Alteration of cytoplasmic ionized calcium levels in smooth muscle by vasodilators in the ferret.
Alteration of cytoplasmic ionized calcium levels in smooth muscle by vasodilators in the ferret.
复制标题
雪貂血管扩张剂改变平滑肌细胞质离子钙水平。
DOI：
10.1113/jphysiol.1984.sp015516
复制
发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Morgan,KG
中科院分区：
文献类型：
--
作者：
Morgan,JP;Morgan,KG
水母发光蛋白被用作雪貂门静脉钾去极化条中血管扩张剂作用期间细胞质Ca 2+水平的指示剂。中等浓度的异丙肾上腺素在平滑肌松弛过程中产生的细胞质Ca 2+水平没有变化或增加。只有在极高浓度的异丙肾上腺素（大于10（-4）M）存在下，才可检测到细胞内Ca 2+水平的降低。罂粟碱和毛喉素也引起肌肉松弛，而细胞质钙离子水平观察到要么不改变或增加。当肌肉放松时，无论是通过降低沐浴介质中的钙浓度，还是通过加入硝普钠，光和力都下降了。力与光的比率是更大的肌肉放松时，钙耗尽比添加硝普钠，表明硝普钠放松肌肉不仅仅是降低细胞质Ca 2+水平。这些结果表明，并非所有血管扩张剂都会导致细胞质Ca 2+水平降低，并表明在完整细胞中，与细胞质cAMP水平升高相关的药物可导致钙-力关系的解偶联。
Aequorin was used as an indicator of cytoplasmic Ca2+ levels during the action of vasodilators in potassium‐depolarized strips of ferret portal vein. Moderate concentrations of isoprenaline produced either no change or an increase in cytoplasmic Ca2+ levels during smooth muscle relaxation. Only in the presence of very high concentrations of isoprenaline (greater than 10(‐4) M) was a decrease in intracellular Ca2+ levels detectable. Both papaverine and forskolin also caused relaxations of the muscle while cytoplasmic Ca2+ levels were observed either not to change or to increase. When the muscles were relaxed either by decreasing the calcium concentration in the bathing medium or by the addition of sodium nitroprusside, light and force fell together. The ratio of force to light was greater when the muscle was relaxed with calcium depletion than with the addition of sodium nitroprusside, indicating that sodium nitroprusside was relaxing the muscle by more than just decreasing cytoplasmic Ca2+ levels. These results indicate that not all vasodilators cause a lowering of cytoplasmic Ca2+ levels and indicate that, in intact cells, agents associated with increases in cytoplasmic cyclic AMP levels can cause an uncoupling of calcium‐force relations.