MORPHOLOGICAL CHANGES OF CULTURED MYOCARDIAL CELLS DUE TO CHANGE IN EXTRACELLULAR CALCIUM ION CONCENTRATION |
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Authors: | KIYOTA GOSHIMA HACHIRO YAMANAKA GORO EGUCHI SHIGEO YOSHINO |
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Institution: | Institute of Molecular Biology, Nagoya University, Chikusaku, Nagoya 464, Japan;Department of Physics, Faculty of Science, Nagoya University, Chikusaku, Nagoya 464, Japan |
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Abstract: | Increase in the extracellular Ca2+ concentration from low (≤ 10?7 M) to normal (10?3 M) caused morphological changes of cultured myocardial cells obtained from fetal mouse heart. The extracellular Na+ and K+ concentrations of the normal medium (10?3 M Ca2+) did not significantly affect the genesis of these morphological changes. Like Ca2+, Ba2+ and Sr2+, but not Mg2+, Co2+ or Ni2+, could induce morphological changes. Increase in the extracellular Ca2+ concentration from 10?8 M to 10?3M also caused excess uptake of 45Ca2+ by cultured myocardial cells. B–16CW 1 cells, which did not show these morphological changes, did not take up excess 45Ca2+ on this treatment. Treatments, such as addition of verapamil or incubation at pH 6.3, which reduced the genesis of morphological changes, reduced the rate of 45Ca2+ uptake by myocardial cells. These facts show that the morphological changes of myocardial cells induced by increasing the extracellular Ca2+ concentration from low to normal are due to excess uptake of Ca2+ by the myocardial cells. The morphological changes of cultured myocardial cells induced by increasing the extracellular Ca2+ concentration from low to normal were reversed on further incubation of the cells in medium with or without Ca2+. |
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