L-型钙通道阻滞剂对心肌细胞钙稳态的影响

目的观察L-型钙通道阻滞对心肌细胞的影响。方法取SD大鼠颈部脱臼处死后浸入75%乙醇数秒,迅速开胸摘取心脏,置入盛有37℃预热的台氏液100ml的培养皿中。在超净工作台上用台式液清洗并修剪掉结缔组织,迅速行主动脉插管。将心脏悬挂于Langendroff灌流装置上,剪下心室并剪成约1mm3的组织块,放入37℃预热的含0.2mmol/L Ca2＋台氏液20ml的培养皿中,将心室在溶液中轻轻晃动以分散已解离的心室肌细胞。新分离的细胞在常温下放置1～2h后,用加样器取带少许细胞的原液放入试管中,加入指示剂,给予正常细胞外液灌流,测全细胞胞内钙瞬变作为前对照组;给予硝苯地平溶液灌流,测全细胞胞内钙瞬变作为实验组;给予正常细胞外液灌流,测全细胞胞内钙瞬变作为后对照组。结果不同浓度的硝苯地平对静息状态下心室肌细胞胞内钙信号的影响都不明显,仅10μmol/L硝苯地平可能使静息状态下心室肌细胞胞内钙水平轻微降低,更高浓度的硝苯地平的效果反而减弱。不同浓度的硝苯地平都能不同程度降低心室肌细胞胞内钙瞬变的峰值（P〈0.05）,5μmol/L硝苯地平的标准化值最低,降低心室肌细胞胞内钙瞬变峰值的效果比2μmol/L硝苯地平明显（P〈0.05）。但是10μmol/L硝苯地平、50μmol/L的硝苯地平的降低心室肌细胞胞内钙瞬变峰值的效果反而减弱。结论硝苯地平可以抑制大鼠心室肌细胞的电流。但是,硝苯地平对于静息状态下的心室肌细胞胞内钙信号的影响不明显,可能与硝苯地平只对去极化过程的ICa2＋、Ito和IK有抑制作用有关。

The effect of L-type calcium channel blockers on calcium steady-state of myocardial cell

Objective To observe the effect of L-type calcium channel blockers on calcium steady-state of myocardial cell.Methods SD rats were killed by cervical dislocation after a few seconds,immersion in 75% ethanol,the rapid removal of the heart chest,filled with 37 ℃ into preheated tyrode′s solution 100ml of the culture dish.Cleaned the table in the desktop solution with a clean and trimmed of connective tissue,rapid aortic cannulation.Will be hung on the Langendroff cardiac perfusion device,ventricular and cut about 1mm3 cut into tissue blocks of pre-heated at 37 ℃ with 0.2mmol/L Ca2＋ tyrode′s solution 20ml of the culture dish,Ventricular gently shaking in the solution had been to spread the dissociation of ventricular muscle cells.Freshly isolated cells placed at room temperature 1～2h,the use of pipette to take a few cells with a liquid in a test tube,add indicator,gave the normal extracellular fluid perfusion,the measured whole-cell intracellular calcium transients in control as before group;Gave nifedipine perfusion solution,the measured whole-cell intracellular calcium transients as the experimental group;Gave normal extracellular fluid perfusion,the measured whole-cell intracellular calcium transient as after the control group.Results Different concentrations of nifedipine on resting intracellular calcium in ventricular myocytes of the impact of the signal was not obvious,only 10μmol/L nifedipine may cause ventricular resting intracellular calcium levels decreased slightly,but higher concentrations nifedipine cound reduce the effect.Different concentrations of nifedipine cound reduce the ventricular muscle cells of different levels of intracellular calcium transient peak（P0.05） ,5μmol/L nifedipine,the standardized value of the minimum,reduced ventricular peak intracellular calcium transients more effective than 2μmol/L nifedipine was significantly（P0.05） .However,10μmol/L nifedipine,50μmol/L nifedipine reduced ventricular peak intracellular calcium transients but reduced the effect.Conclusion Nifedipine can inhibit the current in rat ventricular myocytes.However,nifedipine for ventricular resting intracellular calcium signaling in muscle cells has no significant effect,nifedipine may be related only to the polarization of ICa2＋、Ito and inhibiting effect of IK.