Fig. 3

Norepinephrine (NE), β-adrenoreceptors agonist isoproterenole (ISO), α-adrenoreceprors agonist phenylephrine cause periodic bursts (NA, ISO) or permanent (NA, ISO, PHE) spontaneous AP (SAP) in quiescent BALB/c pulmonary vein myocardium. a Representative examples of NE-, ISO- and PHE-induced permanent SAP in collapsed (left) and expanded (right) time scale. b Representative examples of NE- and ISO-induced repetitive bursts in different time scales. c NE and ISO lead to significantly more pronounced hyperpolarization of RMP in PV in comparison to PHE. * p < 0.05 (relative to PHE). D. NE-, ISO- or PHE-induced permanent ectopic automaticity in murine PV is accompanied by resting membrane potential (RMP) hyperpolarization