Inhibition by agmatine on spontaneous activity of rabbit atrioventricular node cells

摘要

Agmatine not only reduced the amplitude of action potential(APA), maximal rate of de- polarization(V_max), velocity of diastolic(phase 4)de- plarization(VDD), and rate of spontaneous firing (RSF), but also prolonged 90/100 duration of action po- tential(APD_90)in a concentration-dependent manner. The effects of agmatine(10 mmol/L)could be blocked Completely by pretreatment with idazoxan(0.1 mmol/ L), an imidazoline receptor(IR)and α_2-adrenergic re- Ceptor(α_2-AR)antagonist. The inhibitory effects of agma- Tine on spontaneous activity of AV node cells in rabbits Were likely mediated by IR and/or α_2-AR, and were re- Lated to the reduction in calcium influx and potassium ef- Flux.