Pharyngeal Pumping Assay for Quantifying Feeding Behavior in Caenorhabditis elegans

C. elegans is a well-established nematode model organism, with 83% of its genes conserved in humans with translation potential. C. elegans is translucent, with clearly defined cellular organization, and robustly identifiable under a microscope, being an excellent model for studying feeding behavior. Its neuromuscular pharyngeal pump undergoes a pumping motion that can be quantified to study feeding behavior at specific treatment conditions and in genetically modified worms. Understanding the evolutionarily conserved feeding behaviors and regulatory signals is vital, as unhealthy eating habits increase the risk of associated diseases. The current protocol was developed to identify and study evolutionary conserved signals regulating feeding behavior. The protocol described here is very robust in calculating the pumping rate (pumping per minute) as it directly counts the pharyngeal pumping for 30 s. This protocol uses basic laboratory instrumentation, such as a stereomicroscope with an attached camera and a computer with a video program that can be used to count manually. The advantages of studying C. elegans feeding include understanding the genetic basis of feeding regulation, dysregulation of feeding behavior in a disease model, the influence of toxic or environmental substances in feeding behavior, and modulation of feeding behavior by pharmacological agents. Key features • Quantifies pharyngeal pumping, which can be used to study up/downstream signaling in feeding regulation. • Uses a phenotype (pharyngeal pumping) that is easy to score. • Requires only a stereomicroscope with a camera to record the pharyngeal pumping, which can be counted manually.