title: [The effect of LPC on the pacemaker current I(f) in ischemic myocardium and the influence of ISO on it].
abstract: OBJECTIVE
  To observe the effect of LPC on the pacemaker current I(f) in ischemic myocardium and if the effect could be reversed by ISO.
  
  
  METHODS
  By using two microelectrode voltage clamp technique to measure and compare the amplitude of I(f) of ischemic myocardium in the presence of LPC and LPC add ISO.
  
  
  RESULTS
  Ischemia decreased the amplitude of I(f) at all membrane potential levels. Adding LPC 2 x 10(-5) mol/L to the ischemia-like solution, the amplitude of I(f) decreased further (n = 5, P < 0.05), it means that LPC aggravated the inhibitory effect of "ischemia" on the pacemaker activity. Adding LPC 2 x 10(-5) mol/L and ISO 1 x 10(-6) mol/L together to the ischemia-like solution, the amplitude of I(f) increased significantly at membrane potential -90 mV to - 120 mV (n = 8, P < 0.05) compared with ischemia condition, but still did not reach the levels before ischemia.
  
  
  CONCLUSIONS
  In acute myocardial ischemia condition, toxic metabolite LPC accentuated its inhibitory effect on pacemaker current I(f), a local release and accumulation of catecholamine could not completely reverse their inhibitory effect.
authors.affiliation: Department of Physiology, Shanghai Second Medical University, Shanghai 200025, China.
authors.forename: You-Min
authors.initials: YM
authors.lastname: Hu
authors.forename: Ji-Feng
authors.initials: JF
authors.lastname: Fu
authors.forename: Zhao
authors.initials: Z
authors.lastname: Zhang
authors.forename: You-Qiu
authors.initials: YQ
authors.lastname: Xu
mesh_terms: D000818:Animals; D007545:Isoproterenol / Q000378:metabolism*; D008244:Lysophosphatidylcholines / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects*; D008839:Microelectrodes; D017202:Myocardial Ischemia / Q000378:metabolism / Q000503:physiopathology*; D009206:Myocardium; D018408:Patch-Clamp Techniques; D012756:Sheep
chemical_list: D008244:Lysophosphatidylcholines; D007545:Isoproterenol