Departamento de Farmacología, Universidad Complutense, av. Séneca 2, 28040 Madrid, Spain.
Department of Anesthesiology, Pharmacology, and Therapeutics, The University of British Columbia, 2176 Health Sciences Mall, Medical Block C, Vancouver, BC V6T 1Z3, Canada.
Biochem Biophys Res Commun. 2014 Feb 28;445(1):84-8. doi: 10.1016/j.bbrc.2014.01.150. Epub 2014 Feb 4.
Phenylephrine (PE)-induced oscillatory fluctuations in intracellular Ca(2+) concentration ([Ca(2+)]i) of vascular smooth muscle have been observed in many blood vessels isolated from a wide variety of mammals. Paradoxically, until recently similar observations in humans have proven elusive. In this study, we report for the first time observations of adrenergically-stimulated [Ca(2+)]i oscillations in human mesenteric artery smooth muscle. In arterial segments preloaded with Fluo-4 AM and mounted on a myograph on the stage of a confocal microscope, we observed PE-induced oscillations in [Ca(2+)]i, which initiated and maintained vasoconstriction. These oscillations present some variability, possibly due to compromised health of the tissue. This view is corroborated by our ultrastructural analysis of the cells, in which we found only (5 ± 2)% plasma membrane-sarcoplasmic reticulum apposition, markedly less than measured in healthy tissue from laboratory animals. We also partially characterized the oscillations by using the inhibitory drugs 2-aminoethoxydiphenyl borate (2-APB), cyclopiazonic acid (CPA) and nifedipine. After PE contraction, all drugs provoked relaxation of the vessel segments, sometimes only partial, and reduced or inhibited oscillations, except CPA, which rarely caused relaxation. These preliminary results point to a potential involvement of the sarcoplasmic reticulum Ca(2+) and inositol 1,4,5-trisphosphate receptor (IP3R) in the maintenance of the Ca(2+) oscillations observed in human blood vessels.
苯肾上腺素（PE）诱导的血管平滑肌细胞内钙离子浓度（[Ca2+]i）的振荡波动已在从多种哺乳动物中分离的许多血管中观察到。矛盾的是，直到最近，人类中类似的观察结果仍难以捉摸。在这项研究中，我们首次报道了人类肠系膜动脉平滑肌中肾上腺素能刺激的[Ca2+]i 振荡。在动脉段中预先加载 Fluo-4 AM 并安装在共聚焦显微镜台上的肌动描记器上，我们观察到 PE 诱导的 [Ca2+]i 振荡，其引发并维持血管收缩。这些振荡存在一些可变性，可能是由于组织的健康状况受损。这一观点得到了我们对细胞的超微结构分析的证实，在该分析中，我们发现只有（5±2）%的质膜-肌浆网附着，明显低于从实验室动物的健康组织中测量的值。我们还通过使用抑制药物 2-氨基乙氧基二苯硼酸盐（2-APB）、环孢素 A（CPA）和硝苯地平来部分表征这些振荡。在 PE 收缩后，所有药物都会引起血管段的松弛，有时只是部分松弛，并减少或抑制振荡，除了 CPA，它很少引起松弛。这些初步结果表明，肌浆网 Ca2+和肌醇 1,4,5-三磷酸受体（IP3R）可能参与维持人类血管中观察到的 Ca2+振荡。
