GABAB receptor

GABABRs stimulate the opening of K+ channels, specifically GIRKs, which brings the neuron closer to the equilibrium potential of K+. This reduces the frequency of action potentials which reduces neurotransmitter release. Thus GABAB receptors are usually considered as inhibitory receptors. GABAB receptors can also function as an excitatory receptor and facilitate neurotransmitter release via increasing the activity of CaV2.3 channels. GABAB receptors usually reduces the activity of adenylyl cyclase and Ca2+ channels by using G-proteins with Gi/G0 α subunits. GABAB receptors are involved in behavioral actions of ethanol, gamma-hydroxybutyric acid (GHB), and possibly in pain. Recent research suggests that these receptors may play an important developmental role. == Structure ==

GABAB receptors are similar in structure to and in the same receptor family with metabotropic glutamate receptors. There are two subunits of the receptor, GABAB1 and GABAB2, and these appear to assemble as obligate heterodimers in neuronal membranes by linking up by their intracellular C termini. This might potentially offer more complexity in terms of the function due to different composition of the receptor. ==Ligands==

Agonists • GABA • Baclofen is a GABA analogue which acts as a selective agonist of GABAB receptors, and is used as a muscle relaxant. However, it can aggravate absence seizures, and so is not used in epilepsy. • gamma-Hydroxybutyrate (GHB) • Phenibut • 4-Fluorophenibut • Isovaline • 3-Aminopropylphosphinic acid • Lesogaberan • SKF-97541: 3-Aminopropyl(methyl)phosphinic acid, 10× more potent than baclofen as GABAB agonist, but also GABAA-ρ antagonist • Taurine • CGP-44532 Positive allosteric modulators • ASP-8062 • CGP-7930 • BHFF • Fendiline • BHF-177 • BSPP • GS-39783 • INDV-1000 Antagonists • Homotaurine • Ginsenosides • 2-Hydroxysaclofen • Saclofen • Phaclofen • SCH-50911 • 2-Phenethylamine • CGP-35348 • CGP-52432: 3-([(3,4-Dichlorophenyl)methyl]amino]propyl) diethoxymethyl)phosphinic acid, CAS# 139667-74-6 • CGP-55845: (2S)-3-([(1S)-1-(3,4-Dichlorophenyl)ethyl]amino-2-hydroxypropyl)(phenylmethyl)phosphinic acid, CAS# 149184-22-5 • SGS-742 == See also ==