Watanabe S, Tomono M, Takeuchi M, Kitamura T, Hirose M, Miyazaki A, Namihisa T
Department of Medicine, Juntendo University, Tokyo, Japan.
Liver. 1988 Jun;8(3):178-83. doi: 10.1111/j.1600-0676.1988.tb00988.x.
Dynamic contractions of bile canaliculi have been observed in cultured doublet hepatocytes by means of time-lapse cinephotomicrography, and this contractile movement plays an important role in bile secretion. Although details of the mechanism are still unknown, the Ca2+-calmodulin system is believed to play a main role in this mechanism. In this study we measured the intracellular Ca2+ concentration of individual doublet hepatocytes using the Ca2+ indicator "fura 2" and microscopic fluorometry. We also observed the effects of A23187, norepinephrine and epinephrine on bile canalicular contraction and intracellular Ca2+ concentration. After loading 1 mumol/l fura 2 in doublet cells, we added A23187, epinephrine or norepinephrine and then measured the Ca2+ concentration in a given small area in the cytoplasm of individual doublet cell. A23187, norepinephrine and epinephrine caused a prompt increase of the intracellular Ca2+ concentration and also caused bile canalicular contraction. The present study indicates that the sudden increase of intracellular Ca2+ concentration causes bile canalicular contraction through the Ca2+-calmodulin system.
通过延时电影显微摄影术，在培养的双联体肝细胞中观察到胆小管的动态收缩，并且这种收缩运动在胆汁分泌中起重要作用。尽管其机制的细节仍不清楚，但钙-钙调蛋白系统被认为在该机制中起主要作用。在本研究中，我们使用钙指示剂“fura 2”和显微荧光测定法测量了单个双联体肝细胞的细胞内钙浓度。我们还观察了A23187、去甲肾上腺素和肾上腺素对胆小管收缩和细胞内钙浓度的影响。在双联体细胞中加载1 μmol/l的fura 2后，我们加入A23187、肾上腺素或去甲肾上腺素，然后测量单个双联体细胞细胞质中给定小区域内的钙浓度。A23187、去甲肾上腺素和肾上腺素导致细胞内钙浓度迅速升高，并且还引起胆小管收缩。本研究表明，细胞内钙浓度的突然升高通过钙-钙调蛋白系统引起胆小管收缩。
