摘要
目的研究M3受体激动剂胆碱对豚鼠心室肌细胞L型钙通道的影响。方法应用全细胞膜片钳技术记录M3受体激动剂胆碱对豚鼠单个心室肌细胞L型钙通道电流(ICa-L)的影响;采用激光扫描共聚焦技术观察细胞内钙离子的变化。结果应用10 mmol.L-1胆碱使豚鼠心室肌细胞ICa-L密度从(9.02±0.82)pA/pF减少到(5.61±0.55)pA/pF(n=4,P<0.01),5 nmol.L-14-DAMP能够使其恢复至(8.12±0.65)pA/pF(n=4,P<0.01);10 mmol.L-1胆碱抑制KCl除极诱导的心肌细胞内钙的升高,从(2.76±0.05)降至(1.37±0.05)倍(n=8,P<0.01),5 nmol.L-14-DAMP可以阻断该作用(n=8,P<0.01)。结论M3受体激动剂胆碱通过延长L型钙通道激活过程而明显抑制ICa-L,减少细胞外的钙离子内流,降低心肌细胞内钙,从而发挥抗心律失常作用。
Aim To investigate the effects of M3 receptor agonist choline on L-type calcium channels in guinea pig ventricular myocytes. Methods Whole cell patch clamp technique was used to record L-type calcium current. Laser scanning confocal microscope （LSCM） was employed to measure the concentration of intracellular free calcium. Results The application of 10 mmol·L^-1 choline reduced the density of peak ICa-L from（9. 02±0. 82） pA/pF to（5.61±0. 55）pA/pF（n =4,P 〈0.01）. ICa-L came back to （8. 12±0.65） pA/pF after the application of 5 nmol·L^-1 4-DAMP. Choline remarkably shifted activation curve to the right, and delayed the voltage-dependent steady-state activation of calcium current. The half activation potential （V1/2） was （ - 18.62 ± 1.14 ） mV in the control and （ -21.40 ± 1.12） mV in the presence of choline 10mmol·L^-1（ n = 6, P 〈 0.05 ）. Steady-state inactivation curve and the recovery time from inactivation were not affected markedly. LSCM recorded that KCl induced determined by used [ Ca^2＋ ]i increasing could be depressed by choline （10mmol·L^-1） and the effect of choline could be blocked by 4-DAMP （5 nmol·L^-1）. Conclusion Choline slows the activation procession of ICa-L and decreased [Ca^2＋]; in ventricular myocytes will help its cardiac protection.
出处
《中国药理学通报》
CAS
CSCD
北大核心
2009年第5期573-576,共4页
Chinese Pharmacological Bulletin
基金
国家自然科学基金面上资助项目(No30672644)
关键词
M3受体
胆碱
4-DAMP
钙离子通道
膜片钳技术
激光扫描共聚焦
myocardium M3 receptor
choline
4-DAMP
calcium channel
patch-clamp technique
laser scanning confocal microscope
