Identification of GABA receptor genes and evidence of GABA signaling during embryogenesis of the sea urchin

Gamma-aminobutyric acid (GABA) is the principal inhibitory neurotransmitter in the mammalian central nervous system and acts via ionotropic (GABAA-Rs) and metabotropic (GABAB-Rs) receptors. GABAA-Rs are Cl- selective hetero-pentameric channels assembled by combinations of 19 distinct gene products. Instead, GABAB-Rs are bi-subunit G-protein coupled receptors linked to K+ or Ca2+ channels. Dysfunctions of GABA-signaling (GS) cause psychotic disorders and correlate with epigenetic alterations, such as over-expression of DNA methyl transferase-1 which in turn imposes iper-methylation of GABA-regulated genes. The sea urchin embryo, which presents a rudimentary nervous system, offers a big oppor…