VAGAL INVOLVEMENT IN DIETARY-REGULATION OF NUTRIENT TRANSPORT

In omnivores, gradual. alterations in dietary nutrient composition are observed. To efficiently absorb dietary nutrients these animals alter intestinal nutrient transporter expression to match the pattern of nu trient intake. This often involves reprogramming the crypt cell to exp ress greater numbers of the relevant transport system. The aim of this study was to determine whether vagal afferents are involved in this a daptive process. Guinea pigs were habituated to a low-carbohydrate die t and then switched to a high-carbohydrate diet. The resultant increas e in glucose transporter expression was assessed by determining rates of glucose transport in jejunal brush-border membrane vesicles. Ablati on of vagal afferents was accomplished by application of capsaicin to exposed cervical vagi and confirmed using Fast blue tracer studies. We found that animals in which vagal afferents were ablated with capsaic in were unable to alter rates of glucose transport in response to an i ncrease in dietary carbohydrate. This suggests that vagal afferents ar e involved in this adaptive process. These findings support a role for the vagus nerve in regulating intestinal transport function, which ma y be important to consider in clinical disease that involves the vagus nerve.