Korenaga S
Jpn J Physiol. 1980;30(3):313-31. doi: 10.2170/jjphysiol.30.313.
The ontogenic change in properties of muscle membrane and neuromuscular junctions in fast (m. extensor propatagialis longus; EPL and m. pectoralis major; PM) and slow (m. anterior latissimus dorsi; ALD) muscle fibers of normal and inherited dystrophic chickens were investigated. In normal and dystrophic EPL and ALD, the membrane potential increased between 3 and 6 weeks ex ovo, and remained much the same value until 30 weeks ex ovo. There was no apparent difference in membrane potential between both strains. In ALDs of both strains, the threshold depolarization for the spike generation remained the same until 10 weeks ex ovo but thereafter the spike became abortive in shape. In EPLs of both strains, the threshold potential shifted to a hyperpolarized level following the increase in membrane potential. In PM and EPL of both strains, length constant, time constant of the membrane, membrane resistance and cell diameter increased, whereas input resistance decreased. However, the above changes in the various membrane parameters appeared to be more significant in dystrophic chickens than in normal ones at 3-6 weeks ex ovo. A part of these changes in the various parameters could not be explained by increased cell diameter alone. Changes in the membrane property during the progress of aging in dystrophic chickens appeared simultaneously in both muscles. The properties of m.e.p.p.s. and e.p.p.s in ALD and EPL in the normal chicken showed specific patterns such as slow and fast muscles, respectively. However, in ALD and EPL, no difference in the properties of acetylcholine receptor and acetylcholine release from nerve terminals between both strains was observed. These results suggest that pathological changes in the muscle cell are evident both in the membrane and the contractile properties but not in the neuromuscular junction.
研究了正常和遗传性营养不良鸡的快肌（趾长伸肌；EPL和胸大肌；PM）和慢肌（背阔肌前部；ALD）中肌膜和神经肌肉接头特性的个体发育变化。在正常和营养不良的EPL和ALD中，出壳后3至6周膜电位升高，并在出壳后30周保持大致相同的值。两品系之间的膜电位没有明显差异。在两品系的ALD中，直到出壳后10周，产生动作电位的阈去极化保持不变，但此后动作电位的形状变得顿挫。在两品系的EPL中，随着膜电位的升高，阈电位向超极化水平移动。在两品系的PM和EPL中，长度常数、膜的时间常数、膜电阻和细胞直径增加，而输入电阻降低。然而，在出壳后3至6周，营养不良鸡的上述各种膜参数变化似乎比正常鸡更显著。这些参数的部分变化不能仅用细胞直径增加来解释。营养不良鸡衰老过程中膜特性的变化在两块肌肉中同时出现。正常鸡的ALD和EPL中微小终板电位和终板电位的特性分别呈现出慢肌和快肌的特定模式。然而，在ALD和EPL中，未观察到两品系之间乙酰胆碱受体特性和神经末梢乙酰胆碱释放的差异。这些结果表明，肌肉细胞的病理变化在膜和收缩特性方面都很明显，但在神经肌肉接头处不明显。
