共查询到14条相似文献,搜索用时 718 毫秒
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叶培武 《浙江大学学报(医学版)》2019,48(1):5-11
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缺血再灌注处理对乳鼠心肌细胞钠电流的影响 总被引:2,自引:1,他引:1
目的研究缺血再灌注(I/R)处理对乳鼠心肌细胞钠电流的影响。方法实验分为两组:对照组为体外培养乳鼠心室肌细胞;I/R组为相同的细胞,缺血3 h,再灌注1 h,采用膜片钳全细胞模式记录仪分别记录并比较对照组和I/R组的钠电流。结果和对照组相比,I/R组在每一指令电压上都增大钠电流;在测试电压为-20 mV的条件下,钠电流峰值电流密度从(-159.74±63.80)pA/pF增至(-397.25±82.99)pA/pF(n=7,P(0.05);通道稳态激活V1/2分别为(-58.77±3.83)mV和(-51.51±5.34)mV(n=5,P(0.05);稳态失活V1/2分别为(-58.77±3.83)mV和(-51.51±5.34)mV(n=5,P(0.05);通道失活后恢复τ分别为(8.57±1.50)ms和(6.30±0.57)ms(n=5,P(0.05)。结论 I/R处理可以增大钠电流的峰值电流,并使电压电流曲线下移;减慢通道的时间依赖性激活,促进通道的电压依赖性失活,失活后恢复变快。钠通道的这些改变可能是引起心肌细胞缺血再灌注损伤的重要原因。 相似文献
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目的:观察异丙酚对大鼠海马锥体神经元低电压激活钙电流[low-voltage-activated calcium currents, I Ca(LVA) ]的影响。方法:培养Wistar大鼠海马锥体神经元,采用全细胞膜片钳技术测定I Ca(LVA) 。加用不同浓度(3、10、30、100、300 μmol/L)异丙酚后,计算I Ca(LVA)抑制率,建立异丙酚的浓度-效应曲线,选择20 μmol/L异丙酚作ICa(LVA)的激活及失活曲线。结果:3 μmol/L的异丙酚对I Ca(LVA)的电流幅度无影响;10、30、100、300 μmol/L的异丙酚对I Ca(LVA)的电流幅度抑制率分别为(12.6±4.1)%、(29.2±5.7)%、(36.6±5.3)%、(31.6±2.6)%。拟合后的浓度-效应曲线的IC50为16.8 μmol/L,Hill系数为0.15。激活曲线的半数最大激活膜电位(V 1/2)由(-10±1) mV 移动到(-11±2) mV;K分别为12±1和8±1;失活曲线的V 1/2分别为(-25±1) mV和(-25±5) mV,K分别为15±1和16±3。20 μmol/L异丙酚均未使I Ca(LVA)的激活曲线及稳态失活曲线发生明显移动。结论:异丙酚对I Ca(LVA)通道有抑制作用,异丙酚对中枢神经系统的麻醉作用可能与I Ca(LVA)抑制有关。 相似文献
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目的:观察氯胺酮对大鼠海马锥体神经元瞬间外向钾电流(IA)的影响。方法:酶消化法急性分离Wistar大鼠海马锥体神经元,采用全细胞膜片钳技术测定IA。加用不同浓度(10、30、100、300和1 000 μmol/L)氯胺酮后,计算IA抑制率,建立氯胺酮的浓度-效应曲线,选择30 μmol/L氯胺酮作IA稳态激活(及失活)曲线。结果:10 μmol/L的氯胺酮对IA的电流幅度无影响;30、100、300和1 000 μmol/L的氯胺酮对IA的电流幅度抑制率分别为(11±2)%、(22±3)%、(45±5)%和(53±5)%。IC50为(130±24)μmol/L, Hill系数为1.19±0.56。30 μmol/L氯胺酮使激活曲线的半数最大激活膜电位(V 1/ 2)从(-8.70±0.13) mV 移动到 (-11.2±2.10) mV (n=8, P<0.05), K从(15.0±4.6) mV移动到(17.6±5.7)mV (n=8, P>0.05);失活曲线的V 1/2从(-75.53±7.98) mV移动到(-91.94±11.85) mV(n=8, P < 0.05),K从(10.5±2.2) mV移动到(8.0±1.2) mV(n=8, P>0.05)。30 μmol/L氯胺酮使IA的激活和失活曲线均向超极化方向明显移动。 结论: 临床浓度的氯胺酮能够同时加速IA的激活和失活过程,但加速IA失活的能力大于其加速IA激活的能力。氯胺酮对中枢神经系统的作用可能与IA抑制有关。 相似文献
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目的:观察尼可刹米对新生大鼠海马神经元电压依赖性钠通道的影响.方法:制备大鼠海马脑组织切片,灌流含5 mg/L尼可刹米的人工脑脊液,应用全细胞膜片钳技术记录给药前、给药后10 min脑组织切片海马神经元电压依赖性钠电流,绘制给药前后钠通道的钠电流一测试电压(I-V)曲线、稳态激活曲线和稳态失活曲线.结果:尼可刹米在脑电位-50-+20 mV范围内增大钠电流.尼可刹米使钠通道稳态激活曲线中钠通道半数激活电压由(-34.6±3.07)mV变为(-37.63±3.37)mV(t=3.38,P=0.02),曲线向超极化方向变化;尼可刹米使钠通道的稳态失活曲线中钠通道半数失活电压由(-43.36±3.06)mV变为(-33.24±2.05)mV(t=6.13,P=0.002),曲线向去极化方向变化.结论:增加电压依赖性钠电流可能是尼可刹米兴奋中枢神经元的作用机制之一. 相似文献
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REN Fu-xian NIU Xiao-lin OU Yan XIE Song-mei LING Feng-dong ZHOU Shi-sheng LI Ya-jie 《中华医学杂志(英文版)》2008,121(21):2185-2191
Background Few studies have explored the inward sodium current (INa) kinetics of transitional cardiomyocytes. This study aimed to explore the kinetics of transitional cardiomyocytes types α and β. Methods The whole-cell patch clamp technique was used to study the rapid INa of isolated transitional cardiomyocytes in the Koch triangle of rabbit hearts. Results Maximal amplitude and density of INa in type a and type β was (-1627±288) pA (α), (-35.17±6.56) pA/pF (β) and (-3845±467) pA (α), (-65.64±10.23) pA/pF (β) (P 〈0.05). Steady state activation curves of INa, fitted to a Boltzmann distribution for both types, were sigmoid in shape. Half activation voltage and slope factors did not significantly differ between types at (-43.46±0.85) mV (α), (-41.39±0.47) mV (β) or (9.04±0.66) mV (α), (11.08±0.89) mV (β). Steady state inactivation curves of INa, fitted to a Boltzmann distribution in both types were inverse "S" shape. Half inactivation voltage and slope factors were (-109.9±0.62) mV (α), (-107.5±0.49) mV (β) and (11.78±0.36) mV (α), (11.57±0.27) mV (β), (P〉0.05), but time constants of inactivation were significantly different at (1.10±0.19) mV (α) and (2.37±0.33) ms (β), (P 〈0.05). Time constants of recovery from inactivation of INa for both types were (122.16±27.43) mV (α) and (103.84±2.8.97) ms (β) (P 〈0.05).
Conclusions Transitional cardiomyocytes in rabbit hearts show a heterogeneous, voltage gated and time dependent fast inward sodium current. Types α and β show the features of INa similar to those in slow- and fast-response myocytes, with probably better automaticity and conductivity, respectively. 相似文献
Conclusions Transitional cardiomyocytes in rabbit hearts show a heterogeneous, voltage gated and time dependent fast inward sodium current. Types α and β show the features of INa similar to those in slow- and fast-response myocytes, with probably better automaticity and conductivity, respectively. 相似文献
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