Fig. 3.

Drug and hormone effects on APD in perfused hearts and isolated cardiomyocytes. A-C. Effects on monophasic APD acquired in Langendorff-perfused hearts at 75% of repolarization (MAPD75) during perfusion with oxytocin (n = 8) (A), fluoxetine and fluoxetine + oxytocin (n = 10) (B), risperidone and risperidone + oxytocin (n = 8) (C) are shown. Exemplary monophasic action potential (AP) recordings are shown in left columns. Indicated are APs at baseline (black lines) and with hormones / drugs (colored lines). Middle column: Dots plots of individual APD₇₅ at baseline and with hormone / drug perfusion. All monophasic APD were investigated at body temperature at a stimulation rate of 2 Hz. D-F. Drug and hormone effects on cellular action potentials recorded in current clamp. Representative examples of the prolonging effect of oxytocin (Oxy) (D), fluoxetine (Fluo) (E), risperidone (Risp) (F) and their combination with Oxy on action potentials recorded from rabbit cardiomyocytes at room temperature at a stimulation rate of 1 Hz. Control drug-free (Bsl) action potentials are indicated in black. Right columns show dots plots of individual APD₉₀ at baseline and with hormone / drug perfusion. Differences are indicated as * p < 0.05; ** p < 0.01; ***p < 0.001.