双苯氟嗪对异丙肾上腺素所致早后除极和触发活动的影响

Effects of dipfluzine on isoprenaline-induced early afterdepolarizations and triggered activity

用异丙肾上腺素 ( Iso)诱发豚鼠右心室乳头肌产生早后除极 ( EAD)和触发活动 ( TA) ,通过细胞内微电极技术 ,观察双苯氟嗪 ( Dip)对 EAD和TA的预防作用 .在 0 .5Hz刺激频率下 ,50 nmol· L-1Iso在延长动作电位时程的基础上 ,可诱发豚鼠乳头肌产生 EAD,并出现 TA,有时 TA会发展成持久的节律性活动 ,有的还伴有 EAD或迟后除极 . Dip 3和 1 0μmol· L-1可显著降低 Iso诱发的 EAD波幅及发生率和 TA发生率 ;Dip1 0 μmol·L-1还明显延长 TA潜伏期 .结果提示 ,Dip能预防 ,减少或延迟 Iso引起的豚鼠乳头肌 EAD和TA.

The effects of dipfluzine (Dip) on early afterdepolarizations(EADs) and triggered activity(TA) induced by isoprenaline(Iso) were observed with intracellular microelectrode technique in guinea pig papillary muscles. Iso 50 nmol·L -1 induced EADs and TA in guinea pig papillary muscle on the basis of prolonged action potential duration at the stimulation rate of 0.5 Hz. Sometimes, TA developed into sustained rhythmic activity that might be accompanied by EADs or delayed afterdepolarizations. Dip 3 and 10 μmol·L -1 markedly reduced the amplitude of EADs and the incidences of EADs and TA induced by Iso. Dip 10 μmol·L -1 significantly prolonged the latency of TA in addition. It is suggested that Dip attenuate or postpone the occurrence of Iso induced EADs and TA in guinea pig papillary muscles, and thus produce its preventive effect on the occurrence of EADs and TA.