Results : part 1 effect of iron on contraction in rat endothelium-denuded aortic rings ( 1 ) ferric ammonium citrate ( fac ) ( looumol / l ) caused a phasic response with an initial transient contraction followed by relaxation in thoracic aortic ring (l)100pmol几拘磅酸铁(ferricammoniumcitrate,fac)对血管具有直按收缩效应,可引起大鼠主动脉环发生相位性收缩。