This immunoassay kit allows for the in vitro quantitative determination of rat GABA concentrations in tissue homogenates and other biological fluids.

 

γ-Aminobutyric acid(GABA) has been known to function as an autocrine/paracrine signal molecule in addition to its well-known inhibitory neurotransmitter function.Studies on the developing brain and on primary brain cell cultures providede vidence for avariety of GABA functions in periods preceding the formation of synapses.

GABA is a major inhibitory neurotransmitter, the GABAergic transmission being terminated by the rapid Na+/Cl-dependent uptake through GABA transporters. It has been subdivided into neural and glial uptake systems on the basis of pharmacological properties. Recently, molecular cloning studies have identified multiple subtypes of GABA transporters (GAT1, GAT2, GAT3; and betaine GABA transporter (BGT*1). There is ~*0% homology between various GABA transporter subtypes. GABA transporters are predicted to contain *2 potential transmembrane domains. The NH2 and COOH-termini are predicted to be intracellular. Two of the high affinity (Km~*0 uM) rat GABA transporters (GAT2 and GAT3/GAT-B) share higher amino acid identity (*8% and *5%, respectively) with the kidney betaine transporter than with GAT*1 (*2%aa identity). GAT1 and GAT3 have been detected in various parts of the brain while GAT2 is found in many tissues. It appears that GAT1 and GAT3 are involved in distinct GABAergic transmission while GAT2 may be important in non-neural functions.

 

The microtiter plate provided in this kit has been pre-coated with an antibody specific to GABA. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated polyclonal antibody preparation specific for GABA. Next, Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. Then a TMB substrate solution is added to each well. Only those wells that contain GABA, biotin-conjugated antibody and enzyme-conjugated Avidin will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of **0 nm 2 nm. The concentration of GABA in the samples is then determined by comparing the O.D. of the samples to the standard curve.