Transport of thiamin across the blood-brain barrier of the rat in the absence of aerobic metabolism.

By employing an anaerobic brain perfusion technique the dependency of thiamin transport across the blood-brain barrier upon high-energy phosphate production has been studied. Analysis of the data revealed essentially identical influx kinetics as those previously reported in vivo, the influx being considerably greater than that for the non-transported small molecule mannitol. These results provide for the first time direct evidence that, unlike at other cell surfaces, the influx of thiamin at the blood-brain barrier is independent of energy-yielding metabolism.