Christiansen S P, Soulsby M E, Seifen E E
Department of Ophthalmology, Jones Eye Institute, Little Rock, AR, USA.
Invest Ophthalmol Vis Sci. 1995 Nov;36(12):2547-50.
In a previous study, the authors found that recession of an extraocular muscle resulted in atrophy of both the recessed muscle and its antagonist. To determine if atrophy, caused by weakening of an extraocular muscle, results in changes in developed tension in the antagonist, the authors studied force development of the cat lateral rectus muscle after adductor weakening.
Tenotomy of the left inferior, medial, and superior rectus muscles was performed in 18 cats. At 3, 6, and 12 weeks after surgery, the right (control) and left lateral rectus muscles were exposed through a lateral orbitotomy and were attached to isometric force transducers. Length-tension curves were obtained by direct muscle stimulation using bipolar contact electrodes at 0.1 Hz and 50% suprathreshold stimulus intensity. In addition, peak tetanic tension was measured at the optimal resting tension using a 5-second stimulus train at 200 Hz. Pooled data from the operative and control muscles at each postoperative interval were compared.
Three weeks after adductor weakening, a 28% decrease in maximal single-twitch tension was seen in the left lateral rectus muscle when compared with controls. This difference disappeared at 6 weeks. No statistically significant changes in peak tetanic tension occurred at any time interval after surgery.
Adductor weakening results in a transient decrease in single-twitch tension in the antagonist lateral rectus muscle in the cat.
在之前的一项研究中，作者发现眼外肌后退会导致后退肌肉及其拮抗肌均发生萎缩。为了确定眼外肌减弱引起的萎缩是否会导致拮抗肌的张力变化，作者研究了内收肌减弱后猫的外直肌的力量发展情况。
对18只猫进行左眼下直肌、内直肌和上直肌的腱切断术。在术后3周、6周和12周，通过外侧眶切开术暴露右侧（对照）和左侧外直肌，并将其连接到等长力传感器上。使用双极接触电极以0.1Hz和50%阈上刺激强度直接刺激肌肉，获得长度-张力曲线。此外，使用200Hz的5秒刺激序列在最佳静息张力下测量强直收缩峰值张力。比较每个术后间隔手术肌肉和对照肌肉的汇总数据。
内收肌减弱3周后，与对照组相比，左侧外直肌的最大单收缩张力下降了28%。这种差异在6周时消失。术后任何时间间隔强直收缩峰值张力均未发生统计学显著变化。
内收肌减弱导致猫拮抗肌外直肌的单收缩张力短暂下降。
