本文選題：壓力感受器 + 血壓��； 參考：《陜西師范大學》2010年博士論文

【摘要】： 壓力感受器如何感受血壓變化是感覺神經(jīng)生理學的一個重要問題。神經(jīng)生理學已經(jīng)建立壓力感受器通過調節(jié)動作電位頻率進而感受靜態(tài)和動態(tài)壓力的基本概念：神經(jīng)脈沖發(fā)放平均頻率編碼了外界刺激的強度,脈沖發(fā)放的頻率數(shù)正比于刺激的強度值。由于感受器神經(jīng)末梢的解剖結構非常微小,目前還不能直接通過實驗觀察其感受電位。隨著神經(jīng)科學、非線性科學、信息技術和計算機技術的交叉融合,已經(jīng)形成了以理論和實驗結合的神經(jīng)動力學研究方向。利用非線性動力學的概念,可以對生命中復雜的神經(jīng)放電模式、模式分岔(轉遷)規(guī)律進行研究,為認識復雜多變的神經(jīng)放電節(jié)律,揭示神經(jīng)動態(tài)放電和動態(tài)外界信息之間的關系,探討動態(tài)放電如何編碼動態(tài)外界信號的機制。 本文采用理論與實驗相結合的研究方法,研究主動脈弓壓力感受器編碼動脈血壓信號這個具體的編碼環(huán)節(jié)的生物物理機制和生理學意義。通過對家兔和大鼠動脈壓力感受器動態(tài)、靜態(tài)血壓變化作用下,神經(jīng)單纖維放電模式及其轉遷規(guī)律的研究。實驗發(fā)現(xiàn)了感受器的5種活動狀態(tài)：2類靜息(分別對應低壓閾值和高壓閾值)和3類放電行為。放電行為是由血壓變化過程中跨越兩個閾值產(chǎn)生的。對應動態(tài)血壓,跨越低壓閾值,感受器在收縮壓放電；跨越高壓閾值,感受器表現(xiàn)為在收縮壓放電的反常簇放電；位于兩個閾值之間,持續(xù)放電。對應靜壓力,跨越低壓閾值,感受器on-off放電；跨越高壓閾值,感受器on-off放電或整數(shù)倍放電；位于閾值之間,周期一放電并隨壓力增加頻率加快。實驗靜壓力下出現(xiàn)了on-off放電和整數(shù)倍放電等非周期放電模式,模型仿真了這類結果,提示它們分別對應跨越超臨界Hopf分岔和亞臨界Hopf分岔的動力學行為。神經(jīng)動力學的應用,為理解實驗現(xiàn)象的機理提供了有力的理論依據(jù)。 主要結果有 1.實驗獲得了隨動態(tài)平均血壓變化的感受器神經(jīng)單纖維的放電模式轉遷規(guī)律。隨著平均壓力升高,感受器神經(jīng)單纖維放電依次經(jīng)歷低壓靜息-收縮壓放電-連續(xù)放電-舒張壓放電的“反常簇放電”-高壓靜息。識別了感受器神經(jīng)單纖維的5種活動狀態(tài)：3種放電和2種靜息。在多例標本發(fā)現(xiàn)了新的“反常簇放電”現(xiàn)象,并認識到“反常簇放電”存在于高壓力區(qū)間,其機理是“去極化阻滯”。 2.實驗觀察了靜壓力下感受器神經(jīng)單纖維放電模式的轉遷規(guī)律。隨著靜壓力升高,感受器神經(jīng)單纖維放電依次經(jīng)歷了低壓靜息-on-off放電-持續(xù)周期一放電-on-off放電或者整數(shù)倍放電-高壓靜息。和動態(tài)平均血壓下的轉遷規(guī)律類似,感受器的2種靜息分別對應了低壓和高壓閾值。其中非周期的on-off放電和整數(shù)倍放電,提示在跨越閾值時,感受器放電遵循動力學的Hopf分岔機制。進而利用神經(jīng)動力學的分岔理論可以解釋感受器編碼血壓信號的機理。 3.構建了基于血壓壓力感受器感知血壓過程的生物寫實數(shù)學模型。該模型利用不同的函數(shù),對應血管區(qū)、感受器區(qū)和編碼區(qū),分別仿真了血管壁的機械形變、感受器局部電位產(chǎn)生和編碼區(qū)動作電位產(chǎn)生,進而構成完整的感受器數(shù)學模型。調節(jié)與實驗相一致的參數(shù)變化,研究了該數(shù)學模型在靜壓力和動態(tài)血壓變化下的放電模式及其轉遷規(guī)律。 4.數(shù)學模型仿真結果揭示了放電節(jié)律的轉遷規(guī)律的機制。隨著靜壓力的增加,確定性模型會表現(xiàn)出靜息、連續(xù)放電、靜息的轉遷歷程。考慮噪聲因素的作用,靜壓力增加時,放電節(jié)律會表現(xiàn)出靜息、on-off放電、連續(xù)均勻放電、整數(shù)倍放電、靜息的轉遷歷程,與實驗中靜壓力增加的現(xiàn)象一致。在動壓力作用下,隨著平均壓力的增加,放電會經(jīng)歷靜息、血壓峰值放電谷值不放電、連續(xù)放電、血壓峰值不放電血壓谷值放電、靜息的歷程,與實驗一致。 5.對數(shù)學模型進行分析,隨著靜壓力的增加,從靜息變到放電對應亞臨界Hopf分岔,從連續(xù)放電再到靜息是超臨界Hopf分岔。靜壓力下的on-off放電和整數(shù)倍放電是噪聲分別在超臨界和亞臨界Hopf點附件誘發(fā)的隨機節(jié)律。而“反常簇放電”是由于在動壓力作用下電活動行為因為血壓壓力在跨越Hopf分岔點引起的：血壓峰值處于靜息而血壓谷值時處于放電引起的。這就從理論上解釋了這些新節(jié)律的產(chǎn)生的動力學機制。。 上述結果表明,血壓信號的改變會引起感受器興奮性的變化,也就是去極化電流的動態(tài)變化。使得壓力感受器的放電節(jié)律在以去極化電流作為分岔參數(shù)的放電節(jié)律靜態(tài)分岔結構中,在平均血壓對應的位置附近按照血壓信號的時間歷程“動態(tài)游走”,形成動態(tài)放電節(jié)律；動態(tài)放電節(jié)律的時間歷程與血壓信號的時間動態(tài)歷程有較好的對應。利用非線性動力學分岔理論不僅從理論上揭示了血壓信號引起感受器神經(jīng)放電的機理,而且可以在包含放電頻率在內的多個層面上,在理論層次上建立動態(tài)血壓信號與相應動態(tài)放電之間的聯(lián)系,進一步認識了感受器的編碼機制。
[Abstract]:How bareporeceptor feelings of blood pressure change is an important problem in sensory neurophysiology. Neurophysiology has established the basic concept that bareporeceptor can feel static and dynamic pressure by regulating the frequency of action potential, which encodes the intensity of external stimuli, and the frequency of pulse distribution is proportional to the number of pulses. As the anatomical structure of the nerve endings of the receptor is very small, the sensory potential can not be observed directly by experiment. With the cross fusion of neuroscience, nonlinear science, information technology and computer technology, the research direction of the combination of theory and experiment has been formed. The concept of dynamics can be used to study the complex pattern of neural discharge and pattern bifurcation (transfer) in life, to understand the complex and changeable rhythms of neural discharge, to reveal the relationship between the dynamic discharge of the nerve and the dynamic external information, and to explore the mechanism of how dynamic discharge encodes the dynamic external signal.
This paper studies the biophysical and physiological significance of the specific coding link of aortic arch baroreceptor encoding arterial pressure signal by combining theoretical and experimental methods. Through the dynamic and static blood pressure changes in rabbit and rat arterial baroreceptor, the pattern of neural single fiber discharge and its transfer rules are used. The experiment found 5 active states of the receptor: 2 types of resting (corresponding to low pressure threshold and high pressure threshold respectively) and 3 types of discharge behavior. The discharge behavior is produced by two thresholds in the process of blood pressure change. It corresponds to the dynamic blood pressure, across the low pressure threshold, the receptor in the systolic pressure discharge, the threshold of the high pressure, the receptor performance. An anomalous cluster discharge in a systolic discharge; between two thresholds, continuous discharge. Corresponding static pressure, crossing low pressure threshold, receptor on-off discharge; crossing high pressure threshold, receptor on-off discharge or integer multiple discharge; between threshold, periodic discharge and increasing frequency with pressure force. Under experimental static pressure, on-off appears. The models of non periodic discharge, such as discharge and integer discharge, have simulated these results, suggesting that they correspond to the dynamic behavior of crossing over the supercritical Hopf bifurcation and subcritical Hopf bifurcation, and the application of neural dynamics provides a powerful theoretical basis for understanding the mechanism of the experimental phenomena.
The main results are
The 1. experiment obtained the change rule of the discharge mode of the sensory nerve single fiber with the dynamic mean blood pressure change. With the increase of the average pressure, the single fiber discharge of the receptor nerve underwent the "abnormal cluster discharge" - the high pressure resting with the low pressure resting - systolic pressure discharge - the continuous discharge diastolic discharge, and identified the 5 of the receptor nerve single fiber. Activity state: 3 kinds of discharge and 2 kinds of resting. A new phenomenon of "abnormal cluster discharge" is found in several specimens, and it is recognized that "abnormal cluster discharge" exists in the high pressure range, and its mechanism is depolarization block.
2. the transition law of the single fiber discharge mode of the receptor nerve under static pressure was observed under the static pressure. With the increase of static pressure, the single fiber discharge of the receptor nerve experienced the low pressure resting -on-off discharge - the continuous cycle one discharge -on-off discharge or the integer multiple discharge - the high pressure resting. The 2 kinds of resting rest respectively correspond to the low pressure and high pressure threshold, in which the non periodic on-off discharge and the integer multiple discharge indicate that the Hopf bifurcation mechanism of the receptor discharge follows the dynamics when the threshold is crossed. Then the mechanism of the blood pressure signal encoded by the receptor can be explained by the bifurcation theory of the neural dynamics.
3. a biorealistic mathematical model is constructed based on the blood pressure baroreceptor, which uses different functions, corresponding to the vascular area, the receptor area and the coding region, to simulate the mechanical deformation of the blood vessel wall, the local potential generation of the receptor and the generation of the action potential of the coded region, and then form a complete mathematical model of the receptor. Adjusting the parameter changes consistent with the experiment, we studied the discharge pattern and transition rule of the mathematical model under static pressure and dynamic blood pressure.
4. the simulation results of the mathematical model reveal the mechanism of the transition law of the discharge rhythm. With the increase of static pressure, the deterministic model will show resting, continuous discharge, and resting transition course. Considering the effect of the noise factors and the increase of the static pressure, the discharge rhythm will show resting, on-off discharge, continuous uniform discharge, integer discharge, resting. Under the action of dynamic pressure, with the increase of average pressure, the discharge will go through resting, the peak discharge valley of the blood pressure peak does not discharge, continuous discharge, the peak of blood pressure does not discharge the value of the blood pressure Valley, and the resting course is consistent with the experiment.
5. analysis of the mathematical model, with the increase of static pressure, from resting to discharge to subcritical Hopf bifurcation, from continuous discharge to rest to resting is a supercritical Hopf bifurcation. The on-off discharge and the integer multiple discharge under static pressure are random rhythms induced by the noise at supercritical and subcritical Hopf points respectively. The activity of electrical activity under the action of pressure is caused by the pressure of blood pressure across the Hopf bifurcation point: the peak of blood pressure is at the resting and the value of the blood pressure Valley at the discharge. This explains the kinetic mechanism of these new rhythms.
The above results show that the change of blood pressure signal causes the change in the excitatory of the receptor, that is the dynamic change of the depolarization current. It makes the discharge rhythm of the baroreceptor in the static bifurcation structure of the discharge rhythm with depolarization current as a bifurcation parameter, and the time course of the mean blood pressure near the corresponding position according to the blood pressure signal. "Dynamic walk" forms a dynamic discharge rhythm, and the time history of the dynamic discharge rhythm corresponds well with the time dynamic process of the blood pressure signal. The theory of nonlinear dynamics bifurcation not only reveals the mechanism of the nerve discharge caused by the blood pressure signal, but also can be in the multiple layers including the discharge frequency. On the theoretical level, the relationship between ambulatory blood pressure signals and corresponding dynamic discharges is established to further understand the coding mechanism of receptors.

【學位授予單位】：陜西師范大學
【學位級別】：博士
【學位授予年份】：2010
【分類號】：R35

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本文編號：1785961