Eberstein A, Pachter B R
Department of Rehabilitation Medicine, New York University Medical Center, New York 10016.
Exp Neurol. 1992 Jun;116(3):240-5. doi: 10.1016/0014-4886(92)90003-9.
The isometric contractile characteristics of rat plantaris muscles were assessed 1, 3, 6, 9, and 12 months after resection of the L4 radicular nerve. After 1 month of partial denervation, twitch and tetanus were significantly lower (26.1 and 22.1%, respectively) than those of sham-operated rats. Plantaris muscle weight was reduced (22.5%), but twitch-to-tetanus ratio (TW/TT), time-to-peak, and one-half relaxation time were not changed significantly. At 3 months, average twitch force was normal but average tetanic force was significantly lower (27.1%) than control value. Muscle weight was reduced (28.9%), but TW/TT was increased by 31%. After 6 months, twitch, tetanus, and all other variables were similar to those of control rats. Normal twitch at 3 months indicates that all muscle fibers have been reinnervated by sprouting from L5 motor axons; however, the new synaptic contacts may not support the tetanic response. At 9 months, muscle force was again reduced and remained at about the same level at the 12-month interval. These results are consistent with the recovery and loss of function seen in poliomyelitis and the postpolio syndrome.
在切除L4神经根后1、3、6、9和12个月，评估大鼠跖肌的等长收缩特性。部分去神经支配1个月后，单收缩和强直收缩分别比假手术大鼠显著降低（分别为26.1%和22.1%）。跖肌重量减轻（22.5%），但单收缩与强直收缩比值（TW/TT）、峰值时间和半松弛时间无显著变化。3个月时，平均单收缩力正常，但平均强直收缩力显著低于对照值（27.1%）。肌肉重量减轻（28.9%），但TW/TT增加了31%。6个月后，单收缩、强直收缩和所有其他变量与对照大鼠相似。3个月时正常的单收缩表明所有肌纤维已由L5运动轴突发芽重新支配；然而，新的突触联系可能不支持强直反应。9个月时，肌肉力量再次降低，并在12个月时保持在大致相同的水平。这些结果与小儿麻痹症和小儿麻痹后遗症中所见的功能恢复和丧失一致。
