突触可塑性与脑疾病的神经发育基础

大脑神经回路高度有序的神经元活动是高级脑功能的基础,神经元之间的突触联结是神经回路的关键功能节点。神经突触根据神经元活动调整其传递效能的能力,亦即突触可塑性,被认为是神经回路发育和学习与记忆功能的基础。其异常则可能导致如抑郁症和阿尔茨海默病等精神、神经疾病。将介绍这两种疾病与突触可塑性的关系,聚焦于相关分子和细胞机制以及新的研究、治疗手段等进展。     

刺激中缝背核区对猫小脑皮层浦肯野细胞电活动的影响

本文研究了刺激外周神经及中缝背核区对猫小脑皮层浦肯野细胞(Purkinje Cell,PC)电活动的影响。在清醒的去大脑猫上记录刺激桡深神经(NRP)及腓深神经(NPP)时PC的电变化,并观察刺激中缝背核区对PC自发放电以及肢体神经传入冲动诱发活动的影响。结果表明,刺激NPP和NRP均可引起小脑皮层第Ⅴ和第ⅦA小叶的PC产生兴奋或抑制反应。刺激中缝背核区对PC自发放电以及诱发活动主要起抑制性影响。     

家鸽峡核顶盖通路的神经传递

采用微量离子电泳的方法研究了家鸽峡核顶盖的神经传递。电刺激峡核小细胞部（Ｉｐｃ）主要诱发顶盖细胞的抑制性反应（Ｉ－型）,也有少量兴奋－抑制型反应（ＥＩ－型）,兴奋性反应以乙酰胆碱为递质,抑制性反应则以ＧＡＢＡ为递质。据推测,Ｉｐｃ可能通过直接的神经投射调制顶盖细胞的活动。     

鸣禽鸟发声行为的激素调节

讨论了性类固醇激素对鸣食发声行为及其神经回路的影响,从细胞回路水平,行为水平对性激素在幼年鸣食发声学习和成年鸣食鸣啭可塑性中的作用进行了全面论述,介绍了国内外在鸣禽发声这一研究领域的最新进展,对深入开展动物学习记忆神经机制的研究具有借鉴作用。     

人离体新皮层神经元的神经生物学特性

活检得到的人离体新皮层神经元的神经生物学研究表明,人新皮层神经元包括快锋电位和规则锋电位两种细胞类型,并存在局部抑制性突触环路和局部兴奋性突触环路,以兴奋性和抑制性氨基酸为重要的神经递质。另外,神经元的神经生物学特性还与胞外钙镁离子浓度有关。     

γ-氨基丁酸能神经投射对纹状体功能的调节作用

γ-氨基丁酸(γ-aminobutyric acid,GABA)是纹状体(striatum,Str)中重要的抑制性神经递质,介导了纹状体中绝大部分抑制性的神经传递。根据纹状体接收的GABA来源不同将其分为:来自苍白球(globus pallidus,GP)和黑质(substantia nigra,SN)的外源性GABA能神经投射,以及来自纹状体MSNs和中间神经元的内源性GABA能神经投射。GABA能抑制性投射通过影响纹状体的神经调控网络来调节和控制运动行为,多种运动功能障碍性疾病的发生都与纹状体的GABA能抑制性神经投射异常有关。现以GABA为切入点,对GABA能抑制性神经投射对纹状体功能的调节作用进行综述。     

刺激猫下丘脑LHA和VMN对小脑皮层神经元电活动的影响

在戊巴比妥钠麻醉的猫,电刺激下丘脑外侧区(LHA)和腹内侧核(VMN)可引起小脑皮层第Ⅵ和Ⅶ小叶浦肯野细胞和非浦肯野细胞抑制性、兴奋性和抑制-兴奋性的电活动,但以抑制性活动为主;这些反应的潜伏期多数为10-20ms,但也可长达90ms;一般刺激LHA比刺激VMN更有效。刺激下丘脑所激发的小脑神经元抑制性电活动可为静脉注射组胺H_1受体阻断剂扑尔敏所阻断。本文对上述观察的可能作用作了讨论。     

自闭症谱系障碍的分子遗传学研究进展

自闭症谱系障碍(Autism spectrum disorder, ASD)是一类常见神经发育疾病,以社会交往障碍、刻板重复行为与狭隘的兴趣为主要临床特征。在过去40年间,ASD患病率呈不断上升趋势,因而日益受到人们关注。近年来由于大规模外显子测序的应用,发现了许多新的ASD易感基因。这些易感基因富集在几个共同的遗传信号通路中,参与突触形成和染色质重构等。最新的动物模型研究表明,ASD的发病机制包括神经突触可塑性异常和神经回路兴奋性-抑制性平衡紊乱。本文从ASD遗传病因的高度异质性、众多致病基因突变影响的共同生物学过程以及遗传诊断方法和药物研发的进展等几个方面进行了综述,以期帮助人们深入了解ASD的遗传基础和转化研究现状。     

γ-氨基丁酸(GABA)转运蛋白的结构、功能和调控

神经信号的有效传递有赖于对神经递质的精确调节,转运蛋白在其中起看决定性的作用。作为哺乳动物中枢神经系统中最主要的抑制性系统,GABA能系统在生物体内参与多种神经生理活动,自90年代初首次克隆了GABA转运蛋白基因以来,对它的研究也越来越深入和越来越多,本对GABA转运蛋白的结构功能和调控仅作了简要综述。     

神经胶质细胞的生理

神经胶质细胞(NG)的总体积占脑的一半,数量远远超过神经元。NG膜电位大于神经元的膜电位,且完全决定于[K~ ]_0。NG 不产生动作电位。神经元与 NG 之间为细胞外间隙。神经元活动时(不论是兴奋性或抑制性神经元)有 K~ 释放至细胞外间隙,引起 NG 去极化。NG 去极化值的大小反映神经元活动的数量及频率。NG 可以限制 K~ 的扩散,故 NG 虽不影响神经的传导,却可影响其后电位。尚有一些令人感兴趣的问题,有待进一步澄清或深入。例如:[K~ ]_0的改变是否引起 NG 的代谢反应、NG 对递质的浓度有无影响及能否调节、以及 NG 与癫痫发作有何关系等等。     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Principles of organization and evolution of systems of regulation of functions

Evolution of living organisms is closely connected with evolution of structure of the system of regulations and its mechanisms. The functional ground of regulations is chemical signalization. As early as in unicellular organisms there is a set of signal mechanisms providing their life activity and orientation in space and time. Subsequent evolution of ways of chemical signalization followed the way of development of delivery pathways of chemical signal and development of mechanisms of its regulation. The mechanism of chemical regulation of the signal interaction is discussed by the example of the specialized system of transduction of signal from neuron to neuron, of effect of hormone on the epithelial cell and modulation of this effect. These mechanisms are considered as the most important ways of the fine and precise adaptation of chemical signalization underlying functioning of physiological systems and organs of the living organism