Chronic verapamil treatment remodels ICa,L in mouse ventricle.
Chronic verapamil treatment remodels ICa,L in mouse ventricle.
复制标题
长期维拉帕米治疗可重塑小鼠心室中的 ICa,L。
DOI：
10.1152/ajpheart.00793.2006
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Satin,Jonathan
中科院分区：
文献类型：
--
作者：
Schroder,Elizabeth;Magyar,Janos;Burgess,Don;Andres,Douglas;Satin,Jonathan
In this study we tested the hypothesis that ventricular homeostasis of L-type Ca2+current (ICa,L) minimally involves regulation of the main pore-forming α-subunit (CaV1.2) and auxiliary proteins that serve as positive or negative regulators ofICa,L. We treated animals for 24 h with verapamil (Ver, 3.6 mg·kg−1·day−1), isoproterenol (Iso, 30 mg·kg−1·day−1), or Iso + Ver via osmotic minipumps. To test for alterations of Ca2+channel complex components we performed real-time PCR and Western blot analysis on ventricle. In addition, cardiac myocytes (CMs) were dispersed and current was recorded in the whole cell configuration to evaluateICa,L. Surprisingly, 24- to 48-h Ver increased CaV1.2 mRNA and protein andICa,Lcurrent (Ver 11 ± 1pA/pF vs. control 7 ± 0.5pA/pF;P< 0.01).ICa,Lfrom CMs in Ver mice showed no change in whole cell capacitance. To examine the in vivo effects of a physiologically relevant Ca2+channel agonist, we treated mice with Iso. Twenty-four-hour Iso infusion increased heart rate; CaV1.2- and CaVβ2mRNA levels were constant, but the Ca2+channel subunit mRNA Rem was increased twofold. Cells isolated from 24-h Iso hearts showed no change in basalICa,Ldensity and diminished responsiveness to acute 1 μM Iso. To further examine the homeostatic regulation of the Ca2+channel, we treated animals for 24 h with Iso + Ver. The influence of Iso + Ver was similar that of to Iso alone on Ca2+channel mRNAs andICa,L, with the exception that it prevented the increase in Rem seen with Iso treatment. Long-term Ca2+channel blockade induces an increase of CaV1.2 mRNA and protein and significantly increasesICa,L.
