<Originals>Calcium-induced Contraction in the Isolated Guinea-Pig Vas Deferens Pretreated with Tetrasodium Edetate

概要

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The additional of CaCl_2 to the medium induces no contraction in the isolated guinea-pig vas deferens when the preparation is suspended in Locke's solution, but induces a contraction when it has been pretreated with tetrasodium edetate and then transferred to an edetate-free sucrose medium. The contraction is concentration-dependent on the added CaCl_2,and decreases with increasing the time after the edetate-pretreatment. It was examined in the present study the relation between the concentration of the edetate and the contraction induced by the added CaCl_2. When 0.0001,0.001,0.003,0.01 and 0.1%(w/v) of tetrasodium edetate were used for the pretreatment for 20 min, the CaCl_2-induced contraction increased with increasing the concentration of the edetate. When the edetate-pretreatment was done in Ca- and K-free Locke's solution or in Ca-free Locke's solution in place of the sucrose medium, or when the tetrasodium edetate was replaced by calcium edetate, the CaCl_2-induced contraction was only a slight. These results may suggest that the calcium-induced contraction in the smooth muscle of vas deferens depends on the reduction of tissue calcium ions, and that the release of tissue calcium ions is inhibited by the presence of sodium ions in the medium.
近畿大学の論文
1979-09-28