CONTROL OF DYNAMIC AND STATIC NUCLEAR BAG FIBERS AND NUCLEAR CHAIN FIBERS BY GAMMA-AXONS AND BETA-AXONS IN ISOLATED CAT MUSCLE-SPINDLES
CONTROL OF DYNAMIC AND STATIC NUCLEAR BAG FIBERS AND NUCLEAR CHAIN FIBERS BY GAMMA-AXONS AND BETA-AXONS IN ISOLATED CAT MUSCLE-SPINDLES
复制标题
DOI：
10.1113/jphysiol.1977.sp011709
复制
发表时间：
1977-01-01
影响因子：
5.5
通讯作者：
WARD, J
中科院分区：
文献类型：
--
作者：
BOYD, IA;GLADDEN, MH;WARD, J
在动态γ刺激期间，具有血液供应的分离的猫肌梭中的核袋和核链梭内纤维的行为轴突，动态β轴突或静态. gamma。观察腹根细丝中的轴突并记录在静止和移动的胶片上。大多数纺锤体由1个动态γ控制。轴突（有时是β轴突）轴突）和3个静态. γ。轴突，其中1个通常是非选择性的分布。大多数梭状运动轴突仅控制纺锤体的一极。动态γ和β轴突仅在任何纺锤体中的2个核袋纤维中的1个中产生局灶性收缩，并且该纤维从未被静态γ激活。轴突最大强直性收缩是缓慢达到的，并且该纤维上的初级感觉螺旋仅被少量拉伸。这种纤维被命名为动态核袋纤维。静态γ轴突产生：仅在2个核袋纤维的第2个中的局灶性收缩;仅在核链纤维束中的局部收缩;或1个核袋纤维和核链纤维一起收缩。核袋纤维的最大强直收缩使其初级感觉螺旋显著伸展，达到平台期的时间相对较短。这种纤维被命名为静态核袋纤维。Ia传入放电的驱动由非选择性静态γ产生。轴突，经常通过静态γ。轴突单独控制核链纤维，可能是由于核链纤维中的机械振荡。它从来不是由dynamic. gamma制作的。轴突和1次仅由静态γ。轴突单独控制核袋纤维。动态γ的传导速度和静态γ。轴突广泛重叠，尽管是动态的。轴突从下端缺失，并且静态γ。支配核链纤维的轴突仅在速度范围的上端缺席。观察结果与纺锤体结构和组织化学相关。动态和静态核袋纤维分别对应于bag 1纤维和bag 2纤维。本文还讨论了梭运动轴突的动态和静态作用的可能起源以及动态和静态梭内系统在运动控制中的作用。
The behavior of nuclear bag and nuclear chain intrafusal fibers in isolated cat muscle spindles with a blood supply, during stimulation of dynamic .gamma. axons, dynamic .beta. axons or static .gamma. axons in ventral root filaments was observed and recorded on still and moving film. Most spindles were controlled by 1 dynamic .gamma. axon (sometimes a .beta. axon) and 3 static .gamma. axons, 1 of which was often non-selective in distribution. A large majority of fusimotor axons controlled 1 pole of the spindle only. Dynamic .gamma. and .beta. axons produced focal contraction in only 1 of the 2 nuclear bag fibers in any spindle and this fiber was never activated by static .gamma. axons. Maximal tetanic contraction was attained slowly and the primary sensory spiral on this fiber was stretched by a small amount only. This fiber was named the dynamic nuclear bag fiber. Static .gamma. axons produced either: focal contraction in the 2nd of the 2 nuclear bag fibers only; local contraction in the bundle of nuclear chain fibers only; or contraction in 1 nuclear bag fiber and the nuclear chain fibers together. Maximum tetanic contraction of this nuclear bag fiber stretched its primary sensory spiral considerably and the time to plateau was relatively short. This fiber was named the static nuclear bag fiber. Driving of the Ia afferent discharge was produced by non-selective static .gamma. axons, frequently by static .gamma. axons controlling nuclear chain fibers alone and was probably due to mechanical oscillation in nuclear chain fibers. It was never produced by dynamic .gamma. axons and on 1 occasion only by a static .gamma. axon controlling a nuclear bag fiber alone. The conduction velocities of dynamic .gamma. and static .gamma. axons overlapped extensively, though dynamic .gamma. axons were absent from the lower end, and static .gamma. axons innervating nuclear chain fibers only were absent from the upper end, of the range of velocities. The observations were correlated with spindle structure and histochemistry. Dynamic and static nuclear bag fibers corresponded with bag1 fibers and bag2 fibers, respectively. The possible origin of the dynamic and static actions of fusimotor axons and the role of the dynamic and static intrafusal systems in motor control are discussed.