van Lunteren E, Vafaie H, Miller M J
Department of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.
Respiration. 1996;63(2):88-93. doi: 10.1159/000196524.
Theophylline alleviates central and obstructive apneas of prematurity, and may improve adult obstructive sleep apnea. One mechanism of action appears to be a stimulatory effect on the motor output to upper airway dilator muscles. The purpose of the present study was to determine whether theophylline might have a second mechanism of action, namely that of improving the force and/or endurance of the pharyngeal dilator musculature. Rat sternohyoid muscle strips were studied in vitro and compared to diaphragm strips. The isometric twitch force and twitch kinetics of neither muscle were altered by theophylline (100 mg/l). Theophylline significantly slowed the rate at which the diaphragm fatigued during intermittent 40-Hz stimulation (p < 0.001). In contrast, theophylline produced no improvement in the fatigue resistance of the sternohyoid muscle. The degree of force potentiation during the early portion of the fatigue protocol was not altered by theophylline for either muscle. These results suggest that the mechanism by which theophylline improves obstructive apnea is unlikely to be due to a beneficial effect on pharyngeal dilator muscle force or endurance.
茶碱可缓解早产儿的中枢性和阻塞性呼吸暂停，且可能改善成人阻塞性睡眠呼吸暂停。其一种作用机制似乎是对支配上呼吸道扩张肌的运动输出产生刺激作用。本研究的目的是确定茶碱是否可能具有第二种作用机制，即改善咽部扩张肌的力量和/或耐力。对大鼠胸骨舌骨肌条进行体外研究，并与膈肌条进行比较。茶碱（100 mg/l）对两种肌肉的等长收缩力和收缩动力学均无影响。茶碱显著减慢了膈肌在40赫兹间歇性刺激过程中的疲劳速率（p < 0.001）。相比之下，茶碱对胸骨舌骨肌的抗疲劳能力没有改善。在疲劳试验早期阶段，茶碱对两种肌肉的力量增强程度均无改变。这些结果表明，茶碱改善阻塞性呼吸暂停的机制不太可能是对咽部扩张肌的力量或耐力产生有益影响。
