title: [Calcium antagonistic effect of Xanthotoxol on isolated guinea pig atria].
abstract: OBJECTIVE
  To study the mechanism of depressant effect of xanthotoxol (XT) on contractility in the isolated guinea pig atria.
  
  
  METHODS
  The contractile force of the isolated left atria was determined by tension recording method.
  
  
  RESULTS
  In the experiments on contractility of the left atria XT and Verapamil (Ver) significantly depressed the positive staircase phenomena, which was reversed by Ver but not by XT. However, the post-rest potentiation of myocardial contraction in the left atria was only markedly decreased by XT but not by Ver. Furthermore, XT not only attenuated the positive inotropic action, but also delayed the following toxicity response induced by ouabain in the isolated left atria.
  
  
  CONCLUSIONS
  XT blocked not only the voltage dependent calcium channel, but also the receptor operated calcium channel in the isolated guinea pig atria.
authors.affiliation: Department of Pharmacology, Gannan Medical College, Ganzhou 341000.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Liu
authors.forename: Qishen
authors.initials: Q
authors.lastname: Lian
authors.forename: Li
authors.initials: L
authors.lastname: Zhou
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhou
authors.forename: Wei
authors.initials: W
authors.lastname: He
authors.forename: Zunping
authors.initials: Z
authors.lastname: Zhu
authors.forename: Fei
authors.initials: F
authors.lastname: Lai
mesh_terms: D000818:Animals; D019661:Apiaceae / Q000737:chemistry*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004365:Drugs, Chinese Herbal / Q000494:pharmacology; D005260:Female; D011564:Furocoumarins / Q000494:pharmacology*; D006168:Guinea Pigs; D006325:Heart Atria / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D010946:Plants, Medicinal / Q000737:chemistry*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D004365:Drugs, Chinese Herbal; D011564:Furocoumarins; C021768:xanthotoxol; D014700:Verapamil