Examining Hindbrain Activation at Multiple Time Points Following a Small Intestinal Intralipid Infusion in Mice

Overview

Obesity and diabetes are life-debilitating health conditions that may lead to life-long health complications. Energy homeostasis is tightly regulated, helping maintain food satiation and satiety that contributes to overall energy intake, and requires significant input from the gastrointestinal tract. Impaired energy homeostasis involves impaired brain signaling due to improper gut sensing and signaling of nutrients, leading to the increased food intake associated with obesity. In this study, we examine the gut-to-brain signaling pathway associated with maintenance of energy homeostasis and nutrient-induced satiation by examining the activation of the nucleus tractus solitarius (NTS) via the neuronal marker, cFos, at 30, 60 and 90 minutes after an intralipid or saline infusion in the small intestine of mice. Intralipid and saline were infused into the small intestine of mice through a surgically-implanted catheter and fixed brain slices were collected for immunofluorescent imaging and analysis. We found that intralipid increases cFos activation in the NTS at all three timepoints, with the greatest increase compared to saline at the 30-minute time point. The results lay the groundwork for future studies looking to target the small intestinal gut-brain signaling pathway and demonstrate the optimal time point for examining neuronal activation following a small intestinal nutrient stimulus.