[Daphnia magna Straus: a test object for the pharmacological evaluation of GABA-ergic drugs in the whole organism].

The toxicity of a series of GABAlytics (11 drugs) representing different pharmacological groups was evaluated in comparative experiments on Daphnia magna Straus and white mice. A high degree of correlation was established between the toxicity of GABA antagonists studied in daphnia and mice. The pharmacological analysis of the interaction of agonists and antagonists of GABA/benzodiazepine/ionophore-receptor complex--the competitive ligands for various binding sites--was carried out. It is suggested that the ability of GABA agonists to prevent the action of GABA antagonists in whole organism is mainly determined by their pharmacokinetic and pharmacodynamic features, rather than by direct competition for binding sites within the receptor complex.