Shen Bing, Fu Jie, Guo Jizheng, Zhang Jie, Wang Xia, Pan Xiang, Chen Meihua, Zhou Yifan, Zhu Min, Du Juan
Department of Physiology, Anhui Medical University, Hefei, Anhui, China.
Cell Physiol Biochem. 2015;37(2):747-58. doi: 10.1159/000430392. Epub 2015 Sep 11.
BACKGROUND/AIMS: Vasoconstrictor-induced rhythmic contraction of arteries or veins has been observed both in vivo and in vitro. Many studies have reported that gap junctions, ryanodine receptors, Na+, K+-ATPase and other factors are involved in vasoconstrictor-induced rhythmic contraction in vascular smooth muscle. However, the mechanism is still not completely understood.
We used vessel tension measurements, intracellular recordings and intracellular Cl- concentration ([Cl-]i) measurements to investigate the mechanism underlying phenylephrine (PE)-induced rhythmic contraction in the mouse aorta.
We found that Na+-K+-2Cl- cotransporter 1 (NKCC1) inhibitor bumetanide abolished PE-induced rhythmic contraction. The Cl- channel blockers DIDS and niflumic acid initially augmented the amplitude of PE-induced rhythmic contraction but later inhibited the rhythmic contraction. The large Ca2+-activated K+ channel blocker TEA and iberiotoxin increased the amplitude of PE-induced rhythmic contraction. The voltage-dependent Ca2+ channel blocker, nifedipine, and a Ca2+-free solution abolished PE-induced rhythmic contraction. The inhibitor of ryanodine receptors in the sarcoplasmic reticulum, ryanodine, inhibited PE-induced rhythmic contraction. Moreover, bumetanide hyperpolarized the membrane potential of vascular smooth muscle cells in a resting state or after PE pre-treatment. Bumetanide, niflumic acid, ryanodine, iberiotoxin, nifedipine and Ca2+-free buffer significantly suppressed the PE-induced [Cl-]i increase.
These data indicate that NKCC1 is involved in the formation of PE-induced rhythmic contraction, and we also provide a method with which to indirectly observe the NKCC1 activity in isolated intact mouse thoracic aortas.
背景/目的：体内和体外实验均观察到血管收缩剂可诱导动脉或静脉产生节律性收缩。许多研究报道，缝隙连接、兰尼碱受体、钠钾ATP酶及其他因素参与了血管收缩剂诱导的血管平滑肌节律性收缩。然而，其机制仍未完全明确。
我们采用血管张力测量、细胞内记录及细胞内氯离子浓度（[Cl-]i）测量等方法，研究去氧肾上腺素（PE）诱导的小鼠主动脉节律性收缩的机制。
我们发现钠钾氯共转运体1（NKCC1）抑制剂布美他尼可消除PE诱导的节律性收缩。氯离子通道阻滞剂二碘硝基酚（DIDS）和氟尼酸最初可增大PE诱导的节律性收缩幅度，但随后会抑制该节律性收缩。大电导钙激活钾通道阻滞剂四乙铵（TEA）和iberiotoxin可增大PE诱导的节律性收缩幅度。电压依赖性钙通道阻滞剂硝苯地平及无钙溶液可消除PE诱导的节律性收缩。肌浆网中兰尼碱受体的抑制剂兰尼碱可抑制PE诱导的节律性收缩。此外，布美他尼可使静息状态或经PE预处理后的血管平滑肌细胞膜电位超极化。布美他尼、氟尼酸、兰尼碱、iberiotoxin、硝苯地平和无钙缓冲液可显著抑制PE诱导的[Cl-]i升高。
这些数据表明NKCC1参与了PE诱导的节律性收缩的形成，并且我们还提供了一种间接观察分离的完整小鼠胸主动脉中NKCC1活性的方法。
