title: Effects of diacetyl guan-fu base A on pacemaker cells in sinoatrial node of rabbits.
abstract: OBJECTIVE
  To study the electrophysiological effects of diacetyl guan-fu base A (DGFA) on pacemaker cells in sinoatrial (SA) node.
  
  
  METHODS
  Intracellular microelectrode method was used to record parameters of action potential (AP) in SA node of rabbits.
  
  
  RESULTS
  DGFA could not only slow down spontaneous firing frequency (SFF), mean rate of repolarization (MRR), and rate of diastolic depolarization (RDD), but also prolong diastolic interval (DI) and duration of action potential (APD) in a concentration-dependent manner in SA node. Furthermore, DGFA markedly decreased the maximum rate of depolarization (MRD) with a slight reduce of the amplitude of action potential (APA) and there was no significant effect on the maximal diastolic potential (MDP). The decrease in SFF caused by DGFA was not affected by atropine (0.05 mg/L).
  
  
  CONCLUSIONS
  The effects might be due to the reduction of calcium influx and potassium efflux, and the muscarinic receptors were not involved.
authors.affiliation: Department of Pharmacology, College of Pharmacy, Shandong University, Jinan 250012, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Sun
authors.forename: Qing-Zhu
authors.initials: QZ
authors.lastname: Zhang
authors.forename: Ru-Bin
authors.initials: RB
authors.lastname: Wang
authors.forename: Jian-Bo
authors.initials: JB
authors.lastname: Ji
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D004594:Electrophysiology; D005260:Female; D008297:Male; D011817:Rabbits; D012849:Sinoatrial Node / Q000166:cytology* / Q000502:physiology
chemical_list: D000470:Alkaloids; C119184:diacetyl guan-fu base A