Deth R, van Breemen C
J Membr Biol. 1977 Jan 28;30(4):363-80. doi: 10.1007/BF01869677.
The effects of hormonal agonists (norepinephrine, angiotensin, and histamine) on 45Ca efflux from the rabbit aorta were studied using a Ca-EGTA buffered efflux medium. Each caused a transient stimulation of efflux rate which probably reflected the release of an intracellular 45Ca store. The size of the stimulation of efflux correlated with the size of the initial rapid phase of contraction. The norepinephrine-sensitive intracellular Ca fraction was estimated to be greater than 21 mumoles/Kg wet tissue weight. This fraction is separate from intracellular Ca which is accumulated during relaxation. Evidence is presented for the lack of cyclic nucleotide involvement in the release of Ca2+, and possible alternative modes of coupling are discussed.
使用钙-乙二醇双乙酸盐缓冲流出介质，研究了激素激动剂（去甲肾上腺素、血管紧张素和组胺）对兔主动脉45Ca流出的影响。每种激动剂均引起流出速率的短暂刺激，这可能反映了细胞内45Ca储存的释放。流出刺激的大小与收缩初始快速期的大小相关。据估计，对去甲肾上腺素敏感的细胞内钙部分大于21微摩尔/千克湿组织重量。该部分与舒张期积累的细胞内钙是分开的。文中提供了证据表明环核苷酸不参与Ca2+的释放，并讨论了可能的替代偶联模式。
