A, Time course for protection by 5α,3α-A and ent-5α,3α-A at doses of 100 and 30 mg/kg respectively in the 6-Hz (32 mA, 3 s) seizure test. The interval between the steroid injection and the electrical stimulus is plotted on the abscissa and the percentage of animals protected against seizures is plotted on the ordinate. B, Time course for protection by 5β,3α-A at a doses of 150, 125, 100 mg/kg and ent-5β,3α-A at a dose of 30 mg/kg in the 6-Hz test. Each point represents at least eight mice. Curves are arbitrary fits to the data; the curve representing 5β,3α-A is to the 100 mg/kg group.