van Lunteren E, Brass E P
Department of Medicine, Cleveland VA Medical Center, OH 44106, USA.
Respir Physiol. 1996 Sep;105(3):171-7. doi: 10.1016/0034-5687(96)00043-6.
Pharyngeal muscles play important roles in the maintenance of upper airway patency during sleep. The present study determined the extent of heterogeneity among pharyngeal muscles and the diaphragm in their metabolic profiles, and examined whether differences among muscles may account for previously described differences in their fatigue resistance. Cat and rat sternohyoid, geniohyoid, genioglossus (cat only) and diaphragm muscle were assayed for activities of the mitochondrial enzyme citrate synthase (CS), the glycolytic enzyme phosphofructokinase (PFK) and the cytosolic enzyme lactate dehydrogenase (LDH). CS activity varied among muscles in both species, being highest for genioglossus in cat and highest for diaphragm in rat. PFK activity was highest for genioglossus in cat, but did not differ among muscles in rat. LDH activity was lower for the genioglossus than the sternohyoid and diaphragm in cat. CS and PFK activities correlated positively, and LDH activity correlated negatively, with in vitro fatigue resistance assessed after 5 min of repetitive stimulation in cat. These data indicate close relationships between metabolic profiles, particularly oxidative capacity, and fatigue resistance of pharyngeal muscles in relationship to each other and to the diaphragm.
咽肌在睡眠期间对上呼吸道通畅的维持起着重要作用。本研究确定了咽肌与膈肌在代谢特征方面的异质性程度，并研究了肌肉之间的差异是否可以解释先前描述的它们在抗疲劳能力上的差异。对猫和大鼠的胸骨舌骨肌、颏舌骨肌、颏舌肌（仅猫）和膈肌进行了线粒体酶柠檬酸合酶（CS）、糖酵解酶磷酸果糖激酶（PFK）和胞质酶乳酸脱氢酶（LDH）活性的测定。两种物种的肌肉中CS活性各不相同，猫的颏舌肌中最高，大鼠的膈肌中最高。猫的颏舌肌中PFK活性最高，但大鼠的肌肉之间无差异。猫的颏舌肌中LDH活性低于胸骨舌骨肌和膈肌。在猫重复刺激5分钟后评估的体外抗疲劳能力方面，CS和PFK活性呈正相关，LDH活性呈负相关。这些数据表明，代谢特征，特别是氧化能力，与咽肌以及膈肌相互之间的抗疲劳能力密切相关。
