Transient configurations of baroresponsive respiratory-related brainstem neuronal assemblies in the cat
Transient configurations of baroresponsive respiratory-related brainstem neuronal assemblies in the cat
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DOI：
10.1111/j.1469-7793.2000.t01-1-00509.x
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发表时间：
2000-06-01
影响因子：
5.5
通讯作者：
Shannon, R
中科院分区：
文献类型：
--
作者：
Arata, A;Hernandez, YM;Shannon, R
1.气体交换的调节需要呼吸系统和心血管系统的协调。以前的工作表明，延髓中缝神经元在腹侧呼吸群中从压力感受器向神经元转换和传递信息。这项研究验证了分布的脑干神经元组件在呼吸周期和压力感受器刺激期间瞬时重新配置的假设。静脉注射α(1)-肾上腺素能受体激动剂、一侧颈动脉窦压力改变或阻断降主动脉对14只乌拉坦麻醉、迷走神经切断、瘫痪、人工呼吸猫的血压产生扰动。用微电极阵列同时监测以下两个或两个以上部位的神经元：中缝隐核、中缝大核、延髓吻侧和尾侧腹外侧部以及孤束核。用关节周触发直方图、重力表示法和相关模式检测方法检测压力反应组件的瞬时构型。数据还用周期触发直方图、刺激前时间和累积和直方图、交叉相关图、峰触发的传出膈神经活动平均值和联合脉冲构型散点图(雪花)进行分析。将来自对照呼气相的5至9个同时记录的尖峰波序列与来自对照吸气相的交错等持续时间段的数据进行比较。在7只动物中，重力分析检测到的显著脉冲同步性仅限于呼吸周期的一个阶段。分布同步的重复模式被检测到，局限于压力感受器活动改变的时期，涉及在刺激期间单独不改变放电率的神经元。雪花和逻辑互相关分析为脉冲在并行活动的平行通道中的协同作用提供了证据。在至少有一个压力反应细胞的17对神经元中，有12对神经元的联合周期触发直方图检测到了指示共享输入或功能性兴奋性相互作用的同步性，这些共同输入或功能性兴奋性相互作用随着呼吸周期中的时间变化而变化。其中四对神经元对各自的放电率没有呼吸调节。来自其他八对的数据表明，在呼吸周期期间，抑制作用出现波动。结果表明，在呼吸周期中，压力感应性神经元组件的重复瞬间配置，没有伴随的组成神经元的放电率变化，并提示了压力感受器介导的反射的分布式网络机制。
1. The regulation of gas exchange requires coordination of the respiratory and cardiovascular systems. Previous work suggested that medullary raphe neurones transform and transmit information from baroreceptors to neurones in the ventral respiratory group. This study tested the hypothesis that distributed brainstem neuronal assemblies are transiently reconfigured during the respiratory cycle and baroreceptor stimulation.2. Blood pressure was perturbed by intravenous injection of an alpha(1)-adrenergic receptor agonist, unilateral pressure changes in the carotid sinus, or occlusion of the descending aorta in 14 Did-urethane anaesthetized, vagotomized, paralysed, artificially ventilated cats. Neurones were monitored simultaneously with microelectrode arrays in two or more of the following sites: n. raphe obscurus, n. raphe magnus, rostral and caudal ventrolateral medulla, and the nucleus tractus solitarii.3. Transient configurations of baroresponsive assemblies were detected with joint pericycle-triggered histograms, the gravitational representation, and related pattern detection methods. Data were also analysed with cycle-triggered histograms, peristimulus-time and cumulative sum histograms, cross-correlograms, spike-triggered averages of efferent phrenic activity, and joint impulse configuration scatter diagrams (snowflakes).4. Five to nine simultaneously recorded spike trains from control expiratory phases were compared with data from interleaved equal-duration time blocks from control inspiratory phases. In each of seven animals, significant impulse synchrony detected by gravity analysis was confined to one phase of the respiratory cycle.5. Repeated patterns of distributed synchrony confined to periods of altered baroreceptor activity were detected and involved neurones that individually did not change firing rates during stimulation. Snowflakes and logical cross-correlation analysis provided evidence for the cooperative actions of impulses in concurrently active parallel channels.6. In 12 of 17 pairs of neurones with at least one baroresponsive cell, joint pericycle-triggered histograms detected synchrony indicative of shared inputs or functional excitatory interactions that varied as a function of time in the respiratory cycle. Neurones in four of the pairs had no respiratory modulation of their individual firing rates. Data from eight other pairs were indicative of fluctuations in inhibition during the respiratory cycle.7. The results demonstrate repeated transient configurations of baroresponsive neuronal assemblies during the respiratory cycle, without concomitant firing rate changes in the constituent neurones, and suggest distributed network mechanisms for the modulation of baroreceptor-mediated reflexes.