摘要
目的探讨正常大鼠冠状动脉平滑肌细胞钾离子通道的组成及二十二碳六烯酸(DHA)的激活作用。方法采用酶消化法急性分离正常大鼠冠状动脉平滑肌细胞,以全细胞膜片钳技术记录灌流不同钾离子通道阻滞剂后钾离子通道电流的变化,以及DHA灌流后钾离子通道电流变化。结果未加阻滞剂时,5μmol/LDHA灌流后钾离子通道电流明显增加,在刺激电压为100mV时,DHA灌流前后的电流密度分别为(52.80±6.68)和(110.09±13.39)pA/pF(P〈0.05)。在非特异性钾离子通道阻滞剂四乙胺10mmol/L作用下,DHA灌流不能激活钾离子通道。与未灌流时基础状态比较,在大电导钙激活钾离子通道特异性阻滞剂ibritoxin100nmol/L、中电导钙激活钾离子通道阻滞剂TRAM-34200nmol/L、小电导钙激活钾离子通道阻滞剂apamin1μmol/L、电压依赖性钾离子通道阻滞剂4-aminopyridine5mmol/L和ATP依赖性钾离子通道阻滞剂glyburide10μmlol/L作用下,钾离子通道电流密度分别减少47.6%、12.4%、13.6%、41.5%和0.1%,再同时灌流DHA后钾离子通道电流密度分别增加32.4%、124.2%、108.5%、149.5%和144.7%。结论大电导钙激活钾离子通道与电压依赖性钾离子通道为正常大鼠冠状动脉平滑肌细胞上分布的主要的钾离子通道。DHA可激活冠状动脉平滑肌细胞钾离子通道,其中主要为大电导钙激活钾离子通道,这可能是DHA扩张冠状动脉、保护心血管系统的机制之一。
Objective To investigate the composition of potassium channels in normal rat coronary smooth muscle cells (CASMCs) and the activation effects of docosahexaenoic acid (DHA). Methods CASMCs were isolated by enzyme digestion. Effects of different types of potassium channel blockers and/or DHA on potassium channels currents were studied by whole-cell patch clamp technique. Results Potassium currents were significantly increased with 5μmol/L DHA peffusion ( P 〈0. 05 ). The current density was increased from (52. 80 ±6. 68) pA/pF to ( 110. 09 ± 13.39) pA/pF (P 〈0. 05) after DHA perfusion when the stimulation voltage was 100 inV. Compared with baseline, potassium currents were significantly decreased by various inhibitor peffusion ( tetraethylammonium : ( 49.63 ± 5.75 ) pA/pF vs. ( 13.96 ± 2. 18 ) pA/pF ;ibritoxin : ( 50. 67 ± 7. 89 ) pA/pF vs. (26.53 ±4.68) pA/pF; TRAM-34:(52.60±7.02) pA/pF vs. (46. 05 ± 7.60) pA/pF ; apamin : ( 51.97 ± 3.83 ) pA/pF vs. ( 44. 89 ± 5.04 ) pA/pF ; 4-aminopyridine : (51.19 ±3.44) pA/pF vs. (29. 92 ± 2. 81) pA/pF; glyburide: (49.67 ± 1.77) pA/pF vs. (49.61 ± 1.87) pA/pF, all P 〈 0. 05 ). In presence of different inhibitors, potassium channel current densities were increased after DHA perfusion except tetraethylammonium (tetraethylammonium: ( 12. 79± 1.89 ) pA/pF; ibritoxin:(67.08 ± 5.54) pA/pF; TRAM-34: ( 117.91 ± 21.79) pA/pF; apamin: ( 108.33 ± 7.06) pA/pF; 4-aminopyridine: ( 127.73 ± 20. 56) pA/pF; glyburide : ( 121.53 ± 13.83 ) pA/pF, all P 〈 0. 05 compared with baseline ). Conclusions Large-conductance calcium-activated potassium channel and voltage-gated potassium channel are the major constituents of potassium channels in CASMCs. DHA can activate potassium channels in CASMCs, mainly the large conductance calcium-activated potassium channel, thus dilate coronary arteries.
出处
《中华心血管病杂志》
CAS
CSCD
北大核心
2016年第7期600-604,共5页
Chinese Journal of Cardiology
基金
国家自然科学基金(81370303,81500249,81400297,81500323)
江苏省自然科学基金(BK20151110)
江苏省人事厅“六大人才高峰”第七批高层次项目(006)
江苏省医学重点人才资助项目(RC201134)
南京医科大学科技发展基金重点项目(2013NJMU153)
关键词
冠状血管
肌细胞
平滑肌
钾通道
二十二碳六烯酸类
膜片钳术
Coronary vessels
Myocytes, smooth muscle
Potassium channels
Docosahexaenoicacids
Patch-clamp techniques