Phencyclidine-like effect of cyclazocine on pentylentetrazol-induced seizures in laboratory animals.

The present work deals with an EEG and behavioural study of the effect of cyclazocine against the convulsions due to pentylentetrazol (PTZ) in mice, rats and rabbits. In rats, cyclazocine, at the high doses (15-25 mg/kg) prevents the tonic motor convulsions and EEG epileptiform "grand mal" seizure induced by PTZ. In rabbits and mice, cyclazocine inhibits the tonic motor convulsions without modifying either the spike-frequency or the duration of the PTZ-induced EEG seizures. Naloxone, even at high doses, was not able to block the anticonvulsive effects of cyclazocine on PTZ-induced convulsions in the rat. The effects of cyclazocine were compared to those of phencyclidine. These results confirm the multiple behavioural effects of cyclazocine and support the idea that both cyclazocine and phencyclidine, may act on the PCP/sigma receptor identified in binding studies.