Objective: To study the effect of open calcium channel and adrenoceptor stimulation on La3+ transmembrane behavior of guinea pig ventricular myocytes.Methods: The change of 340/380nm fluorescence intensity ratio was detected by Fura-2 fluorescence probe technique to determine La3+ transmembrane behavior.Results: Although the voltage-dependent calcium channel(VDCC) was opened by calcium channel agonist Bay K8644 and KCl(35mmol/L) depolarization,La3+ could not enter into guinea pig ventricular myocytes under ...