Surprisingly, a regular dose of pilocarpine (275 mg/kg, s.c.)for the establishment of a chronic epilepsy model in WT mice resulted in 100% mortality in Nos1−/− mice within 1 h due to severe convulsion attacks, indicating abnormal acute hypersensitive reaction of Nos1−/− mice to pilocarpine treatment. This evidence concerns the gene NOS1 and epilepsy.