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研究发现副交感神经和交感神经同时控制心跳方式

2011/11/30 来源:搜狐
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来自英国布里斯托大学和澳大利亚墨尔本的弗洛里神经系统科学学院的研究小组,近日公开宣布他们发现了神经系统的一处区域是连接心脏和大脑的主要“角色”。

来自英国布里斯托大学和澳大利亚墨尔本的弗洛里神经系统科学学院的研究小组,近日公开宣布他们发现了神经系统的一处区域是连接心脏和大脑的主要“角色”。即当大脑的这部分区域出现了“工作故障”,那么人们因心脏疾病而死亡的风险就会提高。

据了解,神经系统的该区域具有十分重要的作用,该区域遭遇任何一种“小故障” 都会导致毁灭性的结果。科学家相信如果对它进行细节上的研究分析,那么一定会使得冠心病,心脏病以及其他一系列疾病的研究理论得到新的突破与发展。

为了清晰的观察到大脑如何对心脏进行“支配管理”,研究人员使用了若干先进的研究技术来研究这种大脑和心脏之间的神秘“连线者”。该研究报告的细节目前已出现在在线生理学医学期刊最新一期。

布里斯托大学的专家托尼·皮克林(Tony Pickering)和朱利安·佩顿(Julian Paton)教授与他们的同事罗宾·麦卡伦(Robin McAllen)共同合作负责该试验的研究。该具有创新性的合作让研究人员们创造出了一种分析和监视神经细胞的新方法,从而可以实现对心脏跳动及相关方面的过程的控制。

经研究发现,神经系统的副交感神经和交感神经部位会同时促成对心脏跳动方式的控制。副交感神经专门用来进行心血管的反射,其中包括当人处于压力下,让人的心脏放慢跳动。当副交感神经没有能力为心脏提供这种保护作用时,心力衰竭,高血压以及其他心血管疾病就会经常发生。

而且研究人员还在人类心脏中发现了这些副交感神经。研究人员也表示,他们最近也对一些限制进行了突破,对正在跳动心脏中的神经进行了观察。皮克林博士解释道,从实验中发现一系列心血管疾病中,例如心力衰竭导致的心脏病发作,高血压以及糖尿病 ,会产生一些不良预后,甚至会增加死亡的危险。

他们的研究结果说明对心脏神经节进行针对治疗,使副交感神经恢复工作,就可达到痊愈的效果。英国心脏基金会研究所的顾问海伦·威尔逊(Helene Wilson)表示,副交感神经对于调整心率十分重要。这样意味着,未来对心脏疾病的治疗将有新突破。

 

Processing of central and reflex vagal drives by rat cardiac ganglion neurones: an intracellular analysis

Robin M. McAllen, Lauren M. Salo, Julian F. R. Paton, Anthony E. Pickering

Non-technical summary  The brain controls the heart through parasympathetic (vagal) and sympathetic nerves. Vagal control is integral to cardiac health and a loss of vagal tone is a poor prognostic sign in cardiovascular diseases such as heart failure and hypertension. The vagal drive to the heart is transmitted across synapses located in the cardiac ganglia on the heart. We have developed a novel methodology to make intracellular recordings from cardiac ganglion neurones on the surface of the beating heart in a preparation with intact functional drive from the brainstem. We show how these neurones process their synaptic inputs and demonstrate that the ganglion plays a key role in regulating the level of vagal tone reaching the heart. This identifies the cardiac ganglion as a viable target for interventions to restore the transmission of vagal tone in cardiovascular diseases.

Abstract  Cardiac vagal tone is an important indicator of cardiovascular health, and its loss is an independent risk factor for arrhythmias and mortality. Several studies suggest that this loss of vagal tone can occur at the cardiac ganglion but the factors affecting ganglionic transmission in vivo are poorly understood. We have employed a novel approach allowing intracellular recordings from functionally connected cardiac vagal ganglion cells in the working heart–brainstem preparation. The atria were stabilised in situ preserving their central neural connections, and ganglion cells (n = 32) were impaled with sharp microelectrodes. Cardiac ganglion cells with vagal synaptic inputs (spontaneous, n = 10; or electrically evoked from the vagus, n = 3) were identified as principal neurones and showed tonic firing responses to current injected to their somata. Cells lacking vagal inputs (n = 19, presumed interneurones) were quiescent but showed phasic firing responses to depolarising current. In principal cells the ongoing action potentials and EPSPs exhibited respiratory modulation, with peak frequency in post-inspiration. Action potentials arose from unitary EPSPs and autocorrelation of those events showed that each ganglion cell received inputs from a single active preganglionic source. Peripheral chemoreceptor, arterial baroreceptor and diving response activation all evoked high frequency synaptic barrages in these cells, always from the same single preganglionic source. EPSP amplitudes showed frequency dependent depression, leading to more spike failures at shorter inter-event intervals. These findings indicate that rather than integrating convergent inputs, cardiac vagal postganglionic neurones gate preganglionic inputs, so regulating the proportion of central parasympathetic tone that is transmitted on to the heart.

文献链接:http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2011.214320/abstract

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