Electrogenic uptake of gamma-aminobutyric acid by a cloned transporter expressed in Xenopus oocytes.
GAT-1, a gamma-aminobutyric acid (GABA) transporter cloned from rat brain, was expressed in Xenopus oocytes. Voltage-clamp measurements showed concentration-dependent, inward currents in response to GABA (K0.5 4.7 microM). The transport current required extracellular sodium and chloride ions; the Hill coefficient for chloride was 0.7, and that for sodium was 1.7. Correlation of current and [3H]GABA uptake measurements indicate that flux of one positive charge occurs per molecule of GABA transported. Membrane hyperpolarization from -40 to -100 mV increased the transport current approximately 3-fold. The results indicate that the transport of one molecule of GABA involves the co-transport of two sodium ions and one chloride ion.
Kavanaugh
M P
MP
Vollum Institute, Oregon Health Sciences University, Portland 97201.
Arriza
J L
JL
North
R A
RA
Amara
S G
SG
D000818:Animals; D001693:Biological Transport, Active; D002352:Carrier Proteins / Q000378:metabolism*; D002712:Chlorides / Q000502:physiology; D003001:Cloning, Molecular; D050485:GABA Plasma Membrane Transport Proteins; D066298:In Vitro Techniques; D008564:Membrane Potentials; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D009865:Oocytes; D027361:Organic Anion Transporters; D012964:Sodium / Q000502:physiology; D014982:Xenopus laevis; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D002352:Carrier Proteins; D002712:Chlorides; D050485:GABA Plasma Membrane Transport Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D027361:Organic Anion Transporters; C493415:Slc6a1 protein, rat; D005680:gamma-Aminobutyric Acid; D012964:Sodium