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摘 要:
应用细胞内微电极技术,
观察了genistein
(GST)对豚鼠乳头肌的电生理效应。结果显示:
(1) GST (10～100
μmol/L)浓度依赖地缩短正常乳头肌动作电位时程;
(2)对部分去极化乳头肌,
GST (50 μmol/L)除缩短动作电位时程外,
还使动作电位幅值和超射值降低,
零相最大上升速度减慢;
(3)预先应用一氧化氮合酶抑制剂LNNA
(5 mmol/L), 不影响GST
(50 μmol/L)的电生理效应;
(4)单独应用17β雌二醇(E2,
5 μmol/L)或GST
(10 μmol/L)时,
动作电位各参数无明显变化,
而预先应用同剂量的GST再加入E2,
则动作电位时程缩短。结果提示,
GST可能通过非NO途径抑制Ca2+内流,
从而影响豚鼠乳头肌电生理效应,
并与E2有加强或协同效应。
关键词:
植物性雌激素;
genistein; 乳头肌;
电生理;
17β雌二醇
学科分类号:
Q463
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Electrophysiological effects of phytoestrogen genistein on guinea pig
papillary muscles
MA Tao, FAN ZhenZhong,
HE RuiRong*
(Department of Physiology, Institute of Basic Medicine, Hebei Medical
University, Shijiazhuang 050017)
Abstract:
The cardiac electrophysiological effects of genistein (GST)were examined
in guinea pig papillary muscle using intracellular microelectrode
technique. The results obtained are as follows. (1) Duration of action
potential (APD) in normal papillary muscles was decreased by GST (10～100
μmol/L)
in a concentrationdependent
manner. (2) In partially depolarized papillary muscles, 50
μmol/L
GST not only reduced APD, but also decreased the amplitute of action
potential, overshoot and maximal velocity of phase 0 depolarization. (3)
Pretreatment with NωnitroLarginine
(LNNA,
5 mmol/L) failed to affect the above effects of GST (50
μmol/L)on
papillary muscles. (4) 17βestradiol
(E2, 5 μmol/L)
or GST (10 μmol/L)
alone did not affect action potential, while GST combined with E2 at the
same doses shortened APD significantly. All these results indicate that
the effects of GST on papillary muscles are likely due to a decrease of
calcium inflow which is not mediated by NO and that GST have facilitative
or synergetic action with E2.
Key words:
phytoestrogen; genistein; papillary muscles; electrophysiology; 17βestradiol
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