Abstract: Objective To investigate the effects of adenosine on spontaneous action potentials of left ventricular outflow tract and the effects of adenosine on E, hypoxia and acidosis. Methods By using conventional intracellular microelectrode technique to record action potentials, adenosine was used to study the electrophysiological effects on pacemaker cells in ventricular outflow tract. The effects of adenosine on E, hypoxia and acidosis were also studied. Results ① Adenosine significantly decreased the electric activities of pacemaker cells in guinea pig left ventricular outflow tract. From 10μmol/L adenosine to 100μmol/L adenosine, the effects were more marked. ②10μmol/L E resulted in a significant increase in the autorhythmicity of left ventricular outflow tract. 50μmol/L adenosine decreased the effects of E notably. ③Hypoxia and acidosis led to a marked decrease in the autorhythmicity of left ventricular outflow tract. 50μmol/L adenosine led to a notably decrease in the effects of hypoxia and acidosis. Conclusion Adenosine could significantly decrease the autorhythmicity of left ventricular outflow tract and markedly alter the effects of E, hypoxia and acidosis.