Structural and oxidative enzyme characteristics of the diaphragm.
Structural and oxidative enzyme characteristics of the diaphragm.
复制标题
隔膜的结构和氧化酶特征。
DOI：
10.1111/j.2042-3306.2002.tb05466.x
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Erickson,HH
中科院分区：
文献类型：
--
作者：
Poole,DC;Petrisko,RN;Anderson,L;Fedde,MR;Erickson,HH
在运动过程中，马可以分别达到超过200 ml/kg/min和1800 I/min的摄氧量和通气量。横膈膜是否有能力在训练马的吸气努力作出重大贡献还不清楚。为了研究马膈肌产生张力、肺移位和维持呼吸功能的潜力，我们测量了腹侧、内侧和背侧肋和脚膈内的膈肌厚度、肌肉长度和氧化酶活性（柠檬酸合酶）。在6匹成年马（5匹纯种马，1匹四分之一马;体重（平均值± s.e.）475 ± 14 kg，年龄4 ± 1岁），新鲜切除的膈肌质量为4.54 ± 0.19 kg，其中79%为肋膈，17%为脚膈，4%为中央腱。肋内侧区（2.1 ± 0.1 cm）明显厚于肋腹侧区（1.4 ± 0.1 cm）和肋背侧区（1.2 ± 0.2 cm）（P<0.05），脚膈明显厚于肋膈区（>3.2 ± 0.3 cm，P<0.05）。就肋隔膜而言，内侧肋（17.2 ± 1.0 cm）的切除肌肉长度最大（P<0.05），低于腹侧肋（<12.6 ± 1.5 cm）或背侧肋（<13.9 ± 1.8 cm）区域，因此预计内侧区域在吸气时表现出最大的绝对长度变化。柠檬酸合酶活性在整个膈肌中较高（40.8 ± 11.3至55.3 ± 9.7 μmol/g/min），但在不同区域之间无显著差异。马横膈膜的这些结构特征和氧化电位与横膈膜在马的运动期间对吸气努力提供显著和实质性贡献一致。因此，运动表现的临床和生理研究不应忽视横膈膜的潜在关键重要性。
During exercise, the horse can achieve oxygen uptakes and ventilations in excess of 200 ml/kg/min and 1800 I/min, respectively. Whether the diaphragm has the capacity to contribute substantially to inspiratory effort in the exercising horse is not known. To investigate the potential for the horse diaphragm to generate tension, lung displacement and sustain ventilatory function, we measured diaphragm thickness, muscle length and oxidative enzyme activity (citrate synthase) within the ventral, medial and dorsal costal and crural diaphragm. In the diaphragms of 6 mature horses (5 Thoroughbreds, one Quarter Horse; body mass (mean ± s.e.) 475 ± 14 kg, age 4 ± 1 years), the mass of the freshly‐excised diaphragm was 4.54 ± 0.19 kg of which 79% was the costal diaphragm, 17% the crural diaphragm and 4% the central tendon. The medial costal region (2.1 ± 0.1 cm) was significantly thicker (P<0.05) than either the ventral (1.4 ± 0.1 cm) or dorsal (1.2 ± 0.2 cm) costal regions and the crural diaphragm was significantly thicker (>3.2 ± 0.3 cm, P<0.05) than any costal diaphragm region. With respect to the costal diaphragm, excised muscle length was greatest (P<0.05) in the medial costal (17.2 ± 1.0 cm) than either the ventral costal (<12.6 ± 1.5 cm) or dorsal costal (<13.9 ± 1.8 cm) regions and therefore the medial region would be expected to exhibit the greatest absolute length change on inspiration. Citrate synthase activity was high throughout the diaphragm (40.8 ± 11.3 to 55.3 ± 9.7 μmol/g/min), but was not significantly different among regions. These structural characteristics and the oxidative potential of the horse diaphragm are consistent with the diaphragm providing a significant and substantial contribution to the inspiratory effort during exercise in the horse. Consequently, clinical and physiological investigations of exercise performance should not ignore the potentially crucial importance of the diaphragm.