Ota Fumikazu, Connor Nadine P, Konopacki Richard
Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin, Madison, Wisconsin, USA.
Ann Otol Rhinol Laryngol. 2005 Oct;114(10):799-803. doi: 10.1177/000348940511401010.
Fatigue and weakness are well-known signs of aging that are related to sarcopenia, or loss of skeletal muscle mass, organization, and strength. Sarcopenia may affect swallowing. The tongue plays a vital role in swallowing, but there is limited knowledge regarding age-related changes in lingual muscle contractile properties. Our purpose was to determine whether alterations in tongue force, temporal features of tongue muscle contraction, and fatigability are manifested as a function of aging in old rats.
We evaluated tongue muscle contractile properties in young and old Fischer 344/Brown Norway rats. Contractions were elicited via bilateral electrical stimulation of the hypoglossal nerves.
Maximum tongue forces and fatigability were not significantly altered in old animals, but aging was associated with significantly longer twitch contraction time and longer half-decay recovery time intervals (p < .01).
The results indicated that old animals generated sufficient maximum tongue forces, but were slower in achieving these forces than young animals. These findings are consistent with reports of altered temporal parameters of tongue actions during swallowing in humans, and suggest that a disruption in the timing of muscle contraction onset and recovery may contribute to the altered tongue kinetics observed with aging.
疲劳和虚弱是与肌肉减少症相关的衰老的常见迹象，肌肉减少症即骨骼肌质量、结构和力量的丧失。肌肉减少症可能会影响吞咽。舌头在吞咽中起着至关重要的作用，但关于舌肌收缩特性的年龄相关变化的了解有限。我们的目的是确定老年大鼠的舌力、舌肌收缩的时间特征和疲劳性的改变是否随衰老而表现出来。
我们评估了年轻和老年Fischer 344/布朗挪威大鼠的舌肌收缩特性。通过双侧舌下神经电刺激引发收缩。
老年动物的最大舌力和疲劳性没有显著改变，但衰老与抽搐收缩时间显著延长和半衰减恢复时间间隔显著延长有关（p < 0.01）。
结果表明，老年动物能产生足够的最大舌力，但达到这些力的速度比年轻动物慢。这些发现与人类吞咽时舌头动作的时间参数改变的报道一致，并表明肌肉收缩开始和恢复时间的中断可能导致衰老时观察到的舌动力学改变。
