Scientists have developed a novel concept of a nose-to-brain system for the clinical application of neuropeptides. They developed a derivative of glucagon-like peptide-2 and found that when administered intranasally, it is efficiently delivered through the trigeminal nerve to the site of action and exhibits antidepressant-like effects. This is the first demonstration in the world that intranasally administered neuropeptides reach the brain (hippocampus and hypothalamus) via neurons.