目的评价瑞芬太尼对正常和高血压大鼠基底动脉平滑肌细胞上大电导钙激活钾通道(BKCa)和电压门控钾通道(Kv)激活电流的影响。方法自发性高血压大鼠(spontaneously hypertensive rats,SHR)和同源正常血压(wistar-kyoto,WKY)大鼠,采用酶消...目的评价瑞芬太尼对正常和高血压大鼠基底动脉平滑肌细胞上大电导钙激活钾通道(BKCa)和电压门控钾通道(Kv)激活电流的影响。方法自发性高血压大鼠(spontaneously hypertensive rats,SHR)和同源正常血压(wistar-kyoto,WKY)大鼠,采用酶消化法急性分离基底动脉平滑肌细胞,每种大鼠选择6个基底动脉平滑肌细胞,采用全细胞膜片钳技术记录外向电流幅度。加入瑞芬太尼3×10-7mol/L,分别记录所设置的方波刺激(step刺激)方案中所有刺激电压下给药前(基础水平)和给药后电流幅度,并计算净电流=给药后电流幅度-基础值;采用浓度累积法给药,分别记录+60 m V刺激电压下给药前(基础值)和给予10-10、10-9、10-8、10-7、10-6、10-5mol/L瑞芬太尼后电流幅度,计算电流增加率和瑞芬太尼增加基底动脉平滑肌细胞电流幅度的半数有效浓度(EC50);另取每种大鼠6个基底动脉平滑肌细胞,加入瑞芬太尼3×10-7mol/L后分别给予BKCa阻滞剂四乙胺(tetraethylammonium,TEA)和Kv阻滞剂4-氨基吡啶(4-aminopyridine,4-AP),再分别加入其相应的瑞芬太尼混合液,记录每一次给药后的电流幅度。结果两种大鼠基底动脉平滑肌细胞给瑞芬太尼后在0、+20、+40和+60 m V刺激电压下产生的净电流依次明显增大(P<0.05);10-10、10-9、10-8、10-7mol/L瑞芬太尼作用下,两种大鼠基底动脉平滑肌细胞外向电流增加率依次明显升高(P<0.05);与WKY大鼠比较,瑞芬太尼增加SHR基底动脉平滑肌细胞电流幅度的(EC50)明显升高(P<0.05);与基础值比较,两种大鼠基底动脉平滑肌细胞瑞芬太尼给药后电流幅度明显升高,TEA给药后或4-AP给药后电流幅度明显降低(P<0.05);与TEA给药后或4-AP给药后比较,TEA+瑞芬太尼给药后或4-AP+瑞芬太尼给药后两种大鼠基底动脉平滑肌细胞电流幅度明显升高(P<0.05)。结论瑞芬太尼呈电压依赖性和浓度依赖性激活两种大鼠基底动脉平滑肌细胞BKCa和Kv电展开更多
In this study, we investigated the effects of a combination of Ginkgo biloba extracts （GBE） and phosphodiesterase type 5 （PDE-5） inhibitors on the muscular tone of the corpus cavernosum and potassium channel activ...In this study, we investigated the effects of a combination of Ginkgo biloba extracts （GBE） and phosphodiesterase type 5 （PDE-5） inhibitors on the muscular tone of the corpus cavernosum and potassium channel activity of corporal smooth muscle cells. Strips of corpus cavernosum from male New Zealand white rabbits were mounted in organ baths for isometric tension studies. After contraction with 1 × 10^-5 mol I^-1 norepinephrine, GBE （0.01-1 mg ml^-1） and mirodenafil （0.01-100 nmol I^-1） were added together into the organ bath. In electrophysiological studies, whole-cell currents were recorded by the conventional patch-clamp technique in cultured smooth muscle cells of the human corpus cavernosum. The corpus cavemosum was relaxed in response to GBE in a dose-dependent manner （from 0.64%±8.35% at 0.01 mg ml^-1 to 52.28%±11.42% at 1 mg ml^-1）. After pre-treatment with 0.03 mg ml^-1 of GBE, the relaxant effects of mirodenafil were increased at all concentrations, After tetraethylammonium （TEA） （1 mmol I^-1） administration, the increased effects were inhibited （P〈0.01）. Extracellular administration of GBE increased the whole-cell K^＋ outward currents in a dose-dependent fashion. The increase of the outward current was inhibited by I mmol 1-1 TEA. These results suggest that GBE could increase the relaxant potency of mirodenafil even at a minimally effective dose. The K＋ flow through potassium channels might be one of the mechanisms involved in this synergistic relaxation.展开更多
文摘目的评价瑞芬太尼对正常和高血压大鼠基底动脉平滑肌细胞上大电导钙激活钾通道(BKCa)和电压门控钾通道(Kv)激活电流的影响。方法自发性高血压大鼠(spontaneously hypertensive rats,SHR)和同源正常血压(wistar-kyoto,WKY)大鼠,采用酶消化法急性分离基底动脉平滑肌细胞,每种大鼠选择6个基底动脉平滑肌细胞,采用全细胞膜片钳技术记录外向电流幅度。加入瑞芬太尼3×10-7mol/L,分别记录所设置的方波刺激(step刺激)方案中所有刺激电压下给药前(基础水平)和给药后电流幅度,并计算净电流=给药后电流幅度-基础值;采用浓度累积法给药,分别记录+60 m V刺激电压下给药前(基础值)和给予10-10、10-9、10-8、10-7、10-6、10-5mol/L瑞芬太尼后电流幅度,计算电流增加率和瑞芬太尼增加基底动脉平滑肌细胞电流幅度的半数有效浓度(EC50);另取每种大鼠6个基底动脉平滑肌细胞,加入瑞芬太尼3×10-7mol/L后分别给予BKCa阻滞剂四乙胺(tetraethylammonium,TEA)和Kv阻滞剂4-氨基吡啶(4-aminopyridine,4-AP),再分别加入其相应的瑞芬太尼混合液,记录每一次给药后的电流幅度。结果两种大鼠基底动脉平滑肌细胞给瑞芬太尼后在0、+20、+40和+60 m V刺激电压下产生的净电流依次明显增大(P<0.05);10-10、10-9、10-8、10-7mol/L瑞芬太尼作用下,两种大鼠基底动脉平滑肌细胞外向电流增加率依次明显升高(P<0.05);与WKY大鼠比较,瑞芬太尼增加SHR基底动脉平滑肌细胞电流幅度的(EC50)明显升高(P<0.05);与基础值比较,两种大鼠基底动脉平滑肌细胞瑞芬太尼给药后电流幅度明显升高,TEA给药后或4-AP给药后电流幅度明显降低(P<0.05);与TEA给药后或4-AP给药后比较,TEA+瑞芬太尼给药后或4-AP+瑞芬太尼给药后两种大鼠基底动脉平滑肌细胞电流幅度明显升高(P<0.05)。结论瑞芬太尼呈电压依赖性和浓度依赖性激活两种大鼠基底动脉平滑肌细胞BKCa和Kv电
文摘In this study, we investigated the effects of a combination of Ginkgo biloba extracts （GBE） and phosphodiesterase type 5 （PDE-5） inhibitors on the muscular tone of the corpus cavernosum and potassium channel activity of corporal smooth muscle cells. Strips of corpus cavernosum from male New Zealand white rabbits were mounted in organ baths for isometric tension studies. After contraction with 1 × 10^-5 mol I^-1 norepinephrine, GBE （0.01-1 mg ml^-1） and mirodenafil （0.01-100 nmol I^-1） were added together into the organ bath. In electrophysiological studies, whole-cell currents were recorded by the conventional patch-clamp technique in cultured smooth muscle cells of the human corpus cavernosum. The corpus cavemosum was relaxed in response to GBE in a dose-dependent manner （from 0.64%±8.35% at 0.01 mg ml^-1 to 52.28%±11.42% at 1 mg ml^-1）. After pre-treatment with 0.03 mg ml^-1 of GBE, the relaxant effects of mirodenafil were increased at all concentrations, After tetraethylammonium （TEA） （1 mmol I^-1） administration, the increased effects were inhibited （P〈0.01）. Extracellular administration of GBE increased the whole-cell K^＋ outward currents in a dose-dependent fashion. The increase of the outward current was inhibited by I mmol 1-1 TEA. These results suggest that GBE could increase the relaxant potency of mirodenafil even at a minimally effective dose. The K＋ flow through potassium channels might be one of the mechanisms involved in this synergistic relaxation.
