title: Transport of branched-chain amino acids in brain slices of developing and adult rats.
abstract: The accumulation of labelled leucine, isoleucine and valine by cerebral slices of developing and adult rats was studied. The accumulation increased with age by 15-25%. It was strongly (from 52 to 86%) inhibited by a 100-fold excess of phenylalanine, tryptophan and another branched-chain amino acid, but moderately activated by GABA and glutamate. The inhibitions evoked by leucine and isoleucine were slightly stronger in young than in adult rats. The corresponding 2-oxoacid analogs of leucine, isoleucine and valine were also inhibitory but less effective. The 30-min accumulation of 3H-labelled branched-chain amino acids was ostensibly higher than the increase in their total concentrations in incubated slices, which apparently bespeaks lively homoexchange of endogenous intracellular and labelled extracellular amino acids.
mesh_terms: D000375:Aging; D000596:Amino Acids / Q000494:pharmacology; D000597:Amino Acids, Branched-Chain / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D001921:Brain / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D066298:In Vitro Techniques; D007532:Isoleucine / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014633:Valine / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D000597:Amino Acids, Branched-Chain; D007532:Isoleucine; D005680:gamma-Aminobutyric Acid; D007930:Leucine; D014633:Valine