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. Author manuscript; available in PMC: 2010 Jul 1.
Published in final edited form as: Epilepsy Res. 2009 Apr 29;85(1):1–30. doi: 10.1016/j.eplepsyres.2009.02.017

Fig. 4. Neurosteroid withdrawal-induced spontaneous seizures in female epilepsy rats.

Fig. 4

The protocol for the catamenial model is illustrated in the top panel. Chronic epilepsy with spontaneous recurrent seizures was induced in rats by pilocarpine treatment. Pilocarpine-induced status epilepticus was terminated after 2 h with diazepam (5 mg/kg, ip) injections and animals with frequent spontaneous seizures (average 2 seizures daily) after 5 months post pilocarpine were utilized for neurosteroid withdrawal cycles. To simulate the hormonal state of the luteal-phase (high progesterone) and menstruation (withdrawal) in epilepsy rats, pseudopregnancy, which is associated with sustained secretion of progesterone and neurosteroids, was induced by gonadotropin regimen. Neurosteroid withdrawal was induced by treatment with finasteride, a 5α-reductase inhibitor that blocks the synthesis of allopregnanolone. Rats undergoing neurosteroid withdrawal exhibited significant (p<0.01) increase in daily seizure frequency as compared to control, non-withdrawing group (bottom panel), which is consistent with perimenstrual type catamenial epilepsy.