[The neuromediator mechanisms of the action of korazol].
Present paper analyses the known neurotropic effects of GABA-lytic agent corazole (pentylentetrazole), including both "traditional" anxiogenic convulsant properties at systemic doses > 10 mg/kg and reported recently its anxiolytic effects in doses < 2 mg/kg. Understanding the relations between anxiogenic and convulsant properties of a drug, we studied possible effects of pre-treatment by "anxiolytic" dose of corazole (1 mg/kg i.p.) on corazole-induced convulsions at systemic dose of 90 mg/kg in mice. Despite the expectations, small dose of corazole (1 mg/kg) did not reduce convulsions but rather increased them. This result challenges the hypothesis of possible GABA-ergic mechanisms of "positive" effects of corazole in small doses. The potentiation effects were particularly marked for Straube symptom. The symptom is believed to reflect the excitation of inhibitory spinal motoneurons responsible for tail muscles tonus. Perhaps, corazole at a systemic dose of 1 mg/kg can influence separately on the GABA-receptors located in spinal motoneurons or cells of origin of supruspinal pathways. Other possible neuromediator (including glycine-, glytamat-, opioid-, choline- and monoaminergic) mechanisms for corazole action are discussed to illustrate the mosaic of its neurotropic properties.