GABAA Receptor Alpha 1 Beta 3 Gamma 2
Family:
GABA Receptors (Cys-loop ligand-gated ion channels)
Subgroups:
The GABA receptor family has further been divided into GABAA, GABAB and GABAA-ρ (also called GABAC) receptors.
Topology:
As typical for Cys-loop receptors, generally four transmembrane spanning domains TM1-TM4 form one receptor subunit, five or four subunits form a pore, several heteromeric combinations are known.
GABAA: Oligomerization of typically five subunits, heteromeric combinations are known of α subunits (GABRA1 - GABRA6), β subunits (GABRB1 - GABRB3) and γ subunits (GABRG1 - GABRG3), as well as δ (GABRD), an ε (GABRE), a π (GABRP), and a θ (GABRQ). The most common type is (α1)2(β2)2(γ2), minimal requirement is the inclusion of α and β subunits.
GABAB: Heterodimer (GABBR1, GABBR2)
GABAA-ρ: Oligomerization of five subunits, heteromeric combinations of three GABAA-ρ subunits are known (GABRR1, GABRR2, GABRR3)
Regulation and Function:
GABAA and GABAA-ρ receptors are ligand-gated ion channels (ionotropic receptors); whereas GABAB receptors are G protein-coupled receptors (metabotropic receptors). All respond to the neurotransmitter gamma-aminobutyric acid (GABA), the main inhibitory transmitter in the mammalian CNS.
Data and Applications
Application Notes
GABAA: Further Readings
Patchliner data and applications:
Cells were kindly provided by AstraZeneca.
The top images show dose dependent block of GABAA currents by bicuculline. The IC50 was determined as 1.2 ± 0.2 μM (n=11). The lower graph shows the positive modulation of glycine activation of hGlyRα1. Here, six co-applications of 20 μM glycine and increasing concentrations of a positive modulator are shown.
Patchliner data and applications:
Ligand gated ion channels often display receptor desensitization. A method was developed to minimize ligand exposure times and intervals between ligand exposures. The pipette first aspirates buffer, then compound. When expelling this stack, the cell is first exposed to ligand and then buffer. Exposure times as low as 400 ms are possible with this method. A GABA dose response curve, aquired in this manner, is shown on the left.
SyncroPatch 96 (a predecessor model of SyncroPatch 384PE) data and applications:
Shown is a raw current response of a HEK293 cell expressing GABAA receptors to initial exposure to GABA, followed by joint exposure to GABA and diazepam (as indicated). Solutions were stacked (layered) in the pipette to achieve brief exposure times.
SyncroPatch 96 (a predecessor model of SyncroPatch 384PE) data and applications:
Increasing concentrations of GABA were applied to each cell. Cells were from frozen stocks and were prepared for a FliPR experiment running alongside.
The corresponding online analysis of this experiment is shown in the data set "GABAA - CRC Analysis".
Patchliner data and applications:
Cells were kindly provided by Cellular Dynamics.
Activation of GABAA receptor currents by 30 μM GABA and partial block of the current response by 1 μM bicuculline. Bicuculline was pre-applied for at least 30 s before co-application with GABA (30 μM). Approximately 50% of the current was blocked by 1 μM bicuculline.
SyncroPatch 96 (a predecessor model of SyncroPatch 384PE) data and applications:
Online analysis results of the dose response curves were obtained with a few mouse clicks. The color code of the online analysis helps to visualize different concentrations applied.
The corresponding data traces is shown in the data set "GABAA - Dose Response Curves".
Patchliner publication in Biotechnology Letters (2021)
Authors:
Shekdar K., Langer J., Venkatachalan S., Schmid L., Anobile J., Shah P., Lancaster A., Babich O., Dedova O., Sawchuck D.
SyncroPatch 96 (a predecessor model of the SyncroPatch 384i) Publication in Journal of Vascular Research (2020)
Authors:
Yim P.D., Gallos G., Lee-Kong S.A., Dan W., Wu A.D., Xu D., Berkowitz D.E., Emala C.W.
SyncroPatch 384PE (a predecessor model of SyncroPatch 384i) publication in Journal of Lab Automation (2016)
Authors:
Obergrussberger A., Brüggemann A., Goetze T.A., Rapedius M., Haarmann C., Rinke I., Becker N., Oka T., Ohtsuki A., Stengel T., Vogel M., Steindl J., Mueller M., Stiehler J., George M., Fertig N.
Patchliner,
SyncroPatch 384PE (a predecessor model of SyncroPatch 384i) and
CardioExcyte 96 publication in Channels (2015)
Authors:
Obergrussberger A., Stölzle-Feix S., Becker N., Brüggemann A., Fertig N., Möller C.
Port-a-Patch publication in Nature (2014)
Authors:
Miller P.S., Aricescu A.R.
Patchliner publication in Journal of Biomolecular Screening (2012)
Authors:
Haythornthwaite A, Stoelzle S, Hasler A, Kiss A, Mosbacher J, George M, Brüggemann A, Fertig N.
Port-a-Patch and
Patchliner publication in Combinatorial Chemistry & High Throughput Screening (2009)
Authors:
Farre C., Haythornthwaite A., Haarmann C., Stoelzle S., Kreir M., George M., Brüggemann A., Fertig N.
Port-a-Patch and
Patchliner publication in Expert Opinion Therapeutic Targets (2007)
Authors:
Farre C., Stoelzle S., Haarman C., George M., Brueggemann A., Fertig N.
Port-a-Patch and
Patchliner publication in Small Journal (2006)
Authors:
Brüggemann A., Stoelzle S., George M., Behrends J.C., Fertig N.