The Role Of Hormone Receptors During And After Digestion

The goal of this study is to understand how the ghrelin receptor and motilin receptor regulate normal gut motility. Previous work suggests that the ghrelin receptor is activated before a meal to cause hunger, and during a meal to cause stomach emptying. After a meal, the motilin receptor is activated and causes “sweeping” movements that clear undigested debris from the gut. Both receptors are being studied in order to develop improved treatments for intestinal diseases. In my studies, I am using zebrafish as a model for human gut motility disorders. I developed and tested an assay that allows the observation of gut movements and emptying in live zebrafish. I found that emptying the intestine after a meal required 4 hours (hrs). By contrast, when fish were maintained at 20oC to slow metabolism, emptying the intestine was delayed and required 7 hrs. Treatment with MgSO4 to speed up gut movements resulted in faster emptying, within 3 hrs. This is proof-of-principle that this assay can detect decreases and increases in gut motility. This approach will allow myself to demonstrate the roles of these receptors in a genetically-tractable vertebrate model.