GAT2/BGT-1 as a system responsible for the transport of gamma-aminobutyric acid at the mouse blood-brain barrier.
J Cereb Blood Flow Metab
; 21(10): 1232-9, 2001 Oct.
Article
en En
| MEDLINE
| ID: mdl-11598501
ABSTRACT
In this study, the gamma-aminobutyric acid (GABA) transporter at the blood-brain barrier (BBB) was identified by reverse transcription-polymerase chain reaction (RT-PCR), Western blot, and immunostaining analysis, and the transport mechanism was characterized using a conditionally immortalized mouse brain capillary endothelial cell line (TM-BBB) as an in vitro model of the BBB. gamma-Aminobutyric acid transport was studied by the cellular uptake of [ 3 H]GABA. [3H]GABA uptake by TM-BBB cells was Na (+)-, Cl(-)-, and concentration-dependent. The corresponding Michaelis-Menten constant was 679 +/- 80 micromol/L and the maximal uptake rate was 4,790 +/- 494 pmol/(mg protein x 5 minutes). [3H]GABA uptake by TM-BBB cells was significantly inhibited by betaine, beta-alanine, nipecotic acid, taurine, and quinidine, whereas probenecid, L-proline, creatine, and glycine had no effect. This type of inhibition is consistent with the predominant involvement of the GAT2/BGT-1 transporter in TM-BBB cells. RT-PCR analysis showed that GAT2/BGT-1 mRNA was expressed in TM-BBB cells, whereas Western blot analysis showed that TM-BBB cells and mouse brain capillaries express GAT2/BGT-1 protein. Moreover, confocal immunofluorescent microscopy of dual-labeled mouse brain sections demonstrated the colocalization of GAT2/BGT-1 and P-glycoprotein, a BBB-specific marker, on brain capillaries labeled with anti-GAT2/BGT-1 antibody and anti-P-glycoprotein antibody, respectively. These results are evidence that GAT2/BGT-1 is expressed at the BBB and is involved in GABA transport across the BBB.
Buscar en Google
Bases de datos:
MEDLINE
Asunto principal:
Proteínas de Transporte de Membrana
/
Barrera Hematoencefálica
/
Transportadores de Anión Orgánico
/
Ácido gamma-Aminobutírico
Límite:
Animals
Idioma:
En
Revista:
J Cereb Blood Flow Metab
Año:
2001
Tipo del documento:
Article
País de afiliación:
Japón