Three Gastrointestinal Assays

Abstract

Gastrointestinal (GI) functionality relies on the spontaneous, rhythmic and coordinated propagation of muscular contractions in the GI tract, or GI motility. Without these coordinated motor patterns, digestion falters, and results in problems with digestion. Disrupted or un-coordinated motor patterns are associated with altered GI transit times. GI transit is the amount of time necessary for intestinal contents to move through the GI tract. GI transit is measured in patients complaining about abdominal discomfort to determine if discomfort results from a true dysmotility or from idiopathic symptoms. GI transit assays help to determine appropriate treatments but idiopathic symptoms, or pain from an unknown cause, is very common. The zebrafish is an attractive model system for human GI motility because the entire GI tract can be observed in intact zebrafish larva. In current methods, larvae are fed food with a marker substance and movement through the intestine is viewed using a microscope and recorded using a digital camera. However, GI transit time is highly variable. It is possible that this variability is completely normal and results from variable GI physiology. Alternatively, it is possible that the variability is due to the assay. Three distinct GI transit assays have been published. The overall objective for this work is to determine the reliability for each assay and to better understand which assay is most appropriate for future work. The assays will be described and compared, and results comparing the assays will be presented.