Inhibition of myocardial inward rectifier potassium current by propylbutyldopamine

AIM: To study the effects of propylbutyldopamine (PBDA) on the inward rectifier potassium current (Ik1). METHODS: The quasi-steady state current-voltage relationship from the isolated guinea pig ventricular cells were measured using whole-cell patch-clamp techniques with a slow ramp depolarization (8 mV.s-1). RESULTS: PBDA 5, 50, and 100 mumol.L-1 concentration-dependently reduced the inward rectifier potassium current. PBDA blocked Ik1 in guinea pig ventricular cells. The effect of PBDA was not blocked by the selective dopamine D2-receptor blocker, domperidone. CONCLUSION: PBDA inhibited Ik1 directly, independent of the dopamine D2-receptor.