Rostrocaudal distribution of spinal respiratory motor activity in an in vitro neonatal rat preparation
Rostrocaudal distribution of spinal respiratory motor activity in an in vitro neonatal rat preparation
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DOI：
10.1016/j.neures.2004.07.011
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发表时间：
2004-11-01
影响因子：
2.9
通讯作者：
Iizuka, M
中科院分区：
文献类型：
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作者：
Iizuka, M
用新生大鼠离体脑干-脊髓-肋骨标本，研究了吸气和呼气活动在胸廓肌肉中的分布。呼气活动诱发灌注液pH值从7.4降低到7.1。所有第一至第十一肋间隙的肋间内肌（IIMs）均出现呼气爆发。虽然在更尾部的间隙中的IIMs表现出呼气爆发，只要低pH值的溶液存在于所有的制剂中，从IIMs在吻侧间隙中获得的呼气爆发逐渐消失，即使在低pH值的条件下，在约一半的制剂，这表明更多的尾部的IIMs发挥更大的作用，在呼气。在正常pH条件下，T1 VR-T11 VR检查的所有胸前根均表现出明显的吸气爆发，但T13 VR没有。低pH溶液在所有胸部VR中诱导额外的呼气爆发。呼气相绝对电压积分与吸气相绝对电压积分的比值从吻侧间隙到尾侧间隙逐渐显著增加。这些结果与以往哺乳动物体内实验结果雅阁。因此，脊髓呼吸运动输出中的吻尾梯度所需的神经元机制似乎在这种体外制备中得以保留。(C)2004年Elsevier爱尔兰有限公司和日本神经科学学会。All rights reserved.
The distribution of inspiratory and expiratory activities among rib-cage muscles was examined using isolated brainstem-spinal cord-rib preparations from neonatal rats. Expiratory activity was evoked by decreasing perfusate pH from 7.4 to 7.1. All internal intercostal muscles (IIMs) in the first to eleventh intercostal spaces showed expiratory bursts. Although the IIMs in the more caudal interspaces exhibited expiratory bursts for as long as the low pH solution was present in all preparations, the expiratory bursts obtained from the IIMs in the rostral interspaces gradually disappeared even under low pH conditions in about half the preparations, suggesting that the more caudal IIMs play the greater role in expiration. All thoracic ventral roots examined from T1VR-T11VR, but not T13VR, exhibited overt inspiratory bursts under normal pH conditions. Low pH solution induced additional expiratory bursts in all thoracic VRs. The ratio of the integral of the absolute electrical voltage during the expiratory phase to that during the inspiratory phase increased progressively and significantly from the rostral to the caudal interspaces. These results accord well with previous ones in mammals in vivo. Hence, the neuronal mechanisms necessary for a rostrocaudal gradient in spinal respiratory motor outputs seem to be preserved in this in vitro preparation. (C) 2004 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.