The Sinomenine The Anxiolytic Effects

The anxiolytic-like effects of sinomenine were investigated by means of behavioral pharmacology for the first time. The other central-acting properties of sinomenine were also examined to see whether clear differences could be observed between it and diazepam.After acute administration, sinomenine (20 , 40 mg/kg) significantly increased the percentage of open arm entries in the elevated plus-maze test. Sinomenine (20, 40 mg/kg) prolonged the time spent in light area without altering the locomotor activity of the animals in the light/dark transition test. Sinomenine (20,40 mg/kg) significantly inhibited stress-induced hyperthermia. In the mouse defense test battery, sinomenine (80 mg/kg) decreased line crossing and rearing significantly in the pretest. In the rat avoidance test, sinomenine decreased avoidance diatance dose-dependently. Sinomenine (40,80 mg/kg) decreased the number of avoidance. In the chase test, sinomenine (80 mg/kg) decreased flight speedsignificantly, sinomenine (40, 80 mg/kg) inhibited the "stops" dose-dependently. In the forced contact test, sinomenine (40,80 mg/kg) decreased upright posture and jump significantly. Sinomenine (80 mg/kg) prolonged the immobility time significantly. In the contextual test, sinomenine decreased jump but failed significantly. In the isolation-induced aggression test, sinomenine (40 _s 80mg/kg) reduced the total fighting time between isolation mouse and intruder mouse. Sinomenine (7 mg/kg) in the LU (low light, unfamiliar) test condition and sinomenine (7,14 mg/kg) in the HU (high light, unfamiliar) test condition all significantly increased social interaction time of pairs of rats. In general, the results seen above indicate that sinomenine, at specific doses, possesses a wide range of anxiolytic properties in different anxiety models.The results of this study suggested that at doses eliciting the anxiolytic effect, sinomenine produce neither influence on amobarbital sodium-induced sleeping and motor activity, nor disrupting learning and memory. But at high dose, sinomenine (180 mg/kg) prolonged amobarbital sodium-induced sleeping time, sinomenien decreased traction time in traction test, decreased the degree of inclined plane test which showed that sinomenine might inhibit the central system and impair muscle tone. In the spontaneous motor activity test, sinomenine (80,...