Dipartimento di Fisiologia Umana, Università degli Studi di Milano, via Mangiagalli 32, 20133 Milan, Italy.
Respir Physiol Neurobiol. 2010 Feb 28;170(2):141-9. doi: 10.1016/j.resp.2009.11.007. Epub 2009 Nov 20.
Diaphragmatic regions are recruited in a specialized manner either as part of a central motor program during non-respiratory maneuvers, e.g. vomiting, or because of reflex responses, e.g. esophageal distension. Some studies in cats and dogs suggest that crural and costal diaphragm may be differentially activated also in response to respiratory stimuli from chemoreceptors or lung and chest wall mechanoreceptors. To verify whether this could occur also in other species, the EMG activity from the sternal, costoventral, costodorsal, and crural diaphragm was recorded in 42 anesthetized rabbits in response to various respiratory maneuvers, such as chemical stimulation, mechanical loading, lung volume and postural changes before and after vagotomy, or a non-respiratory maneuver such as esophageal distension. Regional activity was evaluated from timing of the raw EMG signal, and amplitude and shape of the moving average EMG. In all animals esophageal distension caused greater inhibition of the crural than sternal and costal diaphragm, whereas under all the other conditions differential diaphragmatic activation never occurred. These results indicate that in response to respiratory stimuli the rabbit diaphragm behaves as a single unit under the command of the central respiratory control system.
膈区以特定的方式募集，要么作为非呼吸动作（例如呕吐）中的中枢运动程序的一部分，要么是因为反射反应，例如食管扩张。一些猫和狗的研究表明，在对来自化学感受器或肺和胸壁机械感受器的呼吸刺激的反应中，肋部和胸部膈肌也可能被不同程度地激活。为了验证这种情况是否也可能发生在其他物种中，我们在 42 只麻醉的兔子中记录了胸骨、肋腹、肋背和肋部膈肌的肌电图活动，以响应各种呼吸动作，如化学刺激、机械负荷、肺容积和迷走神经切断前后的姿势变化，或非呼吸动作，如食管扩张。通过原始肌电图信号的时间、移动平均肌电图的幅度和形状来评估区域活动。在所有动物中，食管扩张引起的肋部膈肌抑制大于胸骨和肋部膈肌，而在所有其他情况下，从未发生过膈肌的差异激活。这些结果表明，在呼吸刺激下，兔子的膈肌在中枢呼吸控制系统的命令下表现为一个单一的单位。
