. ; Keywords: Salivary Proteins, Neuroscience, Taste, Bitter, Taste Perception ; Submitted Note: A Thesis submitted to the Department of Psychology in partial fulfillment of the requirements for the degree of Honors in the Major. ; Degree Awarded: Spring Semester, 2014. ; Date of Defense: April 14, 2104.