DDPH对豚鼠心室乳头状肌细胞电压与频率依赖性的电生理作用

目的　观察１ （２，６ 二甲基苯氧基） ２ （３，４ 二甲氧基苯乙氨基） 丙烷盐酸盐〔１ （２，６ ｄｉｍｅｔｈｙｌｐｈｅｎｏｘｙ） ２ （３ ，４ ｄｉｍｅｔｈｏｘｙｐｈｅｎｙｌｅｔｈｙｌａｍｉｎｏ） ｐｒｏｐａｎｅ ｈｙｄｒｏｃｈｌｏｒｉｄｅ， ＤＤＰＨ〕对豚鼠右心室乳头状肌细胞电压与频率依赖性的电生理作用。方法　采用常规细胞内玻璃微电极技术，分别以０－０２Ｈｚ、２ Ｈｚ 的刺激频率，观察ＤＤＰＨ（１ ～５０ μｍｏｌ·Ｌ－１） 对豚鼠右心室乳头状肌细胞动作电位（ＡＰ） 各参数的影响，并采用０－１ ～３－３ Ｈｚ 的刺激频率和提高Ｋ＋ 浓度（２－７ ～１５ ｍｍｏｌ·Ｌ－ １）将静息膜电位除极化到不同的水平，观察了ＤＤＰＨ（１０μｍｏｌ·Ｌ－１）对豚鼠右心室乳头状肌细胞动作电位零相最大除极化速率（ Ｖｍａｘ）频率与电压依赖性的抑制作用。结果　ＤＤＰＨ以浓度依赖降低豚鼠右心室乳头状肌细胞动作电位振幅（ＡＰＡ） 、缩短动作电位复极５０ ％ 时程（ＡＰＤ５０） 、延长动作电位复极９０％ 时程（ＡＰＤ９０） 并抑制Ｖｍａｘ ，但不明显改变静息膜电位（ＲＰ），其作用在刺激频率为２ Ｈｚ 时较０－０２ Ｈｚ 时更为明显。对Ｖｍａｘ 呈现出刺激频率

Voltage and frequency dependent electrophysiological effects of DDPH on isolated guinea pig right ventricular papillary muscle

AIM The study was performed to observe the voltage and frequency dependent electrophysiological effects of 〔1 (2,6 dimethylphenoxy) 2 (3,4 dimethoxyphenylethylamino) propane hydrochloride, DDPH〕 on isolated guinea pig right ventricular papillary muscle. METHODS Effects of DDPH (1～50 μmol·L -1 ) on action potential (AP) of isolated guinea pig right ventricular papillary muscles driven at basal rates of 0 02 Hz and 2 Hz were studied respectively using conventional microelectrode techniques. Frequency and voltage dependent electrophysiological effects of DDPH on the maximal rate of rise of phase 0 ( V max ) of action potential were also studied in guinea pig right ventricular papillary muscles driven by different stimulation frequencies (0 1～3 3 Hz) and the resting membrane potential was depolarized in a stepwise manner by increased the K + concentrations from 2 7 to 5 4,8 1,10 8,13 5 and 15 mmol·L -1 . RESULTS DDPH decreased AP amplitude (APA),shortened AP 50% duration (APD 50 ), decreased V max and prolonged AP 90% duration(APD 90 ) in concentration dependent manner, but there was no significant effect on resting membrane potential(RP). Frequency and voltage dependent V max inhibition was augmented at higher stimulation frequencies and higher resting membrane potential. CONCLUSION DDPH has effect of frequency and voltage dependent V max inhibition on guinea pig right ventricular guinea pig right ventricular papillary muscles.