Feature | GABA-A | GABA-B | GABA-C |
Type | Ionotropic | Metabotropic (GPCR) | Ionotropic |
Channel Type | Cl⁻ (chloride) channel Cl⁻ influx | G-protein coupled: Gi type K⁺ efflux | Cl⁻ (chloride) channel |
Action | Fast inhibitory | Slow & prolonged inhibitory | Slow inhibitory |
Subunits | Pentameric (2α, 2β, γ) | Dimer of GABA-B1 & GABA-B2 subunits | Pentameric (mostly ρ subunits) |
Location | Brain (postsynaptic) | Brain & spinal cord | Retina (mainly) |
Effect | Hyperpolarization | ↓ cAMP | Hyperpolarization |
Drugs Acting On | • Benzodiazepines (GABA-A agonist) • Barbiturates (GABA-A agonist) • Alcohol | Baclofen (GABA- B agonist) | Not affected by |
Clinical Use | • Sedation • Anxiolysis • Anesthesia • Epilepsy | Muscle relaxant (e.g. Baclofen) | Not commonly targeted |
Figure- Pentameric (2α, 2β, γ)
