Effect of medroxyprogesterone on development of pentylenetetrazole-induced kindling in mice.

In the present study, the effect of medroxyprogesterone (MPA) is evaluated for its effect on pentylenetetrazole (PTZ) kindling model of epileptogenesis in mice followed by evaluation on kindling-induced changes in cognitive and motor functions. To explore whether the effects are mediated via progesterone receptors, a selective antagonist of progesterone (mifepristone, MIF) was also taken. Kindling was induced by once every 2 days treatment with PTZ (25 mg/kg, i.p.) for 5 weeks. The seizure severity during induction of kindling and % incidence of animals kindled at the end of 5 weeks were recorded. The motor function was assessed using a grip strength meter, whereas spatial memory was assessed in a cross maze. MPA (5 and 10 mg/kg, i.p.) significantly reduced the seizure severity scores and produced a significant decrease in the incidence of animals kindled at the end of 5 weeks (P<0.01). A higher efficacy was observed against male mice as compared with females following MPA. MIF neither reduced nor delayed the development of PTZ-induced kindling in mice. Also, it couldn't reverse the antiepileptogenic effects of MPA. On grip strength test (GST) and spontaneous alternation behavior (SAB), a significant decline in GST and % alternation was observed in kindled mice which was reversed by pre-treatment with MPA. MIF, however, could reverse only the reduced % alternation and not grip strength (GS) in PTZ-kindled animals. The study shows that MPA has antiepileptogenic effects against development of PTZ-induced kindling in mice that may not be mediated via progesterone receptors.