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| Genes | GABRA1, GABRB3, GABRG2 (multiple subunits) |
| UniProt |
GABRA1, GABRB3 |
| PDB |
6HUP, 5OS0 |
| Mol. Weight |
~50-60 kDa per subunit |
| Localization |
Postsynaptic membrane, neuronal plasma membrane |
| Family |
Cys-loop ligand-gated ion channel family |
| Ligands |
GABA (agonist), Benzodiazepines (positive modulators), Bicuculline (antagonist) |
| Diseases |
Alzheimer's Disease, Parkinson's Disease, ALS, Epilepsy, Anxiety Disorders |
GabaA< Sub> Receptor is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
The GABAA receptor (GABAAR) is the primary inhibitory neurotransmitter receptor in the mammalian brain. It belongs to the Cys-loop family of ligand-gated ion channels and mediates fast synaptic inhibition. Dysfunction of GABAA receptors is implicated in various neurological and neurodegenerative disorders, making them important therapeutic targets.[1]
¶ Structure and Subunit Composition
GABAA receptors are pentameric assemblies composed of multiple subunits:
- α subunits (α1-α6): Determine benzodiazepine sensitivity
- β subunits (β1-β3): Bind GABA
- γ subunits (γ1-γ3): Required for benzodiazepine binding
- δ, ε, θ, π subunits: Additional regulatory subunits
- α1β2γ2 (~60% of cortical receptors): Sedative actions
- α2β3γ2 (~15-20%): Anxiolytic actions
- α3β3γ2: Memory and cognition
- α5β3γ2: Hippocampal, learning and memory
GABAA receptors mediate fast inhibitory neurotransmission:
- GABA binding opens chloride channel
- Hyperpolarizes neurons (in adults)
- Reduces neuronal firing rates
- Controls network excitability[2]
These receptors regulate:
- Cortical oscillations
- Memory consolidation
- Anxiety and fear circuits
- Motor coordination
Prevents excessive neuronal excitation:
- Limits seizure spread
- Protects against excitotoxicity
- Maintains balance with glutamatergic signaling
GABAA receptor changes in AD:
- Reduced receptor expression in hippocampus
- Altered subunit composition
- Contributes to network hyperexcitability
- May underlie seizures in AD[3]
In PD:
- GABAergic dysfunction in basal ganglia
- Altered inhibitory signaling
- Related to levodopa-induced dyskinesias
- GABAA modulators being explored[4]
In ALS:
- Motor neuron hyperexcitability involves GABAergic deficits
- Reduced inhibitory neurotransmission
- Altered chloride homeostasis
GABAA receptors are central to epilepsy:
- Loss of inhibitory function
- Mutations cause genetic epilepsies
- Target of anti-epileptic drugs
- Benzodiazepines: Positive allosteric modulators (sedative, anxiolytic)
- Barbiturates: Direct channel openers
- Propofol: General anesthetic
- Ethanol: Positive modulator
- Subunit-selective modulators: Target specific α subunits
- Benzodiazepine site agonists: Novel compounds
- Allosteric modulators at non-benzodiazepine sites
- Olsen RW, Sieghart W. (2008). GABAA receptors: subtypes provide diversity of function and pharmacology. Neuropharmacology 56(1):141-148.
- Farrant M, Nusser Z. (2005). Variations on an inhibitory theme: phasic and tonic activation of GABAA receptors. Nat Rev Neurosci 6(3):215-229.
- Limon A, et al. (2012). GABAA receptor alterations in Alzheimer's disease. J Alzheimer's Dis 32(1):1-14.
- Gardoni P, et al. (2016). GABAA receptors in dopaminergic transmission. J Neural Transm (Vienna) 123(7):741-749.
The study of GabaA< Sub> Receptor has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.