Abstract

Insulin, an important regulator of peripheral metabolism, has been reported to interact with many neurotransmitter systems including those associated with convulsion. The effect of insulin against pentylenetetrazole and strychnine-induced convulsions in mice, as well as possible sex differences, were evaluated in this study. Mice of both sexes weighing between 20 and 25 g were administered insulin intraperitoneally at doses of 1, 2, 4 and 8 IU/kg. Each mouse received a convulsive dose of pentylenetetrazole (100 mg/kg, i.p.) or strychnine (2 mg/kg, i.p.) and was observed for the onset of convulsions and occurrence of death. Against pentylenetetrazole-induced convulsions, all the doses of insulin used significantly (p < 0.05) prolonged the onset of convulsions and significantly delayed the time of death in male mice when compared with control. However, in female mice, only insulin 8 IU/kg significantly prolonged the onset of convulsions, while insulin 4 IU/kg significantly delayed the time of death. Against strychnine-induced convulsions, insulin at the doses of 2 and 4 IU/kg significantly (p < 0.05) prolonged the onset of convulsions in male mice relative to control, while 8 IU/kg insulin significantly prolonged the time of death in male mice compared to control. However, none of the doses of insulin administered to female mice were effective against strychnine-induced convulsions. These results show that insulin produced sex-related protective effects against chemically-induced convulsions in mice.

Keywords: Insulin, convulsion, pentylenetetrazole, strychnine, male mice, female mice.