GABA(C) RECEPTORS

gamma-Aminobutyric acid (GABA) is an important neurotransmitter that mediates inhibition in the vertebrate CNS. Until recently, two receptor subtypes were known: bicuculline-sensitive GABA(A) and baclofen-sensitive GABA(B) receptors. Several lines of evidence now indicate the existence of a third class of GABA receptor, which is distinct pharmacologically from GABA(A) and GABA(B) receptors and is found predominantly in the vertebrate retina. These novel GABA(C) receptors are CI- pores. They are insensitive to drugs that modulate GABA(A) and GABA(B) receptors and are activated selectively by cis-4-aminocrotonic acid.