title: Glial cells express multiple ATP binding cassette proteins which are involved in ATP release.
abstract: Rat brain astrocyte and microglia cultures express different members of ATP-binding-cassette (ABC) proteins. RT-PCR analysis showed that astrocytes are equipped with P-glycoprotein (mdr1a, mdr1b), multidrug resistance-associated-protein (mrp1, mrp4, mrp5) and cystic fibrosis transmembrane conductance regulator (CFTR). No transcripts for mrp5 and CFTR were detected in microglia. The ABC protein functional activities are shown by the following results: (i) cyclosporin A (50 microM), verapamil (50 microM), probenecid (1 mM) or sulfinpyrazone (2 mM) enhanced [3H]vincristine accumulation; (ii) cyclosporin A or verapamil but not probenecid or sulfinpyrazone enhanced [3H]digoxin accumulation; (iii) glibenclamide (100 microM) inhibited 36Cl efflux from astrocytes. ATP release from glial cells was inhibited by the pretreatment with ABC protein inhibitors indicating that ABC proteins are involved in nucleotide efflux from glial cells which represent the main source of cerebral extracellular purines.
authors.affiliation: Department of Biomedical Sciences, School of Medicine, University of Chieti, Italy. p.ballerini@dsb.unich.it
authors.forename: Patrizia
authors.initials: P
authors.lastname: Ballerini
authors.forename: Patrizia
authors.initials: P
authors.lastname: Di Iorio
authors.forename: Renata
authors.initials: R
authors.lastname: Ciccarelli
authors.forename: Eleonora
authors.initials: E
authors.lastname: Nargi
authors.forename: Iolanda
authors.initials: I
authors.lastname: D'Alimonte
authors.forename: Ugo
authors.initials: U
authors.lastname: Traversa
authors.forename: Michel P
authors.initials: MP
authors.lastname: Rathbone
authors.forename: Francesco
authors.initials: F
authors.lastname: Caciagli
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000378:metabolism; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism; D005333:Fetus; D017628:Microglia / Q000378:metabolism*; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism; D011493:Protein Kinase C / Q000187:drug effects / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D018528:ATP-Binding Cassette Transporters; D000255:Adenosine Triphosphate; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D011493:Protein Kinase C; D011500:Protein Synthesis Inhibitors