Brown M C, Holland R L, Hopkins W G, Keynes R J
Brain Res. 1981 Apr 6;210(1-2):145-51. doi: 10.1016/0006-8993(81)90891-x.
Certain muscles of the mouse and rat have been studied in order to assess how far a signal from denervated muscle can spread to elicit terminal sprouting from intact endplates. Denervation of the muscles surrounding the rat foot 4th lumbrical muscle caused no terminal sprouting in the 4th lumbrical itself. In the hemidenervated mouse gluteus maximus terminal sprouting was restricted to the central region of the muscle where innervated and denervated fibres intermingle. There was no enhancement of such sprouting if the underlying and closely apposed gluteus medius was simultaneously denervated. Hemidenervation of the mouse diaphragm and interscutularis, where intact endplates lie near to denervated muscle fibres, produced no terminal sprouting. Hemidenervation of the mouse platysma, where intact endplates often lie adjacent to denervated muscle fibres, similarly produced no significant response. However, all muscles were capable of producing extensive terminal sprouting in response to paralysis induced by botulinum toxin. The stimulus for terminal sprouting produced by an inactive muscle fibre must therefore be effective only on the fibre's own terminal or immediately adjacent terminals.
为了评估来自失神经肌肉的信号能在多大程度上扩散以引发完整终板的终末发芽，研究了小鼠和大鼠的某些肌肉。对大鼠第四蚓状肌周围的肌肉进行去神经支配，并未导致第四蚓状肌本身出现终末发芽。在半去神经支配的小鼠臀大肌中，终末发芽局限于神经支配和去神经支配纤维相互交织的肌肉中央区域。如果同时对其下方紧密相邻的臀中肌进行去神经支配，这种发芽并不会增强。在小鼠膈肌和肩胛下肌中，完整终板靠近去神经支配的肌纤维，但半去神经支配并未产生终末发芽。在小鼠颈阔肌中，完整终板常常紧邻去神经支配的肌纤维，半去神经支配同样未产生明显反应。然而，所有肌肉在肉毒杆菌毒素诱导的麻痹作用下都能够产生广泛的终末发芽。因此，由无活性肌纤维产生的终末发芽刺激必须仅对该纤维自身的终末或紧邻的终末有效。
