Carrier-mediated transport of baclofen across monolayers of bovine brain endothelial cells in primary culture.

The mechanism of transport of baclofen, a centrally acting muscle relaxant, across the blood-brain barrier (BBB) was studied using an in vitro model. The model consisted of a monolayer of bovine brain endothelial cells grown in primary culture on a porous regenerated cellulose membrane. The transport of baclofen across the monolayer expressed time and concentration dependency and was saturable. Transport data were corrected for diffusion and fitted to the Michaelis-Menten Vmax model: Km = 58.5 microM, Vmax = 0.23 nmol/min. The results validate the use of the in vitro BBB model as described and support the hypothesis that baclofen penetrates the BBB by means of a carrier-mediated transport system.