Respiratory activity in the facial nucleus in an in vitro brainstem of tadpole, Rana catesbeiana.
Respiratory activity in the facial nucleus in an in vitro brainstem of tadpole, Rana catesbeiana.
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蝌蚪体外脑干面核的呼吸活动。
DOI：
10.1113/jphysiol.1996.sp021327
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Pack,AI
中科院分区：
文献类型：
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作者：
LiaoG-S;Kubin,L;Galante,RJ;Fishman,AP;Pack,AI
1. 在呼吸中枢神经控制的研究中，比较方法的优势很少。我们开发了一种体外脑干制剂，利用鲶鱼幼虫产生两种具有肺和鳃通气特征的节律性神经活动。基于面部（VII）神经活动的模式，肺和鳃节律相关的呼吸周期被分为三个不同的阶段。本研究的目的是表征和分类呼吸运动神经元在发育中期（XII - XVII）的膜电位轨迹。2. 在面部运动核区域的细胞内记录了75个呼吸调节神经元。静息膜电位在- 40 ~ - 80 mV之间。其中60个被鉴定为VII运动神经元，15个是非反激激活的。在75个神经元中，56个神经元的膜电位受到肺节律（5 ~ 27 mV）和鳃节律（3 ~ 15 mV）的调节，其余19个神经元仅受到肺节律（6 ~ 23 mV）的调节。未观察到单独有鳃调节的细胞。3. 所有受肺节律性调节的细胞只有相结合的去极化或超极化膜电位波动，可分为四种不同的模式。相反，在56个受鳃节律性调节的细胞中，32个在鳃周期的不同阶段（区分出四种模式）发生阶段性去极化，而其余24个则以两种不同的模式进行阶段跨越。在受两种节律调节的细胞中，肺和鳃的调节幅度成比例相关。4. 在所研究的所有16个神经元中，观察到在负电流或氯离子（Cl‐）注射后，在肺或鳃呼吸周期的一部分中，相位抑制输入减少或逆转。在6个神经元中分析了与鳃节律相关的相位膜阻力调节，在超极化期间检测到体细胞膜阻力（0.7‐8.1 M ω）的相对降低。5. 我们认为，在这些发育的中间阶段：(a)运动神经元中的鳃和肺呼吸振荡都是由呼吸前运动神经元产生的，只有少数不同的活动模式；(b)这些模式描绘了中枢产生的呼吸周期的不同部分；(c)由Cl‐介导的阶段性突触抑制有助于形成呼吸运动神经元的膜电位轨迹。
1. In studies of the central neural control of breathing, little advantage has been taken of comparative approaches. We have developed an in vitro brainstem preparation using larval Rana catesbeiana which generates two rhythmic neural activities characteristic of lung and gill ventilation. Based on the pattern of the facial (VII) nerve activity both lung and gill rhythm‐related respiratory cycles were divided into three distinct phases. The purpose of this study was to characterize and classify membrane potential trajectories of respiratory motoneurons in the VII nucleus at intermediate stages (XII‐XVII) of development. 2. Seventy‐five respiratory‐modulated neurons were recorded intracellularly within the facial motor nucleus region. Their resting membrane potential was between ‐40 and ‐80 mV. Sixty of them were identified as VII motoneurons and fifteen were non‐antidromically activated. Membrane potentials of fifty‐six of the seventy‐five neurons were modulated with both lung (5‐27 mV) and gill rhythms (3‐15 mV) and the remaining nineteen neurons had only a modulation with lung rhythmicity (6‐23 mV). No cells with gill modulation alone were observed. 3. All of the cells modulated with lung rhythmicity had only phase‐bound depolarizing or hyperpolarizing membrane potential swings which could be categorized into four distinct patterns. In contrast, of the fifty‐six cells modulated with gill rhythmicity, thirty‐two were phasically depolarized during distinct phases of the gill cycle (four patterns were distinguished), whereas the remaining twenty‐four were phase spanning with two distinct patterns. The magnitudes of lung and gill modulations were proportionally related to each other in the cells modulated with both rhythms. 4. In all sixteen neurons studied, a reduction or a reversal of phasic inhibitory inputs during a portion of the lung or gill respiratory cycle was observed following a negative current or chloride ion (Cl‐) injection. The phasic membrane resistance modulation in relation to the gill rhythm was analysed in six neurons and a relative decrease in the somatic membrane resistance (0.7‐8.1 M omega) was detected during the periods of hyperpolarization. 5. We propose that, at these intermediate stages of development: (a) both gill and lung respiratory oscillations in motoneurons are generated by respiratory premotor neurons having only a few distinct activity patterns; (b) these patterns delineate distinct portions of the centrally generated respiratory cycles; and (c) phasic synaptic inhibition, mediated by Cl‐, contributes to shaping the membrane potential trajectories of respiratory motoneurons.