Circadian Clock in Blood–Brain Barrier May Decide Best Drug Dosing Times

Keeping to a regular diurnal rhythm, the cell–cell junctions of the blood–brain barrier (BBB) tighten and loosen, tighten and loosen, on and on, admitting foreign substances such as drugs more readily during the night, but maintaining a more formidable barrier during the day. While scientists have long suspected as much, they have only recently isolated the circadian mechanism that regulates the BBB’s daily permeability.The mechanism, say its discoverers, could help clinicians