Ainsworth D M, Eicker S W, Nalevanko M E, Ducharme N G, Hackett R P, Snedden K
Department of Clinical Sciences College of Veterinary Medicine, Cornell University, Ithaca, NY 14850, USA.
Respir Physiol. 1996 Oct;106(1):35-46. doi: 10.1016/0034-5687(96)00058-8.
Horses chronically-instrumented with costal diaphragmatic electromyographic electrodes were studied during exercise while unencumbered by a breathing mask. Exercise-associated changes in esophageal (Pes), gastric (Pga) and transdiaphragmatic (Pdi) pressures were measured and related to diaphragmatic electromyographic activity (CS EMG) and to left forelimb impact. In all breaths examined, CS EMG always coincided with decrements in Pes. For all exercise trials, linear increases in CS EMG, Pga and Pdi and linear decreases in Pes, as a function of exercise intensity, always occurred. During all gaits, breathing frequency (fR) was entrained with stride frequency (fS) one for one. However, a constant phase-coupling relationship between fR and fS, observed when horses cantered and galloped, was absent when horses walked or trotted. We conclude that biomechanical forces contribute minimally to ventilation in exercising horses, that the diaphragm is always phasically active during each breath and its total electrical activity and mechanical output are proportional to the exercise hyperpnea.
对长期植入肋膈肌肌电图电极的马匹在运动过程中进行了研究，此时马匹未佩戴呼吸面罩。测量了运动相关的食管压力（Pes）、胃内压力（Pga）和跨膈压力（Pdi）变化，并将其与膈肌肌电图活动（CS EMG）以及左前肢冲击相关联。在所有检查的呼吸中，CS EMG总是与Pes的下降同时出现。对于所有运动试验，CS EMG、Pga和Pdi呈线性增加，而Pes呈线性下降，且均为运动强度的函数。在所有步态中，呼吸频率（fR）与步频（fS）一一对应。然而，当马匹慢跑和疾驰时观察到的fR与fS之间恒定的相位耦合关系，在马匹行走或小跑时并不存在。我们得出结论，生物力学力对运动马匹通气的贡献最小，膈膜在每次呼吸时始终呈阶段性活动，其总电活动和机械输出与运动性通气过度成正比。
