gamma. -Aminobutyric acid transport in reconstituted preparations from rat brain: coupled sodium and chloride fluxes

Journal Article · Tue Jan 12 00:00:00 EST 1988 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00401a003· OSTI ID:5357875

Keynan, S; Kanner, B I

Transport of ..gamma..-aminobutyric acid (GABA) is electrogenic and completely depends on the presence of both sodium and chloride ions. These ions appear to be cotransported with ..gamma..-aminobutyric acid through its transporter. Using proteoliposomes into which a partially purified ..gamma..-aminobutyric acid transporter preparation was reconstituted. The authors have been able-for the first time-to provide direct evidence for sodium- and chloride-coupled ..gamma..-aminobutyric acid transport. This has been done by measuring the fluxes of /sup 22/Na/sup +/, /sup 36/Cl/sup -/, and (/sup 3/H)GABA. These fluxes have the following characteristics: There are components of the net fluxes of sodium and chloride that are ..gamma..-aminobutyric acid dependent. The sodium flux is chloride dependent. The chloride flux is sodium dependent. Thus, the ..gamma..-aminobutyric acid dependent sodium and chloride fluxes appear to be catalyzed by the transporter. Using these fluxes they have attempted to determine the stoichiometry of the process. They measured the initial rate of sodium-dependent ..gamma..-aminobutyric acid fluxes and that of ..gamma..-aminobutyric acid dependent sodium fluxes. Similarly, they measured the stoichiometry between chloride and ..gamma..-aminobutyric acid. The half-maximal effect obtained when the ..gamma..-aminobutyric acid concentration dependence of Cl/sup -/ and Na/sup +/ transport is determined is much higher than the known K/sub m/ of this system. Reexamination of the kinetics of ..gamma..-aminobutyric acid transport reveals that there are two transport systems for it. The sodium, chloride, and ..gamma..-aminobutyric acid fluxes probably originate from the low-affinity transporter.

• Research Organization: Hebrew Univ., Jerusalem, Israel
• OSTI ID: 5357875
• Journal Information: Biochemistry; (United States), Vol. 27:1
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
AMINOBUTYRIC ACID
UPTAKE
MEMBRANE TRANSPORT
BIOCHEMICAL REACTION KINETICS
TRITIUM COMPOUNDS
BRAIN
CHLORINE 36
ION EXCHANGE CHROMATOGRAPHY
LIPOSOMES
RATS
SODIUM 22
SODIUM CHLORIDES
STOICHIOMETRY
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
AMINO ACIDS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
CHLORIDES
CHLORINE COMPOUNDS
CHLORINE ISOTOPES
CHROMATOGRAPHY
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
HALIDES
HALOGEN COMPOUNDS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
MAMMALS
NERVOUS SYSTEM
NEUROREGULATORS
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
RADIOISOTOPES
REACTION KINETICS
RODENTS
SEPARATION PROCESSES
SODIUM COMPOUNDS
SODIUM ISOTOPES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques