大鼠后根第一级传入纤维在脊髓胶状质内的溃变和突触联系

DEGENERATION AND SYNAPTIC RELATIONSHIPS OF THE DORSAL ROOT AFFERENT FIBERS IN THE SUBSTANTIA GELATINOSA OF THE RAT

用切断后根方法在透射电镜下观察了大鼠后根第一级传入纤维在脊髓胶状质内的溃变和突触联系。切断脊神经后根24小时后,胶状质内出现明显的溃变终末。量最多又持续时间最长的溃变是电子致密型溃变,此外,也观察到了少数的电子透明型溃变和神经微丝型溃变;溃变终末大部分位于胶状质突触小球的中央。据统计,电子致密型溃变作为突触前成分与胶状质内的树突或树突棘形成轴—树突触者占98.8%,作为突触后成分与周围轴突形成轴—轴突触者占1.2%。

Thirty rats were used in this study.The dorsal rhizotomies were per formed unilaterally at lumbar levels L4,L5,L6.Following 24h to 28 days degeneration periods the substantia gelatinosa was removed and ultrathin sections were made and studied by electron microscopy.The results were as follows:There were degenerating profiles in the substantia gelatinosa of the rat from 24h on after rhizotomy.The main degeneration pattern was the electron dense degeneration,bat there were also a few electron lucent degenerating terminals and the nerofilamentous degenerating ones.Most of the primary afferent fibers to the substantia gelatinosa ended as the central profiles in glomerular complexes,98.8%of the synaptic contacts were axodendritic synapses with the degenerating terminals as the presynaptic element,1.2%formed axoaxonic synapse with the degenerating terminals,as the postsynaptic element.