Koterba A M, Wozniak J A, Kosch P C
Department of Physiological Sciences, HSC College of Veterinary Medicine University of Florida, Gainesville 32610, USA.
Equine Vet J. 1995 Jul;27(4):265-74. doi: 10.1111/j.2042-3306.1995.tb03075.x.
Changes in pattern of airflow, sequence of respiratory muscle activation and generated pressures were measured serially in a group of foals during the first year post partum, in order to describe the maturation of the equine breathing pattern. In neonatal foals, inspiration and expiration were both primarily active and airflow pattern was essentially monophasic. By age 1 year, foals displayed essentially the same breathing pattern previously described in adult horses, utilising a combination of active and passive inspiration and expiration to breathe around, rather than from, the relaxation volume of the respiratory system (Vrx). A strong temporal relationship during growth was found between the timing of changes observed in airflow pattern and in the neuromuscular strategy of breathing. The transition to the adult breathing pattern appeared to involve a time delay in activation of both inspiratory and expiratory muscle groups, establishing a passive and active component to both inspiration and expiration. Throughout the study period, concurrent with the increase in delay of abdominal muscle activation, the expiratory flow pattern became progressively more biphasic in appearance. The time of appearance of a consistent biphasic inspiratory flow pattern was considerably later, at approximately age 1 year and coincided with the appearance of a delay in inspiratory muscle activation. From our results, we conclude that the transition from the neonatal to the adult breathing strategy in the horse appears not to be induced by the time course of chest wall stiffening during maturation. While changes in relative body proportions and size of abdominal contents during growth may influence the transition in breathing, our results also indicate that respiratory control mechanisms play an essential role in the expression of the polyphasic breathing pattern.
为了描述马呼吸模式的成熟过程，在一组新生马驹产后的第一年中，连续测量了气流模式、呼吸肌激活顺序和产生的压力变化。在新生马驹中，吸气和呼气主要都是主动的，气流模式基本上是单相的。到1岁时，马驹表现出与之前描述的成年马基本相同的呼吸模式，利用主动吸气和呼气与被动吸气和呼气相结合的方式，围绕而非从呼吸系统的松弛容积（Vrx）进行呼吸。在生长过程中，气流模式变化的时间与呼吸的神经肌肉策略变化之间存在很强的时间关系。向成年呼吸模式的转变似乎涉及吸气和呼气肌群激活的时间延迟，从而在吸气和呼气中都建立了被动和主动成分。在整个研究期间，随着腹肌激活延迟的增加，呼气气流模式在外观上逐渐变得更加双相。持续双相吸气气流模式出现的时间要晚得多，大约在1岁时出现，与吸气肌激活延迟的出现同时发生。根据我们的结果，我们得出结论，马从新生到成年呼吸策略的转变似乎不是由成熟过程中胸壁变硬的时间进程所诱导的。虽然生长过程中相对身体比例和腹部内容物大小的变化可能会影响呼吸的转变，但我们的结果也表明，呼吸控制机制在多相呼吸模式的表达中起着至关重要的作用。
