Amylin and glucose co-activate area postrema neurons of the rat

Glucose is an important metabolic factor controlling feeding behavior. There is evidence that physiologically relevant glucose sensors reside in the caudal hindbrain. The area postrema (AP) in particular, which has been characterized as a receptive site for the anorectic hormone amylin, may monitor blood glucose levels. To determine whether glucose and amylin co-activate the same subset of AP neurons, we performed extracellular single unit recordings from a rat AP slice preparation. In 53% of all AP neurons tested (n=32), the activity was positively correlated to the glucose concentration. Interestingly, there was a coincidental sensitivity (94%) of AP neurons to glucose and amylin, which exerted excitatory effects on these cells. We conclude that the co-sensitivity of AP neurons to glucose and amylin, both increasing in response to food intake, points to the AP as an important hindbrain center for the integration of the metabolic and hormonal control of nutrient intake.