Fujitsuka C, Fujitsuka N, Diwan F H, Hama K, Sokabe M, Ito F
Department of Physiology, Nagoya University School of Medicine, Japan.
J Neurocytol. 1990 Apr;19(2):175-86. doi: 10.1007/BF01217296.
Changes in the density of intramembrane particles (IMPs) of sensory nerve terminals in the bullfrog muscle spindle were correlated with recovery in the response of the spindle to stretch during postcrush reinnervation. A few IMPs on the protoplasmic (P) face in summer experiments (June to October) reappeared by the 3rd week after the nerve crush, then rapidly increased to 110% and 120% of control values 2 and 2.5 months after the crush. Afferent responses to stretch could be recorded after the mean IMP density on the P-face in terminal branches had recovered to more than 25% of the control value. The discharge rate showed a plateau pattern during the period of the excessive IMPs. This was supplanted by a normal pattern after a myelinated branch of the sensory axon was cut. The IMPs in winter experiments (November to April) reappeared by day 90 after nerve crush, and then slowly increased. The sustained responses to stretch reappeared after 5 months, when the mean IMP density on the P-face was restored to 25% or more of the control. Neither excessive density of the IMPs nor plateau pattern of the discharge rate were observed in winter experiments. The relation between the regenerated IMP densities and the functional recovery is discussed.
牛蛙肌梭感觉神经末梢膜内颗粒（IMPs）密度的变化与挤压伤后再支配过程中肌梭对牵张反应的恢复相关。夏季实验（6月至10月）中，神经挤压后第3周，原生质（P）面上的一些IMPs重新出现，然后在挤压后2个月和2.5个月迅速增加至对照值的110%和120%。当终末支P面上的平均IMPs密度恢复到对照值的25%以上时，可记录到对牵张的传入反应。在IMPs过多的时期，放电率呈平台模式。在感觉轴突的有髓支被切断后，这种模式被正常模式所取代。冬季实验（11月至4月）中，神经挤压后第90天IMPs重新出现，然后缓慢增加。5个月后，当P面上的平均IMPs密度恢复到对照值的25%或更高时，对牵张的持续反应重新出现。冬季实验中未观察到IMPs密度过高或放电率呈平台模式的情况。文中讨论了再生的IMPs密度与功能恢复之间的关系。
