据美国媒体每日科学消息,这一研究能使我们更好地了解神经系统的发展及损害后神经细胞再生的过程。英国生物技术与生物科学研究理事会为此项研究投入了32万欧元的研究经费。
英国研究理事会成员、莱斯特大学细胞生理与药理学博士Volko Straub领导的这个研究项目也为一氧化氮为何在许多认知方面起如此重要作用给出了新的见解。Straub说:“一氧化氮气体具有两面性,一是它有较高毒性,对人体有害。但它也确实在大脑中自然地存在着,被神经细胞用来进行细胞间的交流。因此,一氧化氮即有毒性也可以用其有益一面作为信号传递。”
“在大脑发育过程中,一氧化氮对神经细胞的生长以及神经细胞间联系的形成有促进作用。认知对神经细胞间形成新的联系也有推动作用,许多情况下需要一氧化氮的帮助。”
尽管对一氧化氮在形成神经细胞连接的重要性有了认识,但科学家对其机制还了解不多。这项计划的目的是研究一氧化氮在神经细胞生长中的作用与神经细胞连接形成之间的关系。
Straub解释说:“在高等动物中研究这些作用和关系会因这些动物神经系统的复杂性而使研究面临困难。幸好进化为我们帮了忙,我们决定利用普通蜗牛的神经系统,它明显没有像高级动物,如小鼠那样复杂的神经系统。
“蜗牛的神经细胞相对较大而且好识别,易于操作。蜗牛的神经元被从神经系统中分离出来,并进行细胞培养,使其能生长和形成功能上的连接。对神经细胞生长和形成功能连接起作用的基本程序和因子在所有动物中都完好保留了下来。”
研究结果将会证明一氧化氮在神经细胞生长和形成功能连接上会发挥什么样的作用。从广泛意义上来说,研究结果将会加深对神经生长和形成功能连接的一些因素的了解。
部分英文原文:
Neural Modulation of Gut Motility by Myomodulin Peptides and Acetylcholine in the Snail Lymnaea
Families of peptide neuromodulators are believed to play important roles in neural networks that control behaviors. Here, we investigate the expression and role of one such group of modulators, the myomodulins, in the feeding system of Lymnaea stagnalis. Using a combination of in situ hybridization and antibody staining, expression of the myomodulin gene was confirmed in a number of identified behaviorally significant neuronal types, including the paired B2 motor neurons. The B2 cells were shown to project axons to the proesophagus, where they modulate foregut contractile activity. The presence of the five myomodulin peptide structures was confirmed in the B2 cells, the proesophagus, and the intervening nerve by mass spectrometry. Using a sensitive cell culture assay, evidence that the B2 cells are cholinergic also is presented. Application of four of the five myomodulin peptides to the isolated foregut increased both contraction frequency and tonus, whereas the main effect of acetylcholine (ACh) application was a large tonal contraction. The fifth myomodulin peptide (pQIPMLRLamide) appeared to have little or no effect on gut motility. Coapplication of all five myomodulin peptides gave a greater increase in tonus than that produced by the peptides applied individually, suggesting that corelease of the peptides onto the gut would produce an enhanced response. The combined effects that the myomodulin peptides and ACh have on foregut motility can mimic the main actions of B2 cell stimulation.