Related Experiment Video
Updated: May 25, 2026

Methods for the Discovery of Novel Compounds Modulating a Gamma-Aminobutyric Acid Receptor Type A Neurotransmission
Published on: August 16, 2018
Coupling between GABA(A)-R ligand-binding activity and membrane organization in β-cyclodextrin-treated synaptosomal
Anahí V Turina1, Shirley Schreier, María A Perillo
1IIBYT, CONICET - Biofísica-Química, Departamento de Química, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina. aturina@efn.uncor.edu
Abstract:
Correlations between GABA(A) receptor (GABA(A)-R) activity and molecular organization of synaptosomal membranes (SM) were studied along the protocol for cholesterol (Cho) extraction with β-cyclodextrin (β-CD). The mere pre-incubation (PI) at 37°C accompanying the β-CD treatment was an underlying source of perturbations increasing [(3)H]-FNZ maximal binding (70%) and K (d) (38%), plus a stiffening of SMs' hydrocarbon core region. The latter was inferred from an increased compressibility modulus (K) of SM-derived Langmuir films, a blue-shifted DPH fluorescence emission spectrum and the hysteresis in DPH fluorescence anisotropy (A (DPH)) in SMs submitted to a heating-cooling cycle (4-37-4°C) with A (DPH,heating) < A (DPH,cooling). Compared with PI samples, the β-CD treatment reduced B (max) by 5% which correlated with a 45%-decrement in the relative Cho content of SM, a decrease in K and in the order parameter in the EPR spectrum of a lipid spin probe labeled at C5 (5-SASL), and significantly increased A (TMA-DPH). PI, but not β-CD treatment, could affect the binding affinity. EPR spectra of 5-SASL complexes with β-CD-, SM-partitioned, and free in solution showed that, contrary to what is usually assumed, β-CD is not completely eliminated from the system through centrifugation washings. It was concluded that β-CD treatment involves effects of at least three different types of events affecting membrane organization: (a) effect of PI on membrane annealing, (b) effect of residual β-CD on SM organization, and (c) Cho depletion. Consequently, molecular stiffness increases within the membrane core and decreases near the polar head groups, leading to a net increase in GABA(A)-R density, relative to untreated samples.
More Related Videos
07:51Inhibitory Synapse Formation in a Co-culture Model Incorporating GABAergic Medium Spiny Neurons and HEK293 Cells Stably Expressing GABAA Receptors
Published on: November 14, 2014
11:57Using an α-Bungarotoxin Binding Site Tag to Study GABA A Receptor Membrane Localization and Trafficking
Published on: March 28, 2014
Related Concept Videos
G-protein Coupled Receptors
ER Retrieval Pathway
The ER uses many checkpoints to prevent the entry of incorrectly folded or a resident protein as cargo onto a transport vesicle. These mechanisms...
GPCRs Regulate Adenylyl Cylase Activity
Two...
Activation and Inactivation of G Proteins
Ligand-Gated Ion Channel Receptor: Gating Mechanism
GPCR Desensitization