Functional associations among simultaneously monitored lateral medullary respiratory neurons in the cat. I. Evidence for excitatory and inhibitory actions of inspiratory neurons.
Functional associations among simultaneously monitored lateral medullary respiratory neurons in the cat. I. Evidence for excitatory and inhibitory actions of inspiratory neurons.
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同时监测的猫侧髓呼吸神经元之间的功能关联。
DOI：
10.1152/jn.1987.57.4.1078
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发表时间：
1987
影响因子：
2.5
通讯作者：
Lindsey,BG
中科院分区：
文献类型：
--
作者：
Segers,LS;Shannon,R;Saporta,S;Lindsey,BG
数据来自 45 只麻醉 (Dial)、瘫痪、人工通气、双侧迷走神经切断的猫。细胞外电极阵列用于同时监测位于腹侧呼吸组头侧和尾侧区域的侧髓呼吸神经元的活动。确定每个神经元和并发膈神经活动的平均放电率作为呼吸周期中时间的函数。使用逆向刺激技术测试大多数细胞向脊髓或同侧迷走神经的轴突投射。通过同时记录的尖峰序列的互相关分析了 761 对同侧呼吸神经元，其中至少有一个神经元的最大放电率发生在吸气相。 410 对吸气 (I) 神经元中有 23% 显示出短时间尺度相关性，表明由于突触连接或共享输入而存在功能关联。由 I 细胞和呼气 (E) 神经元组成的 351 对神经元中，有 8% 是相关的。我们发现了球脊髓 I 神经元和 I 细胞兴奋的证据，而 NAA I 细胞刺激脊髓和迷走神经（NAA 神经元）不会逆向激活这些神经元和 I 细胞。我们还获得了表明最大放电率发生在 I 期前半部分的细胞（I-DEC 神经元）的抑制作用的数据。这些作用包括抑制其他 I-DEC 神经元、抑制最大放电率发生在 I 期后半部分的细胞（I-AUG 神经元）、抑制 E-DEC 神经元和抑制 E-AUG 细胞。百分之六十二 (31/50) 的相关性可以解释为兴奋性或抑制性少突触连接的证据，是在由尾侧和喙侧腹侧呼吸组神经元组成的对中检测到的。 88% (14/16) 提出的组间兴奋性连接涉及从该对的喙部神经元到尾部细胞的投射，而 73% (11/15) 提出的抑制性连接涉及尾部到喙部的投射。这些结果支持并提出了几种可能有助于控制呼吸周期各阶段增强活动的发展和时间安排的机制假设。
Data were obtained from 45 anesthetized (Dial), paralyzed, artificially ventilated, bilaterally vagotomized cats. Arrays of extracellular electrodes were used to monitor simultaneously the activities of lateral medullary respiratory neurons located in the rostral and caudal regions of the ventral respiratory group. The average discharge rate as a function of time in the respiratory cycle was determined for each neuron and concurrent phrenic nerve activity. Most cells were tested for axonal projections to the spinal cord or the ipsilateral vagus nerve using antidromic stimulation techniques. Seven hundred and sixty-one pairs of ipsilateral respiratory neurons that contained at least one neuron whose maximum discharge rate occurred during the inspiratory phase were analyzed by cross-correlation of the simultaneously recorded spike trains. Twenty-three percent of the 410 pairs of inspiratory (I) neurons showed short time scale correlations indicative of functional association due to paucisynaptic connections or shared inputs. Eight per cent of the 351 pairs composed of an I cell and and expiratory (E) neuron were correlated. We found evidence for excitation of both bulbospinal I neurons and I cells that were not antidromically activated by stimulation of the spinal cord and vagus nerve (NAA neurons) by NAA I cells. We also obtained data suggesting inhibitory actions of cells whose maximum discharge rate occurred in the first half of the I phase (I-DEC neurons). These actions included inhibition of other I-DEC neurons, inhibition of cells whose greatest firing rate occurred in the last half of the I phase (I-AUG neurons), inhibition of E-DEC neurons, and inhibition of E-AUG cells. Sixty-two percent (31/50) of the correlations that could be interpreted as evidence for an excitatory or inhibitory paucisynaptic connection were detected in pairs composed of a caudal and a rostral ventral respiratory group neuron. Eighty-eight percent (14/16) of proposed intergroup excitatory connections involved a projection from the rostral neuron of the pair to the caudal cell, whereas 73% (11/15) of proposed inhibitory connections involved a caudal-to-rostral projection. These results support and suggest several hypotheses for mechanisms that may help to control the development of augmenting activity in and the timing of each phase of the respiratory cycle.