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Title: 动作电位编码对神经细胞分泌的调控
Author: 段开来
Degree Level: 博士
Issued Date: 2003
Degree Grantor: 中国科学院中科院上海生命科学院神经科学研究所
Place of Degree Grantor: 中科院上海生命科学院神经科学研究所
Supervisor: 周专
Abstract: 动作电位是神经元的重要生理活动之一,它的主要生理功能之一是使神经元分泌神经递质,将信息传递到下一级细胞。不同神经元或同种神经元在不同状态下的动作电位发放都可以不同。人们已经用去极化方波等刺激对细胞的"刺激-分泌"拙联进行了大量的研究,并观察到突触前刺激模式的改变会引起突触后响应的不同。为了研究动作电位编码对分泌的影响,本学位论文用真实动作电位作为刺激模板,使得刺激方式进一步接近生理条件,并定义了4个参数n、m、f和d来描述动作电位的复杂发放模式F(n,m,f,d):设一串动作电位为"Burst",在单个Burst内的动作电位数目为"n",频率为"f",在一次刺激中的Burst数目为"m",两个相邻Burst之间的时间间隔为"d"。在大鼠的肾上腺嗜铬细胞和脊髓背根神经节(DRG)神经元上,我们用不同编码的动作电位刺激细胞,通过电容检测方法实时观察了动作电位编码变化对分泌的影响。我们的结果显示:(l)细胞分泌具有频率依赖性。对一定数目的动作电位,当动作电位频率较低时,分泌量会随着频率"f"的增加而增加。但当频率高于一定水平时(嗜铬细胞上,为"f"≥7Hz;DRG神经元上,为"f"≥10 Hz),进一步提高动作电位频率,分泌不再增加。(2)在高频动作电位刺激下,细胞分泌量与动作电位个数"n"成非线形关系。(3)当Burst间隔"d"大于1s时,"d"的变化对分泌量无影响。(4)当动作电位总数一定时,Burst个数即分组方式"m"对总分泌量影响比较大。将40个动作电位分作4组("m'=4)和并作一组("m"=1)刺激细胞,在嗜铬细胞上前者是后者分泌量的2.2±0.1倍,而在DRG神经元上后者是前者分泌量的1.5±0.2倍。我们的工作证明:除动作电位的频率和个数以外,编码参数"m"也能调控细胞分泌。在不同类型细胞上,编码参数对细胞分泌的调控可以不同。这可能与不同类型细胞在分泌动力学的差别有关。
English Abstract: Action potentials (APs) are the principal physiological stimuli for neurotransmitter secretion in neurons. One of its important functions is to trigger the secretion of the synapse. The AP firing is very complex. Most studies on stimulus-secretion coupling have been performed under voltage clamp using artificial electrical stimuli. And it is found that the change of presynaptic stimulus can result in difference of postsynaptic action. To investigate the modulatory effects of AP codes on neural secretion, we introduce a capacitance method to study AP-induced secretion in single cells. Real action potential was used as stimulus template. The action potential pattern was defined by a 4-parameter "code function"-F(n, m, f, d), where the four coding parameters (n, m, f, d) are defined as follows. A series of consecutive APs is defined as a "burst": "n" is the number of APs in a burst; "m" is the number of bursts in the whole AP pattern; "f is the frequency of APs in a burst; and "d" is the interval between two adjacent bursts (when m = 1, "d" has no meaning). With this method, cell secretion evoked by stimulation with an AP code was quantified in real time by membrane capacitance (C_m) in rat adrenal chromaffin cells (RACCs) and rat dorsal root ganglion (DRG) neurons. We found; 1. Our data confirmed that secretion increased when AP-frequency "f was increased. However, we found no further increase of secretion at higher frequencies (RACC, "f ≥ 7 Hz; DRG neuron, "f ≥ 10 Hz). 2. The relationship between secretion and AP numbers ("n") was not linear. 3. When "d" was longer than 1 second, the change of "d" had no effect on total secretion. 4. When the total number of APs and AP frequency were fixed, "m" can modulate secretion. The 4-burst AP-code evoked secretion 2.2±0.1 times greater than that caused by a single burst on RACCs, when total number of APs was 40. However on DRG neurons, a single burst evoked secretion 1.5±0.2 times greater than that caused by 4-burst AP-code. Our data indicated, besides "f' and "n", the physiological "m" effect may play a key role in AP-mediated neural information transfer within a single neuron and among the elements of a neural network. And this modulation has variety between different cells and tissues. This could be attributed to the multiformity of secretion kinetics.
Language: 中文
Content Type: 学位论文
URI: http://ir.sibs.ac.cn/handle/331001/2246
Appears in Collections:神经所(总)_学位论文

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Recommended Citation:
动作电位编码对神经细胞分泌的调控.段开来[d].中国科学院中科院上海生命科学院神经科学研究所,2003.20-25
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