Two vesicle pools for neurons

杨柳

KAVALALI/ELSEVIER5 l# j$ ~  V7 k( T/ H8 R

5 @5 M5 Y2 o$ a  gYildirim Sara, Ege Kavalali, and colleagues (University of Texas Southwestern Medical Center, Dallas, TX) show that nerve terminals possess two independent vesicle populations: one for activity-dependent neurotransmitter release, and one for spontaneous release.
( W  e6 h  V$ }. G2 t8 S! c- E2 V. \# ?2 a* K9 a( `
Activity-dependent release is the typical action potential–generating mechanism. But occasionally a vesicle leaks its contents without provocation. Most scientists figured these events〞which affect synaptic development and inhibit translation in dendrites〞reflect the occasional escape of a vesicle primed for activity-dependent release. But the new results reveal that spontaneously released vesicles comprise a pool of their own.
; w: P$ i6 q2 N! W' l/ e6 @
( p/ Z+ X. o7 L% o/ V/ a  \The two pools were distinguished by their filling mechanism: vesicles loaded with dyes by spontaneous endocytosis were then unloaded more rapidly by spontaneous release than by stimulated release. Activity-dependent endocytosis filled vesicles that were more rapidly unloaded by stimulated release. Blocking neurotransmitter refilling into vesicles at rest only affected spontaneous release, suggesting that the pools do not intermix.
* Q- r; b5 J3 p6 n4 Y6 O. M& W0 q3 S7 a
Spontaneous vesicles may be defective in fusion yet occasionally fuse where and when they should not. The two pools looked the same by EM and were similarly localized, so the differences probably lie in lipid or protein content. How the differences originate is unclear. "There could be two recycling pathways" such as local and endosomal routes, says Kavalali. "Or  might just be the use-dependent accumulation of defective vesicles over time."( S# m% Q1 f1 [- ~" x: o. P
& m; d* }3 Z- |: ~$ X: [
Reference:
# x8 v% t. z" Q; Q9 l, k* @, k! S7 m( t; W) P+ a
Sara, Y., et al. 2005. Neuron. 45:563–573.(Vesicles formed by spontaneous (left) or)

MIYAGI

干细胞研究还要面向临床

marysyq

有才的不在少数啊  

dypnr

谁都不容易啊 ~~  

我心飞翔

@,@..是什么意思呀？  

laoli1999

不看白不看，看也不白看  

nauticus

勤奋真能造就财富吗？  

科研人

先看看怎么样！  

剑啸寒

昨天没来看了 ～～  

nauticus

做对的事情比把事情做对重要。