The interface between the blood and brain is vital for the protection of neurological processes. A key regulatory mechanism of the blood-brain border (BBB) is the circadian rhythm, an intrinsic timekeeping system that maintains 24-h rhythms. At the BBB, the endothelial cell clock has been implicated in time-of-day differences in removal of drugs from the brain; however, pharmacologic modulation of the BBB clock remains unexplored. To investigate circadian dynamics in the BBB, we isolated murine ...