Houle J D, Skinner R D, Garcia-Rill E, Turner K L
Department of Anatomy, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
Exp Neurol. 1996 Jun;139(2):278-90. doi: 10.1006/exnr.1996.0101.
Previously injured dorsal roots were electrically stimulated to determine if regenerating sensory axons can form physiologically active synaptic contacts with neurons within fetal spinal cord tissue transplants. Dorsal rootlets, sectioned at their spinal cord entry zone, were apposed to intraspinal transplants of fetal spinal cord tissue grafted along each side of a nerve growth factor treated nitrocellulose implant. Two to six months later, the rootlets were transected between the spinal cord and their respective ganglia and electrically stimulated. Evoked potentials were recorded from the dorsal surface of the transplant, but were absent from adjacent ipsilateral and contralateral spinal cord regions. A glass micropipette was advanced through the transplant and used to record intramedullary field potentials evoked by dorsal root stimulation. Maximal negative potentials occurred 400-700 micron below the dorsal surface of the transplant, shifting to positive potentials deeper into the transplant. Additionally, both spontaneous and electrically evoked single neuronal action potentials were observed along the microelectrode track. Evoked potentials were abolished following transaction of the rootlets between the stimulation site and the transplant. Immunocytochemical evidence of the production of fos protein following electrical stimulation of the regenerated dorsal rootlets was demonstrated within transplant neurons and some ventrally located host neurons, providing an anatomical correlate to the electrophysiological recordings of synaptic activation. These results provide evidence of the structural and functional integration of regenerated sensory axons with both transplant and host neurons.
对先前受损的背根进行电刺激，以确定再生的感觉轴突是否能与胎儿脊髓组织移植体内的神经元形成具有生理活性的突触联系。在脊髓进入区切断的背根小支，与沿神经生长因子处理过的硝酸纤维素植入物两侧移植的胎儿脊髓组织的脊髓内移植体相贴合。两到六个月后，在脊髓与其各自的神经节之间切断背根小支并进行电刺激。从移植体的背表面记录到诱发电位，但在相邻的同侧和对侧脊髓区域未记录到。将一根玻璃微电极推进穿过移植体，用于记录背根刺激诱发的髓内场电位。最大负电位出现在移植体背表面下方400 - 700微米处，在移植体更深处转变为正电位。此外，沿着微电极轨迹还观察到了自发的和电诱发的单个神经元动作电位。在刺激部位与移植体之间切断背根小支后，诱发电位消失。在移植神经元和一些位于腹侧的宿主神经元内，证实了再生背根小支电刺激后fos蛋白产生的免疫细胞化学证据，为突触激活的电生理记录提供了解剖学关联。这些结果提供了再生感觉轴突与移植神经元和宿主神经元在结构和功能上整合的证据。
