GABA Receptors Wiki | Function, Classification, Location, Repair, Anxiety

GABA receptors Classification

3 major subtypes of trans-membrane proteins

GABA A - 5 subunits, coassemble to form an integral, involves ionotropic chloride channel

GABA B - it is single, G protein-coupled, metabotropic receptor

GABA C - ligand-gated chloride channel, function and pharmaco properties are different from GABA A & B

GABA A Receptors

GABA A receptors is a glycoprotein pentamer belonged to of ligand-gated ion channelfamily

The GABA A receptor-chloride ionophore complex is made of 5 subunits, alfa, beta and gamma that co-assemble to form an integral chloride channel

There are 6 subtypes of alfa, and 3 each of beta and gamma

GABA binds to a site on the alfa or beta subunit

The receptor also contains binding sites for benzodiazepines, barbiturates and steroids such as progesterone (distinct from the GABA-binding site)

Functional Diversity of the GABA A Receptor Subunits

alfa1 subunit - containing GABA A receptors: sedation

alfa2 subunit - anxiolysis

alfa3 subunit - processing of sensory motor information related to a schizophrenia endophenotype

alfa4 subunit - sedative, hypnotic and anesthetic effects of some agents in the thalamus

alfa5 subunit - (extrasynaptic): associative temporal and spatial memory by inhibitory modulation of activities in the hippocampus

beta3 subunit - sedation, hypnosis, and anesthesia

GABA Function and Distribution

Inhibitory neurotransmitter that modulate chloride anion permeability

Widely distributed thoughout central nervous system

Local inhibitory action, therefore rapidly alters neuronal output

GABA is responsible for overall level of inhibitory tone in the brain

GABA binds to GABA A receptors --> causes conformational changes --> open the chloride ion channel --> lead to neuronal membraine hyperpolarization --> inhibitory neurotransmission in the CNS