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离体 (in vitro) 脊髓实验是脊髓电药理学的一种重要研究方法,与在体(in Vivo)实验比较,它具有许多特殊优点:(1) 可控制神经组织内部药物浓度,获得精确的量效关系;(2) 可人为地改变神经组织周围环境的温度、pH、离子组成等条件;(3) 电活动稳定;(4) 实验中不需麻醉;(5) 无血脑屏障;(6) 可联合开展药理、生理、生化等学科的研究。近二十年来,离体脊髓电药理学进展非常迅速,本文扼要介绍实验原理,并分析几种氨基酸、神经肽和药物对脊髓的作用机制。 相似文献
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离体(in vitro)脊髓实验是脊髓电药理学的一种重要研究方法,与在体(in vivo)实验比较,它具有许多特殊优点:(1)可控制神经组织内部药物浓度,获得精确的量效关系;(2)可人为地改变神经组织周围环境的温度、pH、离子组成等条件;(3)电活动稳定;(4)实验中不需麻醉;(5)无血脑屏障;(6)可联合开展药理、生理、生化等学科的研究。近二十年来,离体脊髓电药理学进展非常迅速,本文扼要介绍实验原理,并分析几种氨基酸、神经肽和药物对脊髓的作用机制。 相似文献
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渗透作用是植物水分代谢教学内容的一个难点,做好渗透作用演示实验是突破难点的重要教学手段。但是我感到,按照教材中渗透作用示意图来做这个实验,存在一些问题:(1) 用膀胱膜或肠衣作为半透膜,取材处理不太容易。(2) 长颈漏斗口的直径较大,半透膜受到蔗糖溶液的压力而下沉,影响液面高度的正常变化。(3) 实验装置比较大而沉重,不便于巡回演示。针对上述问题,采取了下面的措施。 相似文献
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《物理教师》2011年第1期文章《探究单摆测周期计时最佳位置》讨论了学生实验"探究单摆周期与摆长的关系"的周期计时最佳位置。笔者认为其方法有不妥当的地方:(1)对引起误差原因的理论分析有错误;(2)仅仅通过三组实验数据来讨论与偶然误差相关的规律问题不适当;(3)得出结论"不同的摆长最佳位置不一样"是错误的。 相似文献
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1 教学结构流程图 (见下页 )2 教学过程2 .1 课前准备1)了解学生的需要 ,引发学生的学习动机 ,使学生做好学习新知识的心理准备。前一次课末 ,教师印发问题征询表 ,学生预习、讨论、填表。征询内容血液是否解决预习前你想知道的问题预习后你还想知道的问题 2 )教师将收集到的问题进行分类整理为以下 3类 :第 1类 :与教学内容密切相关的 ,属于大纲要求的问题 (课堂上作为学习目标展示出来重点解决。若收集到的问题不能全面体现大纲的要求 ,教师应予以补充 ,以免影响知识的完整性 )。第 2类 :与教学内容有一定关联 ,但不属于大纲要求的… 相似文献
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网络化和信息化是现今大学物理实验教学改革的重要发展方向,而基于网络管理系统设计的大学物理实验不仅适应了开放式教学对教学管理的新需求,在改善实验教学中实验预习的薄弱环节也起着至关重要的作用。 相似文献
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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. 相似文献
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N. P. Vesselkin Yu. V. Natochin 《Journal of Evolutionary Biochemistry and Physiology》2010,46(6):592-603
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 相似文献
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