ZK-93423 is an anxiolytic drug from the ò-carboline family, closely related to abecarnil. It is a nonbenzodiazepine GABA<sub>A</sub> agonist which is not subtype selective and stimulates ñ<sub>1</sub>, ñ<sub>2</sub>, ñ<sub>3</sub>, and ñ<sub>5</sub>-subunit containing GABA<sub>A</sub> receptors equally. It has anticonvulsant, muscle relaxant and appetite stimulating properties comparable to benzodiazepine drugs. ZK-93423 has also been used as a base to develop new and improved beta-carboline derivatives and help map the binding site of the GABA<sub>A</sub> receptor.