Forebrain activation induced by postoral nutritive substances in rats.

Recent studies have shown the nutrient-sensing systems transmitting nutritive information from the gut to the brain. However neural activity evoked by ingested dietary nutrients has not been investigated adequately. Using functional magnetic resonance imaging, we demonstrated that rat forebrain responded to intragastric administration of glucose, L-glutamate, and NaCl. These dietary nutrients led to a significant activation in the forebrain regions including nucleus accumbens, hypothalamic area, and limbic system with different timings. These data indicate that several forebrain regions have important roles on perception and process of postingestive nutrient information.