Abstract: Objective To investigate the effect and mechanism of sphingosine 1-phoshate (S1P) on action potential (AP) and voltage-dependent potassium current (KV）in isolated guinea pig ventricular myocytes. Methods The ventricular myocytes were isolated by using Langendorff perfusion method. The AP and KV were recorded by whole cell patch-clamp recording technique. Results S1P prolonged the 50% and 90% action potential duration (APD50 and APD90) and decreased KV which were blocked by pertussis toxin (PTX) or Calphostin C. Conclusion S1P decreased the KV in a PKC pathway and prolonged action potential duration in guinea-pig ventricular myocytes.

Key words: Sphingosine 1-phoshate, Ventricular myocytes, Action potential, Voltage-dependent potassium current