Tetrandrine, a bisbenzylisoquinoline alkaloid from Chinese herb Radix, augmented the hypnotic effect of pentobarbital through serotonergic system.
This is the first study of hypnotic activity of tetrandrine (a major component of Stephania tetrandrae) in mice by using synergism with pentobarbital as an index for the hypnotic effect. The results showed that tetrandrine potentiated pentobarbital (45 mg/kg, i.p.)-induced hypnosis significantly by reducing sleep latency and increasing sleeping time in a dose-dependent manner, and this effect was potentiated by 5-hydroxytryptophan (5-HTP). In the subhypnotic dosage of pentobarbital (28 mg/kg, i.p.)-treated mice, tetrandrine (60 and 30 mg/kg, p.o.) significantly increased the rate of sleep onset and also showed synergic effect with 5-HTP. Pretreatment of p-chlorophenylalanine (PCPA, 300 mg/kg, s.c.), an inhibitor of tryptophan hydroxylase, significantly decreased pentobarbital-induced sleeping time and tetrandrine abolished this effect. From these results, it should be presumed that serotonergic system may be involved in the augmentative effect of tetrandrine on pentobarbital-induced sleep.
Zhao
Xin
X
Department of Pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Lu, Beijing 100083, PR China.
Cui
Xiang-Yu
XY
Chen
Bao-Qiong
BQ
Chu
Qing-Ping
QP
Yao
Hai-Yan
HY
Ku
Bao-Shan
BS
Zhang
Yong-He
YH
D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D044182:Benzylisoquinolines / Q000494:pharmacology*; D003975:Diazepam / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D010134:Fenclonine / Q000494:pharmacology; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010424:Pentobarbital / Q000494:pharmacology*; D012701:Serotonin / Q000502:physiology*; D018490:Serotonin Agents / Q000494:pharmacology; D012890:Sleep / Q000187:drug effects
D000470:Alkaloids; D044182:Benzylisoquinolines; D006993:Hypnotics and Sedatives; D018490:Serotonin Agents; C009438:tetrandrine; D012701:Serotonin; D010424:Pentobarbital; D003975:Diazepam; D010134:Fenclonine