title: Direct visualization of peptide uptake activity in the central nervous system of the rat.
abstract: Carrier-mediated transport of small peptides and peptidomimetics offers the opportunity for a targeted drug delivery across cell membranes in the central nervous system (CNS). This process is mediated by the proton-coupled transporter PEPT2 which is expressed in glial and choroid plexus cells. In the present studies, an uptake assay was established to visualize directly peptide uptake in intact rat brain slices. Accumulation of a reporter molecule, the fluorophore-labeled dipeptide derivative D-Ala-L-Lys-AMCA, was found in plexus choroideus and glial cells and uptake was inhibited by prototypical PEPT2 substrates, such as glycyl-L-glutamine and cefadroxil. The presence of PEPT2 was confirmed by RT-PCR and Northern blot analysis. This first CNS peptide and drug transport-visualizing assay may be used to examine new compounds which are carried by the proton-driven CNS peptide transporter.
authors.affiliation: Biomedical Research Center, Otto-Heubner-Centre, Charité School of Medicine, Free University Berlin and Humboldt-University, Augustenburger Platz 1 OR1, D-13353 Berlin, Germany.
authors.forename: David A
authors.initials: DA
authors.lastname: Groneberg
authors.forename: Isabel
authors.initials: I
authors.lastname: Rubio-Aliaga
authors.forename: Monika
authors.initials: M
authors.lastname: Nickolaus
authors.forename: Frank
authors.initials: F
authors.lastname: Döring
authors.forename: Axel
authors.initials: A
authors.lastname: Fischer
authors.forename: Hannelore
authors.initials: H
authors.lastname: Daniel
mesh_terms: D000818:Animals; D001692:Biological Transport; D015152:Blotting, Northern; D002490:Central Nervous System / Q000166:cytology / Q000378:metabolism*; D004151:Dipeptides / Q000737:chemistry / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D066298:In Vitro Techniques; D026901:Membrane Transport Proteins / Q000378:metabolism; D009457:Neuroglia / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D027981:Symporters / Q000235:genetics / Q000378:metabolism*
chemical_list: D004151:Dipeptides; D026901:Membrane Transport Proteins; D010455:Peptides; D012333:RNA, Messenger; D027981:Symporters; C093694:hydrogen-coupled oligopeptide transporter PepT2