title: Effects of toquipidine on ionic channels of cultured embryonic Xenopus laevis myoblasts and neurons.
abstract: OBJECTIVE
  To study the effects of toquipidine (1-p-methyl-phenyl-2-(alpha-piperidinoacetyl)-1, 2, 3, 4-tetrahydroisoquinoline hydrochloride, Toq), a new anti-arrhythmic agent first synthesized in China, on ionic channels.
  
  
  METHODS
  Ionic channel currents were recorded by whole-cell patch clamp technique in cultured embryonic Xenopus laevis myoblasts and neurons.
  
  
  RESULTS
  Toq (0.1, 1, 10, and 100 mumol L-1) caused a concentration-dependent inhibition of the Na+ currents with IC50 7.2 mumol L-1 (5.3-9.8 mumol L-1). Toq (10 mumol L-1) also suppressed the high-voltage-activated Ca2+ currents in neurons. But the steady-state outward K+ currents in myoblasts were activated by Toq (10 mumol L-1).
  
  
  CONCLUSIONS
  Toq blocked the Na+ and Ca2+ channels and opened the steady-state outward K+ channels.
authors.affiliation: Department of Pharmacology, Shanghai Medical University, China.
authors.forename: P
authors.initials: P
authors.lastname: Zheng
authors.forename: G
authors.initials: G
authors.lastname: Chen
authors.forename: N C
authors.initials: NC
authors.lastname: Shi
authors.forename: S P
authors.initials: SP
authors.lastname: Zhou
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Lu
authors.forename: M H
authors.initials: MH
authors.lastname: Yao
authors.forename: Z Y
authors.initials: ZY
authors.lastname: He
mesh_terms: D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004625:Embryo, Nonmammalian; D007473:Ion Channels / Q000187:drug effects*; D007546:Isoquinolines / Q000494:pharmacology*; D009132:Muscles / Q000166:cytology; D009474:Neurons; D010880:Piperidines / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects; D015222:Sodium Channels / Q000187:drug effects; D044005:Tetrahydroisoquinolines; D014982:Xenopus laevis
chemical_list: D000889:Anti-Arrhythmia Agents; D015220:Calcium Channels; D007473:Ion Channels; D007546:Isoquinolines; D010880:Piperidines; D015221:Potassium Channels; D015222:Sodium Channels; D044005:Tetrahydroisoquinolines; C073853:toquipidine