加拿大和美國科學家的一項研究，闡述了蛋白質ephrin如何控制神經從脊髓到肢體肌肉的連接,。相關論文發(fā)表在12月26日的《神經元》（Neuron）上。
神經系統(tǒng)是高精度且極其復雜的神經網絡,，主要功能是分析外界刺激并通過協調運動對外界刺激進行反應,。這一高精度來自神經細胞和肌肉之間神經連接的高準確度,。加拿大蒙特利爾臨床研究所(IRCM)神經網絡發(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，出現在發(fā)育中的肢體內的一種蛋白質ephrin-A指引著連接伸肌的神經指向特定的目標,。
研究人員用雞和小鼠胚胎作為模型,，發(fā)現了一個近親蛋白質家族ephrin-B，它指引神經連接到拮抗肌群屈肌,。這些研究共同構成了一副完整圖像,，表述了肢體神經如何準確地將神經系統(tǒng)與肌肉相連。而且,，通過研究相對簡單的神經連接網絡，研究人員發(fā)現一個很可能在神經系統(tǒng)中廣泛采用的分子策略,，這一分子策略將更復雜的神經回路連接起來,，學習、記憶和協調運動需要的神經回路就屬于這類更復雜的類型,。
神經系統(tǒng)的錯誤連線被認為是造成像癲癇和智力缺陷等的因素之一,。通過研究肢體神經發(fā)育的過程，科學家能幫助發(fā)展新的療法來治療神經系統(tǒng)受損的病人,。
加拿大健康研究所(CIHR)科學主管Rémi Quirion表示：“對ephrin蛋白質的研究應該有助于我們理解像孤獨癥和精神分裂癥這類疾病,，以及很多神經失調問題。我們很驕傲能夠為這一研究提供支持,，并且希望這一研究能夠提高相關患者的生活質量,。”（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.
