加拿大和美國科學(xué)家的一項(xiàng)研究,，闡述了蛋白質(zhì)ephrin如何控制神經(jīng)從脊髓到肢體肌肉的連接。相關(guān)論文發(fā)表在12月26日的《神經(jīng)元》（Neuron）上。
神經(jīng)系統(tǒng)是高精度且極其復(fù)雜的神經(jīng)網(wǎng)絡(luò)，主要功能是分析外界刺激并通過協(xié)調(diào)運(yùn)動對外界刺激進(jìn)行反應(yīng)。這一高精度來自神經(jīng)細(xì)胞和肌肉之間神經(jīng)連接的高準(zhǔn)確度。加拿大蒙特利爾臨床研究所(IRCM)神經(jīng)網(wǎng)絡(luò)發(fā)育研究部主任Artur Kania解釋說：“為了了解這是如何發(fā)生的,，我們研究了一個簡單的系統(tǒng)，在這個系統(tǒng)中,，神經(jīng)從脊髓延伸到肌肉,，不僅連接了如二頭肌這樣的屈肌，也連接了像三頭肌這樣的伸肌,。”之前的研究曾發(fā)現(xiàn),，出現(xiàn)在發(fā)育中的肢體內(nèi)的一種蛋白質(zhì)ephrin-A指引著連接伸肌的神經(jīng)指向特定的目標(biāo)。
研究人員用雞和小鼠胚胎作為模型,，發(fā)現(xiàn)了一個近親蛋白質(zhì)家族ephrin-B,，它指引神經(jīng)連接到拮抗肌群屈肌。這些研究共同構(gòu)成了一副完整圖像,，表述了肢體神經(jīng)如何準(zhǔn)確地將神經(jīng)系統(tǒng)與肌肉相連,。而且，通過研究相對簡單的神經(jīng)連接網(wǎng)絡(luò),，研究人員發(fā)現(xiàn)一個很可能在神經(jīng)系統(tǒng)中廣泛采用的分子策略,，這一分子策略將更復(fù)雜的神經(jīng)回路連接起來，學(xué)習(xí),、記憶和協(xié)調(diào)運(yùn)動需要的神經(jīng)回路就屬于這類更復(fù)雜的類型,。
神經(jīng)系統(tǒng)的錯誤連線被認(rèn)為是造成像癲癇和智力缺陷等的因素之一。通過研究肢體神經(jīng)發(fā)育的過程,，科學(xué)家能幫助發(fā)展新的療法來治療神經(jīng)系統(tǒng)受損的病人,。
加拿大健康研究所(CIHR)科學(xué)主管Rémi Quirion表示：“對ephrin蛋白質(zhì)的研究應(yīng)該有助于我們理解像孤獨(dú)癥和精神分裂癥這類疾病，以及很多神經(jīng)失調(diào)問題,。我們很驕傲能夠?yàn)檫@一研究提供支持,，并且希望這一研究能夠提高相關(guān)患者的生活質(zhì)量。”（生物谷Bioon.com）
生物谷推薦原始出處：
Neuron,26 December 2008 doi:10.1016/j.neuron.2008.11.011
Specification of Motor Axon Trajectory by Ephrin-B:EphB Signaling: Symmetrical Control of Axonal Patterning in the Developing Limb
Victor Luria1,6,Dayana Krawchuk9,Thomas M. Jessell2,3,4,6,Ed Laufer1,5,6,10,,andArtur Kania2,3,7,8,9,,
1 Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA
2 Department of Neuroscience, Columbia University Medical Center, New York, NY 10032, USA
3 Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032, USA
4 Howard Hughes Medical Institute, Columbia University Medical Center, New York, NY 10032, USA
5 Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
6 Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY 10032, USA
7 Faculty of Medicine, Université de Montréal, Montréal, QC, H3C 3J7, Canada
8 Department of Anatomy and Cell Biology and Division of Experimental Medicine, McGill University, Montréal, QC, H3A 2T5, Canada
9 Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, H2W 1R7, Canada
10 Present address: Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
Studies of the innervation of limb muscles by spinal motor neurons have helped to define mechanisms by which axons establish trajectories to their targets. Related motor axons select dorsal or ventral pathways at the base of the limb, raising the question of how these alternate trajectories are specified. EphA signaling has been proposed to control the dorsal trajectory of motor axons in conjunction with other signaling systems, although the respective contributions of each system to motor axon guidance are unclear. We show that the expression of EphB receptors by motor axons, and ephrin-B ligands by limb mesenchymal cells, directs the ventral trajectory of motor axons. Our findings reveal symmetry in the molecular strategies that establish this aspect of nerve-muscle connectivity. The involvement of ephrin:Eph signaling in guiding both sets of motor axons raises the possibility that other signaling systems function primarily to refine or modulate a core Eph signaling program.
