AIM: To study the effect of adrenomedullin (ADM) on L-type calcium currents (I Ca,L) and its signaling transduction process in guinea-pig ventricular myocytes. METHODS: By using whole-cell patch clamp technique, the effect of ADM(1-100 nmol?L -1) on I Ca,Lmyocyte. Furthermore, the possible signaling transduction process of ADM on I Ca,L was investigated by observing the effects of ADM 22-52 (a specific ADM-receptor antagonist,100 nmol?L -1)+ADM(100 nmol?L -1), H-89 (a specific protein kinase A inhibitor, 10 ?mol?L -1) + ADM(100 nmol?L -1), PKC 19-36 (a specific protein kinase C inhibitor, 10 ?mol?L -1) + ADM(100 nmol?L -1) and PMA (a specific protein kinase C activator, 1 ?mol?L -1) on I Ca,L, respectively. RESULTS: ADM at the concentrations of 1-100 nmol?L -1 decreased I Ca,L in a dose-dependent manner (P

AIM:To determine the role of Kv1 2, Kv1 5, Kv2 1 in the hypoxia pulmonary vasoconstriction (HPV). METHODS: Male Wistar rats were divided into two groups: normoxic group and hypoxic group. The single smooth muscle cell was obtained from pulmonary artery of Wistar rats with acute enzymatic digestion method. The conventional whole-cell patch clamp technique was used to record the resting membrane potential (Em) and the potassium currents of voltage-gated potassium channel (IKv) in rat pulmonary arterial smooth muscle cells (PASMC). Intracellular application of Kv1 2/Kv1 5/Kv2 1 antibodies (1∶125) was conducted through the whole-cell patch clamp system. RESULTS: ① Em of PASMC was depolarized after 24 h hypoxia compared with that of control cells [from (-51 8?0 8) mV to (-47 2? 0 7) mV, P