摘要
目的探讨镉(Cd)对心肌细胞Ca2+通道阻滞作用的机制,比较亚硒酸钠(NaSe)与硒代蛋氨酸(SeMet)两种硒化合物的保护效应。方法在培养的Wistar大鼠心肌细胞上观察B、L、T三型Ca2+通道的单通道电活动。结果Cd浓度为10μmol/L时,心肌细胞B、L型Ca2+通道受到明显阻滞;而对T型Ca2+通道没有影响。在加入Cd的同时,分别加入等浓度的NaSe和SeMet,NaSe能拮抗Cd对B、L型Ca2+通道的阻滞作用,SeMet仅能减轻Cd对L型Ca2+通道的阻滞,而且使T型Ca2+通道的关闭时间延长。结论Cd对心肌细胞B、L型Ca2+通道具有明显的阻滞作用,而对T型Ca2+通道没有影响;两种硒化合物均可影响Cd致心肌细胞膜Ca2+通道的阻滞作用,NaSe的保护作用比SeMet更有效。
Objective To study the effects of cadmium on the
single channel activities of Btype,Ltype and Ttype Ca2+ channels of cultured ventricular
myocytes of neonatal Wistar rats and the protective effects of selenium. Methods Patch clamp
technique was conducted in the study.The opening of L and T type calcium channels were
evoked by a depolarizing test pulse from -50 to +10 mV and from -70 to -10 mV
respectively,while B type calcium channel was recorded at -60 mV without depolarizing test
pulse. Results Cadmium at dose of 10 mol/L significantly inhibited the activities of Btype and
Ltype Ca2+ channels but not on Ttype Ca2+ channel.The open time of Btype and Ltype Ca2+
channels shortened by 33.5% and 40.7% respectively and the openstate probability(Po) of them
decreased by 55.0% and 50.0% respectively,whereas there was no significant variation in the
amplitude of ionic current flowing(Iba) through the Ca2+ channels.When selenium and cadmium
were added in equal molarity(10 mol/L) simultaneously,sodium selenite could antagonize the
inhibition of Cd on B and L type Ca2+ channels,while selenomethionine only attenuated the
inhibition on L type Ca2+ channel. Conclusion Both sodium selenite and selenomethionine had
protective effects on cadmiuminduced inhibition of Ca2+ channels,and sodium selenite was
more effective than selenomethionine.
出处
《中华劳动卫生职业病杂志》
CAS
CSCD
1999年第3期161-163,共3页
Chinese Journal of Industrial Hygiene and Occupational Diseases
基金
国家自然科学基金
关键词
镉
亚硒酸钠
硒代蛋氨酸
心肌细胞
钙通道阻滞
CadmiumSodium
seleniteSelenomethionineMyocardiocyteCalcium channelPatch clamp technique