Development and Characterization of Pantothenic Acid Transport in Brain

In vitro, the transport of 3H]pantothenic acid into and from rabbit brain slices was studied. In newborn rabbits and throughout development, forebrain and cerebellar slices were able to accumulate and phosphorylate 3H]pantothenic acid comparably to slices from adults. The accumulation and phosphorylation of 3H]pantothenic acid by adult forebrain slices were not decreased by substitution of LiCl for NaCl in the artificial CSF or by addition of short-chain fuels (e.g., 5 mM pyruvate or acetoacetate) to the medium. However, probenecid and ouabain (both 1 mM) and medium-chain fatty acids (e.g., 0.1 mM octanoate, nonanoate, and decanoate) profoundly inhibited 3H]pantothenic acid accumulation by forebrain slices but not intracellular phosphorylation and conversion to 3H]CoA. There in vitro results suggest that brain slices accumulate pantothenic acid by a saturable system (probably facilitated diffusion) that is sensitive to inhibition by probenecid and medium-chain fatty acids.