Colliver T L, Pyott S J, Achalabun M, Ewing A G
Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
J Neurosci. 2000 Jul 15;20(14):5276-82. doi: 10.1523/JNEUROSCI.20-14-05276.2000.
It has been well established that the volume of secretory vesicles can be modulated. However, we present the first data demonstrating that the amount of transmitter in a vesicle can regulate its volume. Amperometry and transmission electron microscopy have been used to determine that l-3,4-dihydroxyphenylalanine and reserpine increase and decrease, respectively, the volume of single pheochromocytoma cell vesicles as well as their catecholamine content. Because changes in vesicular catecholamine content are tracked by changes in vesicle volume, our results indicate that when quantal size is altered via the vesicular monoamine transporter the concentration of catecholamines within the vesicles remains relatively constant. This previously unidentified cellular response provides new insight into how catecholamines can be packaged in and released from secretory vesicles.
分泌囊泡的体积能够被调节,这一点已经得到了充分证实。然而,我们首次给出数据表明,囊泡中神经递质的量能够调节其体积。已使用安培测量法和透射电子显微镜来确定,L-3,4-二羟基苯丙氨酸和利血平分别增加和减少了单个嗜铬细胞瘤细胞囊泡的体积及其儿茶酚胺含量。由于囊泡体积的变化可追踪囊泡儿茶酚胺含量的变化,我们 的结果表明,当通过囊泡单胺转运体改变量子大小时,囊泡内儿茶酚胺的浓度保持相对恒定。这种先前未被识别的细胞反应为儿茶酚胺如何被包装进分泌囊泡以及如何从分泌囊泡中释放提供了新的见解。