Do we swallow the waste from our brain?

Abstract Ferumoxytol an iron oxide nanoparticle was infused into the lateral cerebroventricle of awake rats to follow its movement and clearance from the brain using magnetic resonance imaging. Within minutes the contrast agent could be observed accumulating on the soft palate at the back of the throat. In a subsequent study fluorescent quantum dots were infused into the brain of rats and within 15 min could be observed in the esophagus using microscopy. These imaging studies clearly show the gut is helping to clear waste from the brain.