Effects of chloroquine on pentylenetetrazol-induced convulsions in mice.

The effects of chloroquine pretreatment were investigated on pentylenetetrazol-induced clonic-tonic convulsions in mice. The results demonstrated that lower doses of chloroquine (1.0-5.0 mg kg-1) significantly induced a delay in onset time to the clonic component of convulsions and reduced the incidence of the tonic phase of convulsions and mortality. In contrast, at a higher dose range (10.0-50.0 mg kg-1) chloroquine had opposite effects. This study points out the biphasic action of chloroquine on clonic-tonic PTZ convulsions and its preferential effect against the tonic phase of convulsions.