Sympathoexcitatory response to peripheral chemoreflex activation is enhanced in juvenile rats exposed to chronic intermittent hypoxia
Sympathoexcitatory response to peripheral chemoreflex activation is enhanced in juvenile rats exposed to chronic intermittent hypoxia
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DOI：
10.1113/expphysiol.2006.034868
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发表时间：
2006-11-01
影响因子：
2.7
通讯作者：
Machado, Benedito H.
中科院分区：
文献类型：
--
作者：
Braga, Valdir A.;Soriano, Renato N.;Machado, Benedito H.
在本研究中，我们测试的假设，慢性间歇性缺氧（CIH）产生的变化，自主神经和呼吸反应急性外周化学反射激活。为了达到这一目标，3周龄大鼠暴露于CIH 10天（6%O-2持续40 s，间隔9 min; 8 h/天（-1））。然后将它们用于获得工作的心-脑干制备物，并且使用该未麻醉的实验制备物，用氰化钾（0.05%，通过灌注系统注射）激活化学反射，并记录胸交感神经活动（tSNA）、心率和膈神经放电（PND）。当与对照动物（n = 12）相比时，经历CIH的大鼠（n = 12）呈现以下响应于化学反射激活的显著变化：（78 +/- 4对比48 +/- 3%）;（B）在20 ° C下PND频率的持久增加（0.52 +/- 0.03与0.36 +/- 0.03 Hz）和30 s（0.40 +/- 0.02 vs 0.31 +/- 0.02 Hz）;（c）心动过缓反应更强（-218 +/- 20 vs-163 +/- 16次/min（-1））。这些结果表明，自主神经和呼吸反应的化学反射激活的幼年大鼠先前提交CIH大大增加。
In the present study, we tested the hypothesis that chronic intermittent hypoxia (CIH) produces changes in the autonomic and respiratory responses to acute peripheral chemoreflex activation. To attain this goal, 3-week-old rats were exposed to 10 days of CIH (6% O-2 for 40 s at 9 min intervals; 8 h day(-1)). They were then used to obtain a working heart-brainstem preparation and, using this unanaesthetized experimental preparation, the chemoreflex was activated with potassium cyanide (0.05%, injected via the perfusion system), and the thoracic sympathetic nerve activity (tSNA), heart rate and phrenic nerve discharge (PND) were recorded. Rats subjected to CIH (n = 12), when compared with control animals (n = 12), presented the following significant changes in response to chemoreflex activation: (a) an increase in tSNA (78 +/- 4 versus 48 +/- 3%); (b) a long-lasting increase in the frequency of the PND at 20 (0.52 +/- 0.03 versus 0.36 +/- 0.03 Hz) and 30 s (0.40 +/- 0.02 versus 0.31 +/- 0.02 Hz) after the stimulus; and (c) a greater bradycardic response (-218 +/- 20 versus -163 +/- 16 beats min(-1)). These results indicate that the autonomic and respiratory responses to chemoreflex activation in juvenile rats previously submitted to CIH are greatly increased.