Overexpression of cerebral iNOS by MCAO in rats (n = 8 in each group of different treatments). *The numbers of iNOS-positive cells (B) 4 days after MCAO injury was significantly (P < 0.05) increased for MCAO-injured animals treated with an i.v. dose of normal saline (1 mL/kg) compared with MCAO sham controls. †The increased numbers of iNOS-positive cells 4 days after MCAO-injury was significantly decreased for MCAO-injured animals treated with an i.v. dose of agmatine (100 mg/kg) compared with vehicle controls. The photomicrograph (A) illustrates a typical example for a sham-operated control, a vehicle-treated MCAO rat, and an agmatine-treated MCAO rat.