title: Tetrandrine, a bisbenzylisoquinoline alkaloid from Chinese herb Radix, augmented the hypnotic effect of pentobarbital through serotonergic system.
abstract: 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.
authors.affiliation: Department of Pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Lu, Beijing 100083, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.forename: Xiang-Yu
authors.initials: XY
authors.lastname: Cui
authors.forename: Bao-Qiong
authors.initials: BQ
authors.lastname: Chen
authors.forename: Qing-Ping
authors.initials: QP
authors.lastname: Chu
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Yao
authors.forename: Bao-Shan
authors.initials: BS
authors.lastname: Ku
authors.forename: Yong-He
authors.initials: YH
authors.lastname: Zhang
mesh_terms: 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
chemical_list: D000470:Alkaloids; D044182:Benzylisoquinolines; D006993:Hypnotics and Sedatives; D018490:Serotonin Agents; C009438:tetrandrine; D012701:Serotonin; D010424:Pentobarbital; D003975:Diazepam; D010134:Fenclonine