Uptake of valproic acid into rat brain is mediated by a medium-chain fatty acid transporter

The uptake of valproic acid (VPA) from blood into several brain regions was investigated using the "in situ" brain perfusion technique in the rat. The uptake kinetics of VPA exhibited partial saturability and trans-stimulation, which indicate the simultaneous presence of carrier-mediated transport and diffusion. The apparent Michaelis constant for the saturable process ranged from 10mM in the cortical regions to 23.5 mM in the thalamus. The uptake of radiotracer VPA was not inhibited by coperfusion of short-chain (