Component of a heterodimeric G-protein coupled receptor for GABA, formed by GABBR1 and GABBR2 (PubMed:
9872316, PubMed:
9872744, PubMed:
15617512, PubMed:
18165688, PubMed:
22660477, PubMed:
24305054). Within the heterodimeric GABA receptor, only GABBR1 seems to bind agonists, while GABBR2 mediates coupling to G proteins (PubMed:
18165688). Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of down-stream effectors, such as adenylate cyclase (PubMed:
10906333, PubMed:
10773016, PubMed:
10075644, PubMed:
9872744, PubMed:
24305054). Signaling inhibits adenylate cyclase, stimulates phospholipase A2, activates potassium channels, inactivates voltage-dependent calcium-channels and modulates inositol phospholipid hydrolysis (PubMed:
10075644). Calcium is required for high affinity binding to GABA (By similarity). Plays a critical role in the fine- tuning of inhibitory synaptic transmission (PubMed:
9844003). Pre- synaptic GABA receptor inhibits neurotransmitter release by down- regulating high-voltage activated calcium channels, whereas postsynaptic GABA receptor decreases neuronal excitability by activating a prominent inwardly rectifying potassium (Kir) conductance that underlies the late inhibitory postsynaptic potentials (PubMed:
9844003, PubMed:
9872316, PubMed:
10075644, PubMed:
9872744, PubMed:
22660477). Not only implicated in synaptic inhibition but also in hippocampal long-term potentiation, slow wave sleep, muscle relaxation and antinociception (Probable). Activated by (-)-baclofen, cgp27492 and blocked by phaclofen (PubMed:
9844003, PubMed:
9872316, PubMed:
24305054).
