Effect of hypoxic episode number and severity on ventilatory long-term facilitation in awake rats
Effect of hypoxic episode number and severity on ventilatory long-term facilitation in awake rats
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DOI：
10.1152/japplphysiol.00405.2002
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发表时间：
2002-12-01
影响因子：
3.3
通讯作者：
Ling, LM
中科院分区：
文献类型：
--
作者：
McGuire, M;Zhang, Y;Ling, LM
间歇性低氧诱导呼吸活动持续增强，称为长时程易化（LTF）。膈LTF在麻醉动物中饱和，使得额外的刺激事件不会导致LTF幅度的进一步增加。本研究验证了以下假设：1）清醒大鼠的催醒性LTF也饱和，2）更严重的缺氧和缺氧发作增加了诱导催醒性LTF的有效性。通过体积描记法测量清醒雄性Sprague-Dawley大鼠的分钟通气量。LTF由5次10%O-2低氧血症引起（幅度：高于基线17.3 +/- 2.8%，缺氧后15 - 45分钟，持续时间：45分钟），但不是12或8%O-2。10次、20次和72次12%O-2（分别为19.1 +/- 2.2、18.9 +/- 1.8和19.8 +/- 1.6%; 45、60和75分钟）也可诱发LTF，但3次或5次则不能诱发。这些结果表明，有一定范围的缺氧，诱导的deletatory LTF和额外的缺氧事件可能会增加持续时间，但不是这种反应的幅度。
Episodic hypoxia induces a persistent augmentation of respiratory activity, termed long-term facilitation (LTF). Phrenic LTF saturates in anesthetized animals such that additional episodes of stimulation cause no further increase in LTF magnitude. The present study tested the hypothesis that 1) ventilatory LTF also saturates in awake rats and 2) more severe hypoxia and hypoxic episodes increase the effectiveness of eliciting ventilatory LTF. Minute ventilation was measured in awake, male Sprague-Dawley rats by plethysmography. LTF was elicited by five episodes Of 10% O-2 poikilocapnic hypoxia (magnitude: 17.3 +/- 2.8% above baseline, between 15 and 45 min posthypoxia, duration: 45 min) but not 12 or 8% O-2. LTF was also elicited by 10, 20, and 72 episodes of 12% O-2 (19.1 +/- 2.2, 18.9 +/- 1.8, and 19.8 +/- 1.6%; 45, 60, and 75 min, respectively) but not by three or five episodes. These results show that there is a certain range of hypoxia that induces ventilatory LTF and that additional hypoxic episodes may increase the duration but not the magnitude of this response.