Davis G R, McClellan A D
Division of Biological Sciences, University of Missouri, Columbia 65211.
Brain Res. 1993 Jan 29;602(1):131-7. doi: 10.1016/0006-8993(93)90252-i.
In larval lamprey 4 weeks after a spinal transection locomotor patterns were usually complete along the body in whole animals. In in vitro preparations locomotor activity was restricted to a few millimeters below the transection. Retrograde labeling indicated that descending axons from a few brainstem neurons had grown through the transection site and probably directly activate the rostral spinal locomotor networks, but no direct descending projections were found to the caudal spinal cord. Thirty-two weeks after spinal transection locomotor activity was recorded at long distances below the transection in both whole animals and in vitro preparations. The number of brainstem neurons projecting to the rostral spinal cord below the transection appeared near normal while there was a reduced but significant projection to the caudal spinal cord. Thus, at long recovery times it appears that regenerated descending axons can directly activate the motor networks in both the rostral and caudal spinal cord and initiate locomotor activity, as is the case in normal animals.
在七鳃鳗幼体中，脊髓横断4周后，整个动物身体的运动模式通常是完整的。在体外制备物中，运动活性局限于横断部位下方几毫米处。逆行标记表明，来自少数脑干神经元的下行轴突已经穿过横断部位，可能直接激活了脊髓头端的运动网络，但未发现有直接的下行投射至脊髓尾端。脊髓横断32周后，在整个动物和体外制备物中，均在横断部位下方很长距离处记录到了运动活性。投射至横断部位下方脊髓头端的脑干神经元数量接近正常，而投射至脊髓尾端的数量减少但仍显著。因此，在长时间恢复后，再生的下行轴突似乎能够直接激活脊髓头端和尾端的运动网络并引发运动活性，这与正常动物的情况相同。
