Effects of external pH on ionic currents in smooth muscle cells from the basilar artery of the guinea pig.
Effects of external pH on ionic currents in smooth muscle cells from the basilar artery of the guinea pig.
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外部 pH 值对豚鼠基底动脉平滑肌细胞离子电流的影响。
DOI：
10.1161/01.res.71.1.201
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发表时间：
1992
影响因子：
20.1
通讯作者：
Simard,JM
中科院分区：
文献类型：
--
作者：
West,GA;Leppla,DC;Simard,JM
PHO是脑血管张力的重要决定因素。我们观察了pho的变化对豚鼠基底动脉分离的平滑肌细胞的影响。单个细胞在PHO(恒定二氧化碳浓度)升高时迅速收缩，硝苯地平可阻断收缩，提示二氢吡啶敏感的钙通道起作用。在全细胞膜片钳实验中，改变pho(pho 5.7-8.1，phi 7.2，10 mM HEPES)强烈影响钙通道电流(10 mM Ba2+，+15 mV，保持电位-55 mV)的幅度，其表观pK为6.9。电流-电压曲线最小位移，表明表面电荷没有重要影响。为了分离缓慢失活的L型钙通道电流和快速失活的B型电流，用重复1秒脉冲(+15 mV，保持电位-55 mV)研究的细胞内向电流的衰减部分符合二分量模型。L电流和B型电流的滴定曲线在碱性磷酸时分别增加了3.65和1.28倍，表观pK值分别为7.71和6.47(希尔系数)。+15 mV时B型电流的失活时间常数受pho的影响不大，而L电流的失活时间常数随pho的增加而略有增加。其他实验表明，pho对保持电流或电压激活的外向电流(pCaI 7，11 mM EGTA)没有显著影响。我们的结果为钙通道参与调节脑血管平滑肌基础张力提供了进一步的证据，并表明pho通过缓慢失活二氢吡啶敏感的L型钙通道来调节电流。
pHo is an important determinant of vascular tone in cerebral blood vessels. We investigated the effects of changes in pHo on isolated smooth muscle cells from the basilar artery of the guinea pig. Single cells contracted rapidly in response to an elevation in pHo (constant CO2), and contraction was blocked by nifedipine, suggesting a role for dihydropyridine-sensitive Ca2+ channels. In whole-cell patch-clamp experiments, changes in pHo (pHo 5.7-8.1, pHi 7.2 with 10 mM HEPES) strongly affected the amplitude of the peak Ca2+ channel current (10 mM Ba2+, +15 mV, holding potential of -55 mV), with an apparent pK of 6.9. The current-voltage curves were minimally shifted, indicating no important effect of surface charge. To separate the slowly inactivating L-type Ca2+ channel current from the more rapidly inactivating B-type current, the decaying portions of inward currents from cells studied with repetitive 1-second pulses (+15 mV, holding potential of -55 mV) were fit to a two-component model. Titration curves for the L-type and B-type currents indicated maximum increases by factors of 3.65 and 1.28 at alkaline pHo and gave apparent pK values of 7.71 and 6.47 (Hill coefficient unity). The time constant of inactivation for the B-type current at +15 mV was little affected by pHo, whereas that for the L-type current increased somewhat with increasing pHo. Additional experiments showed no significant effect of pHo on holding current or on voltage-activated outward currents (pCai 7 with 11 mM EGTA). Our results provide additional evidence for participation of Ca2+ channels in regulating basal tone in cerebral smooth muscle and indicate that pHo regulates current through slowly inactivating, dihydropyridine-sensitive L-type Ca2+ channels.
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豚鼠单心室肌细胞内质子对钙通道的抑制
影响因子：
1.7
作者：
貝原 宗重
通讯作者：
貝原 宗重
影响因子：
3.8
作者：
TYTGAT, J;NILIUS, B;CARMELIET, E
通讯作者：
CARMELIET, E
脑细胞外pH：控制脑血流量的主要因素。
影响因子：
2.1
作者：
Niels A. Lassen
通讯作者：
Niels A. Lassen
二氢吡啶尼古地平调节血管平滑肌细胞中的钙电流和钾电流
影响因子：
7.3
作者：
U. Klöckner;G. Isenberg
通讯作者：
G. Isenberg
K 通道激动剂克罗卡林和吡那地尔对大鼠基底动脉平滑肌细胞的作用是由 Ca(+) 激活的 K 通道介导的。
DOI：
10.1016/s0006-291x(05)81397-x
发表时间：
1991
影响因子：
3.1
作者：
N. Stockbridge;H. Zhang;B. Weir
通讯作者：
B. Weir