GABA rho 2 receptor pharmacological profile: GABA recognition site similarities to rho 1.

The rho 2 receptor for gamma-aminobutyric acid (GABA) induces GABA-gated currents when expressed as a homooligomer in Xenopus oocytes. rho 2 responses display pharmacological profiles similar to those of expressed rho 1 receptors, although responses were slower, most agonists were more potent at rho 2 and Im values for the partial agonist imidazole-4-acetic acid were 7-fold higher. Amino acids important for most aspects of GABA agonist ligand recognition may not be among those that differ between rho 1 and rho 2, including the 20% amino acid difference in the N-terminal region.