Hendricks J C, Petrof B J, Panckeri K, Pack A I
Department of Clinical Studies, School of Veterinary Medicine, Hospital of the University of Pennsylvania, Philadelphia 19104-6010.
Am Rev Respir Dis. 1993 Jul;148(1):185-94. doi: 10.1164/ajrccm/148.1.185.
Sleep-disordered breathing (SDB) is seen during rapid eye movement (REM) sleep in English bulldogs, but it is absent during non-REM sleep. The SDB during REM sleep is associated with changes in neural drive to the diaphragm (DIA) and to an upper airway dilator, the sternohyoid (SH). In the present study, the EMG activity of the DIA was recorded in unrestrained, naturally sleeping, English bulldogs (n = 6) and in control dogs (n = 5). The EMG of the SH was recorded in five of these bulldogs and in four of the control dogs. The activity of the DIA was similar in the two groups of dogs throughout sleep, with the normal increased variability and altered recruitment patterns during REM sleep in all dogs. However, in the presence of the narrowed upper airway of bulldogs, the pattern of the upper airway dilator was dramatically different. In bulldogs, SH activity was virtually always related to inspiration (96 to 100% of breaths during both waking and non-REM sleep). In contrast, SH activity showed inspiratory-related increases in only a minority of breaths during non-REM sleep (32%) in control dogs (p < 0.05). Furthermore, SH drive, as measured by the plateau amplitude, fell during REM sleep in bulldogs, whereas it increased in control dogs (p < 0.05). In control dogs without SDB, we found that central respiratory drive to the SH was highest but variable during waking and minimal during non-REM sleep and that it fluctuated with phasic events during REM sleep. In bulldogs, however, high levels of SH activity occurred during waking and throughout non-REM sleep, apparently preventing SDB in these states. Episodic decreases in SH drive were observed during REM, and they were associated with SDB. These data support the proposition that compensatory pharyngeal dilator hyperactivity is necessary to maintain airway patency and normal breathing in bulldogs, a canine breed with an anatomically compromised upper airway.
在英国斗牛犬的快速眼动（REM）睡眠期间会出现睡眠呼吸障碍（SDB），但在非快速眼动睡眠期间则不存在。REM睡眠期间的SDB与支配膈肌（DIA）和上气道扩张肌胸骨舌骨肌（SH）的神经驱动变化有关。在本研究中，记录了6只自由活动、自然睡眠的英国斗牛犬和5只对照犬的膈肌肌电图（EMG）活动。在其中5只斗牛犬和4只对照犬中记录了胸骨舌骨肌的EMG。两组犬在整个睡眠过程中膈肌的活动相似，所有犬在REM睡眠期间均出现正常的变异性增加和募集模式改变。然而，在斗牛犬上气道变窄的情况下，上气道扩张肌的模式有显著差异。在斗牛犬中，胸骨舌骨肌的活动几乎总是与吸气相关（清醒和非REM睡眠期间96%至100%的呼吸）。相比之下，对照犬在非REM睡眠期间只有少数呼吸（32%）的胸骨舌骨肌活动显示与吸气相关的增加（p<0.05）。此外，通过平台期振幅测量，斗牛犬在REM睡眠期间胸骨舌骨肌的驱动下降，而对照犬则增加（p<0.05）。在没有SDB的对照犬中，我们发现支配胸骨舌骨肌的中枢呼吸驱动在清醒时最高但变化不定，在非REM睡眠时最小，并且在REM睡眠期间随相位事件波动。然而，在斗牛犬中，清醒和整个非REM睡眠期间均出现高水平的胸骨舌骨肌活动，显然在这些状态下可预防SDB。在REM期间观察到胸骨舌骨肌驱动的间歇性下降，且与SDB相关。这些数据支持这样的观点，即对于英国斗牛犬这种上气道解剖结构受损的犬种，代偿性咽部扩张肌活动亢进对于维持气道通畅和正常呼吸是必要的。
