The stimulation of cathecholamine release from chromaffin granules by valinomycin.
The stimulation of cathecholamine release from chromaffin granules by valinomycin.
复制标题
缬氨霉素刺激嗜铬颗粒释放儿茶酚胺。
作者：
J. Dolais;R. Perlman
缬霉素刺激体外培养豚鼠肾上腺髓质染色质颗粒中儿茶酚胺的释放。缬霉素刺激的儿茶酚胺释放依赖于离子载体浓度和培养介质中K +的浓度。在0.15 M KCl-5 mM Na·PO 4, pH 7.0中，1µM的valinomycin使儿茶酚胺释放量增加约5倍。发现儿茶酚胺的释放伴随着腺嘌呤核苷酸和多巴胺β-羟化酶从染色质颗粒的释放，表明缬霉素诱导颗粒的裂解。缬霉素对儿茶酚胺释放的影响也取决于培养培养基中存在的阴离子。所测试的阴离子支持valinomycin刺激的儿茶酚胺释放，其顺序为SCN -， I -, Br - > Cl - >醋酸盐，F -，异乙硫酸盐。这些数据表明，在膜渗透性阴离子存在的情况下，缬霉素介导的K +转运进入染色质颗粒导致这些颗粒的渗透裂解。
Valinomycin stimulates the release of catecholamine from isolated guinea pig adrenal medullary chromaffin granules incubated in vitro . Valinomycin-stimulated catecholamine release is dependent on the ionophore concentration and on the concentration of K + in the incubation medium. In. 0.15 M KCl-5 mM Na·PO 4 , pH 7.0, valinomycin at 1 µM increases catecholamine release about 5-fold. The finding that catecholamine release is accompained by the release of adenine nucleotides and of dopamine β-hydroxylase from the chromaffin granules indicates that valinomycin induces the lysis of the granules. The effect of valinomycin on catecholamine release is also dependent upon the anions present in the incubation medium. The anions tested support valinomycin-stimulated catecholamine release in the order SCN - , I - , Br - > Cl - > acetate, F - , isethionate. These data suggest that, in the presence of a membrane-permeable anion, valinomycin-mediated transport of K + into chromaffin granules leads to the osmotic lysis of these granules.