Objective: To study NOS activities in serum of rats under different stresses. Methods: Two models of stress were made in rats, one is the conventional forced swimming model (including 12 rats), and the other is a social defeated paradigm (including 12 rats). The activities of NOS of rats under each model and of one control group (10 rats) were measured. Results: Compared with control, the NOS activity under social defeated paradigm was lower (15.36?1.74/17.11?1.67 U/ml, t=2.32, P

Objective: To study the change of NO (nitric oxide) and NOS (nitric oxide synthase) in brain of rats induced by acute stress Method: The concentration of NO and NOS in frontal lob, hippcampus, midbrain and hypothalamus were measured in 1 and 3 hours after stress respectively Results: The concentration of NO and NOS in hippcampus and hypothalamus were significantly higher than that of control group at 1 hour after stress (P