Patak A, Proske U, Turner H, Gregory J E
Department of Physiology, Monash University, Victoria, Australia.
Int J Dev Neurosci. 1992;10(1):81-92. doi: 10.1016/0736-5748(92)90009-o.
This is a report of the changes observed in the pattern of sensory innervation of muscle spindles in hindlimb muscles of kittens during the first four weeks of life. The structural analysis, made on teased, silver-stained preparations, was complemented by a series of recordings of afferent responses of kitten spindles during ramp-and-hold stretches of the muscle. The primary endings of spindles from newborn animals showed a large degree of variability in their branching pattern and branches formed a network across the intrafusal fibres. In older animals there was less variability and lateral branches of stem axons began to encircle the intrafusal fibres. The process of maturation was characterized by a more uniform shape of the endings and more complete, evenly spaced, annulospiral terminals. Recordings of the responses of primary endings of spindles during muscle stretch showed that several features of the adult response were already present in the newborn, although the overall rate of discharge was very much lower. It was concluded that the changes observed in the structure of the sensory endings of kitten spindles did not have clearly identifiable physiological correlates. It appears that an annulospiral shape of the sensory terminals is not a necessary prerequisite for the generation of stretch responses. The predominant factor which appears to determine the responses of spindles to stretch is the maturity of the intrafusal fibres, in particular, the bag2 fibre.
这是一份关于小猫出生后前四周后肢肌肉中肌梭感觉神经支配模式变化的报告。对 teased、银染制剂进行的结构分析，辅以在肌肉进行斜坡-保持拉伸时对小猫肌梭传入反应的一系列记录。新生动物肌梭的初级末梢在分支模式上表现出很大的变异性，分支在梭内纤维间形成网络。在年龄较大的动物中，变异性较小，主干轴突的侧支开始环绕梭内纤维。成熟过程的特征是末梢形状更均匀，以及更完整、间隔均匀的环螺旋末梢。肌肉拉伸时肌梭初级末梢反应的记录表明，尽管总体放电率要低得多，但新生动物中已经存在成年反应的几个特征。得出的结论是，在小猫肌梭感觉末梢结构中观察到的变化没有明显可识别的生理相关性。感觉末梢的环螺旋形状似乎不是产生拉伸反应的必要前提。似乎决定肌梭对拉伸反应的主要因素是梭内纤维的成熟度，特别是袋 2 纤维。
