Snetkov Vladimir A, Aaronson Philip I, Ward Jeremy P T, Knock Gregory A, Robertson Tom P
Department of Asthma, Allergy and Respiratory Science, GKT School of Medicine, Centre for Cardiovascular Biology and Medicine, Guy's Hospital Campus, London SE1 9RT.
Br J Pharmacol. 2003 Sep;140(1):97-106. doi: 10.1038/sj.bjp.0705408. Epub 2003 Jul 29.
(1) The effect of induction of capacitative Ca2+ entry (CCE) upon tone in small (i.d. 200-500 microm) intrapulmonary (IPA), mesenteric (MA), renal (RA), femoral (FA), and coronary arteries (CA) of the rat was examined. (2) Following incubation of IPA with 100 nm thapsigargin (Thg) in Ca2+-free physiological salt solution (PSS), a sustained contraction was observed upon reintroduction of 1.8 mm Ca2+, which was unaffected by either diltiazem (10 microm) or the reverse mode Na+/Ca2+ antiport inhibitor KB-R7943 (10 microm). An identical protocol failed to elicit contraction in MA, RA, or CA, while a small transient contraction was sometimes observed in FA. (3) The effect of this protocol on the intracellular Ca2+ concentration ([Ca2+]i) was assessed using Fura PE3-loaded IPA, MA, and FA. Reintroduction of Ca2+ into the bath solution following Thg treatment in Ca2+-free PSS caused a large, rapid, and sustained increase in [Ca2+]i in all the three types of artery. (4) 100 nm Thg induced a slowly developing noisy inward current in smooth muscle cells (SMC) isolated from IPA, which was due to an increase in the activity of single channels with a conductance of approximately 30 pS. The current had a reversal potential near 0 mV in normal PSS, and persisted when Ca2+-dependent K+ and Cl- currents were blocked; it was greatly inhibited by 1 microm La3+, 1 microm Gd3+, and the IP3 receptor antagonist 2-APB (75 microm), and by replacement of extracellular cations by NMDG+. (5) In conclusion, depletion of intracellular Ca2+ stores with Thg caused capacitative Ca2+ entry in rat small muscular IPA, MA, and FA. However, a corresponding contraction was observed only in IPA. CCE in IPA was associated with the development of a small La3+- and Gd3+-sensitive current, and an increased Mn2+ quench of Fura PE-3 fluorescence. These results suggest that although CCE occurs in a number of types of small arteries, its coupling to contraction appears to be of particular importance in pulmonary arteries.
(1) 研究了诱导性钙库操纵性钙内流（CCE）对大鼠小口径（内径200 - 500微米）肺内动脉（IPA）、肠系膜动脉（MA）、肾动脉（RA）、股动脉（FA）和冠状动脉（CA）张力的影响。(2) 在无钙生理盐溶液（PSS）中，将IPA与100纳米毒胡萝卜素（Thg）孵育后，重新加入1.8毫摩尔钙时观察到持续收缩，该收缩不受地尔硫䓬（10微摩尔）或反向模式钠/钙交换体抑制剂KB - R7943（10微摩尔）的影响。相同方案未能在MA、RA或CA中引发收缩，而在FA中有时观察到小的瞬时收缩。(3) 使用负载Fura PE3的IPA、MA和FA评估该方案对细胞内钙浓度（[Ca2 +]i）的影响。在无钙PSS中用Thg处理后，将钙重新引入浴液会导致所有三种类型动脉中的[Ca2 +]i大幅、快速且持续增加。(4) 100纳米Thg在从IPA分离的平滑肌细胞（SMC）中诱导出缓慢发展的嘈杂内向电流，这是由于单个通道活性增加，其电导约为30皮安。在正常PSS中，该电流的反转电位接近0毫伏，当钙依赖性钾电流和氯电流被阻断时仍持续存在；它受到1微摩尔La3 +、1微摩尔Gd3 +和肌醇三磷酸受体拮抗剂2 - APB（75微摩尔）以及用NMDG +替代细胞外阳离子的强烈抑制。(5) 总之，用Thg耗尽细胞内钙库会导致大鼠小肌性IPA、MA和FA中的钙库操纵性钙内流。然而，仅在IPA中观察到相应的收缩。IPA中的CCE与小的对La3 +和Gd3 +敏感的电流的产生以及Fura PE - 3荧光的Mn2 +淬灭增加有关。这些结果表明，尽管CCE发生在多种类型的小动脉中，但其与收缩的偶联在肺动脉中似乎尤为重要。
