Three Universities Collaborate to Build a Plethysmography Rat System for Undergraduate Student Research at a Small Liberal Arts College to Study the Respiratory Biology of WKY

Behavioral inhibition (BI) is a genetically determined trait that affects roughly 33% of the population. These individuals respond to stressful situations differently than non-behaviorally inhibited (NI) individuals. BI is characterized by the tendency to avoid or withdraw from novel situations and is a significant risk factor for anxiety disorders, including PTSD. BI can be studied in humans, and an animal model of BI exists, the Wistar Kyoto (WKY) rats. WKY rats show reduced open-field activity and social interactions and enhanced avoidance and associative learning. Thus, the WKY is an ideal model for studying BI temperament's role in the stress response to CO2 exposure. To study CO2 sensitivity in BI rats, we embarked on a joint project between Carthage College, the University of Northern Colorado, and The Medical College of Wisconsin to build a custom whole-body plethysmograph to study WKY rats during enhanced CO2 breathing and ultimately be able to compare WKY rats to BI humans. To that end, we developed Carthage’s first system to study the respiration of WKY rats. This volume-constant box (airtight food storage container) is 4.2-liter in volume. When measurements are taken, the box is closed with an airtight seal, except for a small controlled leak that stabilizes the internal pressure by allowing for equilibration of slow pressure changes (due to warming up). Pressure transducers measure changes in the box’s pressure and account for potential changes in pressure caused by the pressure changing in the experiment room and breathing. The box is then connected to a reference chamber, which helps stabilize the pressure changes. For our breathing experiments, the plethysmograph will be sealed except for an inflow port (which would feed either room air or varying levels of CO2), an outflow port, and a slow leak to account for pressure changes while the rat inhales and exhales. Using this technique, we will be able to measure baseline ventilation in SD and WKY rats and examine hypercapnic ventilatory responses to varying levels of CO2. (Supported by the Wisconsin Space Consortium Grant Early-Stage Investigator Grant, ESI24_2-0 to SJT) This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.