title: [Effects of TWP on capacity of muscle contraction].
abstract: OBJECTIVE
  To investigate the direct effects of Tripterygium Wilfordii Polyglycosidium (TWP) on capability of muscle contraction.
  
  
  METHODS
  Using electronic stimulator to stimulate the phrenic nerve of the isolated phrenic nerve diaphragm preparation of 30 rats or directly stimulate the isolated gastrocnemius muscle preparation of 45 toads in vitro, we studied the effects of TWP on capability of muscle intrinsic contraction.
  
  
  RESULTS
  TWP in 20 mg/L increased the amplitude of muscle contraction in initial 60 min but did not make further increase of the amplitude of muscle contraction from 60 min to 90 min in the isolated phrenic nerve diaphragm preparation of rat under one-third optimal stimulus. TWP in 40 mg/L and in 60 mg/L did not cause decrease of amplitude of muscle contraction in initial 60 min in isolated phrenic nerve diaphragm preparation of rat under one-third optimal stimulus. TWP in 60 mg/L did not cause decrease of tension of signal-contraction in initial 30 min in isolated gastrocnemius muscle preparation of toad under one-third optimal direct stimulus. Solvent DMSO could obviously reduce the tension of muscle contraction both in isolated phrenic nerve diaphragm preparation of rat and in isolated gastrocnemius muscle preparation of toad under one-third optimal stimulus.
  
  
  CONCLUSIONS
  TWP can limitedly enhance the capability of muscle contraction; Solvent DMSO can restrain muscle contraction.
authors.affiliation: Department of Physiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jingrui
authors.initials: J
authors.lastname: Yu
authors.forename: Guangneng
authors.initials: G
authors.lastname: Lü
authors.forename: Keyong
authors.initials: K
authors.lastname: Li
authors.forename: Jianguo
authors.initials: J
authors.lastname: Xu
mesh_terms: D000818:Animals; D002023:Bufo bufo; D003964:Diaphragm / Q000502:physiology; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000494:pharmacology; D005260:Female; D006027:Glycosides / Q000494:pharmacology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000502:physiology*; D009469:Neuromuscular Junction / Q000502:physiology; D010791:Phrenic Nerve / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D029757:Tripterygium / Q000737:chemistry*
chemical_list: D004365:Drugs, Chinese Herbal; D006027:Glycosides