人類的大腦就像是一個有機(jī)超級計(jì)算機(jī),，它能有條不紊井然有序迅速地解決從呼吸到猜謎等所有難題。近日科學(xué)家首次描述了神經(jīng)細(xì)胞是如何在瞬間管理其信號的傳輸過程,，該研究成果發(fā)表在最近出版的《科學(xué)》（Science）雜志上,。
神經(jīng)系統(tǒng)細(xì)胞使用多巴胺、血清素及去甲腎上腺素等小分子神經(jīng)遞質(zhì)進(jìn)行溝通,。多巴胺與諸如記憶等認(rèn)知功能相關(guān),，而血清素負(fù)責(zé)情緒控制，去甲腎上腺素則與注意力和覺醒有關(guān),。腦細(xì)胞通過神經(jīng)突觸傳遞化學(xué)遞質(zhì)構(gòu)成復(fù)雜的信息網(wǎng)絡(luò)系統(tǒng),。電信號可以使突觸小泡與膜融合，并將化學(xué)遞質(zhì)釋放,，這一過程以毫秒的速度發(fā)生,。
哥本哈根哥廷根大學(xué)和阿姆斯特丹大學(xué)的研究人員一直在研究參與膜融合的核心蛋白復(fù)合物（SNARE復(fù)合體），為大腦神經(jīng)的迅捷傳遞速度尋求解釋,。他們發(fā)現(xiàn),，突觸小泡含有不少于3份連接橋或“SNARE復(fù)合體”。囊泡只和一個SNARE復(fù)合體較長時間地與細(xì)胞膜融合,，慢慢地分泌神經(jīng)遞質(zhì),。SNARE復(fù)合體的前體在囊泡到達(dá)目標(biāo)膜之前出現(xiàn)。至少有三個SNARE復(fù)合體串聯(lián)時,，同步融合啟動,。如果小泡只有一個SNARE復(fù)合體,，就會長時間與目標(biāo)膜融合,。
哥本哈根大學(xué)神經(jīng)科學(xué)和藥理學(xué)系的索倫森表示，下一步他們將研究影響和調(diào)節(jié)SNARE復(fù)合體在小泡中數(shù)量的各種因素,，以確定是否與神經(jīng)細(xì)胞傳遞信息的快慢有關(guān),。且大腦一旦發(fā)生病變，是否會改變這種調(diào)節(jié)規(guī)律,。(生物谷Bioon.com)
生物谷推薦英文摘要：
Science DOI: 10.1126/science.1193134
Fast Vesicle Fusion in Living Cells Requires at Least Three SNARE Complexes
Ralf Mohrmann,1,2,* Heidi de Wit,3 Matthijs Verhage,3 Erwin Neher,1 Jakob B. S?rensen1,4,5,*
Exocytosis requires formation of SNARE complexes between vesicle- and target-membranes. Recent assessments in reduced model systems have produced divergent estimates of the number of SNARE complexes needed for fusion. Here, we used a titration approach to answer this question in intact, cultured chromaffin cells. Simultaneous expression of wild-type SNAP-25 and a mutant unable to support exocytosis progressively altered fusion kinetics and fusion pore opening, indicating that both proteins assemble into heteromeric fusion complexes. Expressing different wild-type:mutant ratios revealed a third power relationship for fast (synchronous) fusion and a near-linear relationship for overall release. Thus, fast fusion typically observed in synapses and neurosecretory cells requires at least three functional SNARE complexes, while slower release might occur with fewer. Heterogeneity in SNARE-complex number may explain heterogeneity in vesicular release probability.
1 Department of Membrane Biophysics, Max-Planck Institute for Biophysical Chemistry, G?ttingen, Germany.
2 Department of Physiology, University of Saarland, Homburg, Germany.
3 Center for Neurogenomics and Cognitive Research, Department of Functional Genomics, Vrije Universiteit Amsterdam and VU Medical Center, Amsterdam, Netherlands.
4 Department of Neuroscience and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
5 Lundbeck Foundation Center for Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark.
