Effect of pizotifen on convulsive effect of meso-tetra-4N-methyl-pirydyl-porphyrin [P] in mice

In this report we present effect of pizotifen, an antagonist of serotonin (5-hydroxytryptamine; 5-HT) receptors, on P-induced convulsions in mice. Experiments were conducted on male mice Balby. Convulsive effect P was determined using the following measures: percentage of mice with seizures, the number of seizure episodes/2 h, the latency time of the beginning P-induced seizure activity in mice and P-induced seizure activity of mice determined by score of Racine. Pretreatment mice with pizotifen (0.5 mg/kg ip) did not prevent convulsive effect P, applied ip at the dose of 50 μmol/kg ip (59.3 mg/kg) but significantly shortened the latency time of the beginning of P-induced seizure activity of mice. We conclude that central serotonin receptors are involved in the mechanism of P-induced convulsions.