title: Effects of daurisoline on intracellular Ca2+ activity in myocardium.
abstract: OBJECTIVE
  To explain the effect of daurisoline (DS) on delayed afterdepolarization (DAD).
  
  
  METHODS
  Ca(2+)-sensitive microelectrode technic was used to record intracellular Ca2+ activity (alpha Cai) and triggered activity (TA) arising from DAD in myocardium.
  
  
  RESULTS
  Strophantin G 3 mumol.L-1 yielded an increase in resting myocardial alpha Cai by 0.19 +/- 0.11 mumol.L-1 and transient elevations of alpha Cai by 1.48 +/- 0.55 and 4.96 +/- 1.81 mumol.L-1, respectively during the development of DAD and TA. By pretreatment with DS or verapamil, strophantin G-caused elevations of the alpha Cai in resting and provoked myocardia were eliminated and TA disappeared. DS 50 mumol.L-1 reduced Na(+)-free medium-induced elevation of dog Purkinje fibrous alpha Cai and abolished caffeine-induced increase of dog myocardial alpha Cai.
  
  
  CONCLUSIONS
  DS inhibited DAD and TA by preventing an increase of alpha Cai via transmembrane Ca2+ entry and Ca2+ release from the reticulum.
authors.affiliation: Department of Clinical Pharmacology, Tongji Medical University, Wuhan, China.
authors.forename: Z X
authors.initials: ZX
authors.lastname: Wang
authors.forename: J Q
authors.initials: JQ
authors.lastname: Zhu
authors.forename: F D
authors.initials: FD
authors.lastname: Zeng
authors.forename: C J
authors.initials: CJ
authors.lastname: Hu
authors.forename: Y L
authors.initials: YL
authors.lastname: Ma
authors.forename: S M
authors.initials: SM
authors.lastname: Zhong
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D044182:Benzylisoquinolines; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004285:Dogs; D005260:Female; D006168:Guinea Pigs; D008297:Male; D008839:Microelectrodes; D009206:Myocardium / Q000378:metabolism*; D010210:Papillary Muscles / Q000378:metabolism; D011690:Purkinje Fibers / Q000378:metabolism
chemical_list: D000470:Alkaloids; D000889:Anti-Arrhythmia Agents; D044182:Benzylisoquinolines; D002121:Calcium Channel Blockers; C023968:daurisoline; D002118:Calcium