title: Effects of dipfluzine on delayed afterdepolarizations and triggered activity induced by ouabain in guinea pig papillary muscles.
abstract: OBJECTIVE
  To investigate the effects of dipfluzine (Dip) on delayed afterdepolarizations (DADs) and triggered activity (TA) induced by ouabain and high Ca2+ in guinea pig papillary muscles.
  
  
  METHODS
  Stable and reproducible DADs and TA in guinea pig papillary muscles were induced by ouabain (1 micromol/L) and high Ca2+ (5.4 mmol/L). DADs and TA were recorded using intracellular glass microelectrode technique.
  
  
  RESULTS
  (1) DADs and TA were markedly inhibited by pretreatment with Dip (10, 30 micromol/L). The amplitude and duration of DADs were reduced by Dip (30 micromol/L) from 10.5 mV +/- 2.2 mV and 230 ms +/- 19 ms to 3.6 mV +/- 0.3 mV and 152 ms +/- 14 ms, respectively, and the induced time of DADs was prolonged from (21+/-5) to (66+/-11) min. TA was not observed. (2) Dip (10, 30 micromol/L) had significant therapeutic effects on DADs and TA. The amplitude and duration of DADs were reduced by Dip (30 micromol/L) from 10.4 mV +/- 1.2 mV and 218 ms +/- 22 ms to 3.3 mV +/- 0.6 mV and 159 ms+/-26 ms. The occurrence of TA was also abolished.
  
  
  CONCLUSIONS
  Dip has inhibitory effects on DADs and TA induced by ouabain and high Ca2+ in guinea pig papillary muscles, which might be related to alleviation of intracellular calcium overload through inhibiting calcium channel and/or calcium release from sarcoplasmic reticulum. The effects of Dip on DADs and TA might produce anti-arrhythmic effects.
authors.affiliation: Department of Pharmacology, Hebei Medical University, Shijiazhuang 050017, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Wang
authors.forename: Yong-Jian
authors.initials: YJ
authors.lastname: Zhang
authors.forename: Yong-Li
authors.initials: YL
authors.lastname: Want
mesh_terms: D000818:Animals; D002118:Calcium; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002936:Cinnarizine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004347:Drug Interactions; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008839:Microelectrodes; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology*; D010210:Papillary Muscles / Q000187:drug effects* / Q000502:physiology
chemical_list: D002121:Calcium Channel Blockers; D009467:Neuromuscular Depolarizing Agents; D002936:Cinnarizine; D010042:Ouabain; C065758:dipfluzine; D002118:Calcium