钙调素拮抗剂与钙通道阻滞剂对离体大鼠心脏钙反常损伤心肌保护作用的研究

目的:观察钙调素拮抗剂三氟拉嗪(TFP)及钙通道阻滞剂异博定(VP)对缺钙-复钙损伤心肌的保护作用。方法:应用TFP与VP对离体大鼠心脏进行灌流。检测心肌钙含量、灌流液中乳酸脱氢酶(LDH)及心肌蛋白漏出量等指标。结果:TFP显著减少损伤心肌的钙含量、LDH及蛋白漏出量,与对照组相比差异显著(P＜0.01)。VP灌注组与对照组相比各项指标差异无显著(P＞0.05)。TFP与VP联合应用各项检测指标值明显低于单独应用TFP(P＜0.01)。结论:TFP有效减轻钙反常心肌损伤的程度;VP对钙反常心肌无保护作用。联合应用TFP与VP的心肌保护效果更佳。钙反常时Ca²⁺大量内流主要通过钙调素介导,但慢钙通道在钙超载形成过程中也可能起一定作用。     

粉防己碱对豚鼠心室肌细胞延迟整流钾通道的影响

应用膜片钳全细胞记录技术研究了粉防己碱（ｔｅｔｒａｄｒｉｎｅ,Ｔｅｔ）对豚鼠心室肌细胞延迟整流钾电流（Ｉｋ）的影响。结果发现：（１）Ｔｅｔ１０－６ｍｏｌ／Ｌ对心室肌细胞Ｉｋ的外向部分有显著的激活作用。（２）Ｔｅｔ对Ｉｋ外向部分的激活作用呈剂量依赖性。阈浓度为３×１０－８ｍｏｌ／Ｌ,最大有效浓度为３×１０－５ｍｏｌ／Ｌ。（３）Ｔｅｔ使心室肌细胞Ｉｋ的外向部分呈时间依赖性增加。结果提示：Ｔｅｔ对Ｉｋ的外向部分有激活作用,这种激活作用可能是其降低心肌收缩力、抗高血压和抗心律失常的作用机制之一。     

川芎嗪对慢性缺氧豚鼠右室心肌细胞钾电流的影响

目的： 探讨慢性缺氧及川芎嗪长期应用对豚鼠右室心肌细胞钾电流的影响。方法：采用全细胞膜片钳技术分别记录并比较正常对照组、缺氧组、药物（ 川芎嗪） 治疗组豚鼠单个右室心肌细胞的膜电容、延迟整流钾电流峰值和电流－ 电压关系曲线及内向整流钾电流－ 电压关系曲线。结果：上述３ 组细胞膜电容分别为（１５４ ．９ ±１６ ．７） ｐＦ、（１７７ ．３ ±１４ ．３）ｐＦ、（１６０ ．５ ±１３ ．９）ｐＦ,其中缺氧组显著大于另两组（ Ｐ＜ ０－０１） ;延迟整流钾电流峰值分别为（１ ．１３ ±０ ．２９）ｎＡ、（０ ．７９ ±０ ．２１） ｎＡ、（１ ．０３ ±０ ．２３） ｎＡ,其中缺氧组显著低于另两组（ Ｐ＜ ０－０５） ;在－ ２０ ｍ Ｖ～＋ ６０ ｍ Ｖ,慢性缺氧组延迟整流钾电流密度较另两组显著下降（ Ｐ＜ ０－０５） 。３ 组之间的内向整流钾电流无显著差异（ Ｐ＞ ０－０５） 。结论： 慢性缺氧不改变豚鼠右室心肌细胞内向整流钾电流,但能使细胞膜电容增加,延迟整流钾电流幅度和电流密度下降;长期应用川芎嗪能在一定程度上减轻这些变化     

Experimental Study of Adenovirus Vector Mediated-hVEGF165 Gene on Prevention of Restenosis after Angioplasty

This study evaluated the effects of adenovirus vector mediated human vascular endotheli-al growth factor-165 (hVEGF165) gene on prevention of restenosis after angioplasty. Rabbit models of bilateral carotid artery injury were established by balloon denudation. The recombinant adenovi-ruses containing hVEGF165 cDNA was directly injected into left side of the injured carotid arteries.On day 3 and week 3 after transfection the expression of VEGF was observed by RT-PCR and im-munohistochemistry. The thrombokinesis, reendothelialization (rET) and intimal hyperplasia in ca-rotid arteries were evaluated by computerized image analysis system 3 weeks after gene transfer,The changes in the VEGF gene-treated side were compared with the control side. Our results showed that 3 days and 3 weeks after hVEGF165 gene transfer the VEGF mRNA and antigen ex-pression were detected in vivo. 3 weeks after the transfer, the carotid artery rET was markedly better in the VEGF gene-treated group compared with the control. The thrombokinesis, intima are-a/media area (I/M), maximal intimal and medial thicknesses (ITmax and MTmax) demonstrated a statistically significant decrease in arteries treated with VEGF gene as compared with the control group. It is concluded that VEGF gene transfer could be achieved by intra-arterial injection of re-combinant adenoviruses. It might accelerate the restoration of endothelial integrity, inhibit throm-bokinesis and attenuate intimal hyperplasia in the injured arteries after VEGF gene transfer. This procedure could be useful in preventing restenosis after angioplasty.     

The Ionic Basis of the Abnormal Electrophysiological Features of the Myocytes Isolated from the Right Ventricle of Chronic Hypoxia Guinea Pigs

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