GABA superfamily

The receptors for acetylcholine, GABA, glycine and serotonin have a homologous structure and form a superfamily. The best-investigated representative of this superfamUy is the nicotinic acetylcholine receptor, for which extensive biochemical and structural data are available. The nicotinic acetylcholine receptor can be treated as a representative of the other receptors of the superfamUy since it can be assumed that the structure-function principles of this receptor apply to the others. 

The insect GABA receptor-chloride ionophore complex is found in the CNS and also at peripheral neuromuscular sites. GABA receptors belong to a superfamily of ligand-gated ion channels known as Cys-loop receptors that include nicotinic acetylcholine receptors and glutamate-gated chloride channels (Lester, 2004). Cys-loop receptors are so named because... 

Barnard EA, Darlison MG, Seeburg P (1987) Molecular biology of the GABA receptor the receptor/channel superfamily. TINS, 10, 502. 

These characteristics are shared with subunits that form other ion channels/receptors and thus define a receptor superfamily, usually referred to as the nicotinic family. All members in this superfamily function as either cation- or anion-selective channels, thereby mediating fast excitatory or inhibitory synaptic transmission. In mammalian cells, the cation-selective members include nicotinic and 5HTg receptors, whereas the anion-selective members include GABA, GAB Ac, and glycine receptors. Anion-selective channels in this family are also found in invertebrates these channels are gated by glutamate, 5-HT, histidine, and acetylcholine (1). 

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