吗啡依赖大鼠脊髓Ⅱ板层初级传入纤维突触性终末数量变化的电镜定量研究

CHANGES OF SYNAPTIC TERMINAL NUMBER OF PRIMARY AFFERENT FIBERS IN SPINAL CORD LAMINA Ⅱ OF MORPHINE DEPENDENT RAT-AN EM QUANTITATIVE STUDY

目的 应用电镜定量方法探讨在吗啡依赖条件下 ,大鼠背根节感觉神经元发出的初级传入纤维能否在脊髓 板层侧支出芽和建立新的突触。 方法 用光镜体视学方法测知吗啡依赖组和对照组大鼠 L4脊髓 板层横切面积没有差异的情况下 ,直接比较了两组动物脊髓 板层神经毡单位面积内突触性终末的数量变化。 结果 吗啡依赖组脊髓 板层来自初级传入纤维的突触性终末数 ,明显多于对照组的初级传入纤维突触性终末数。其中来自无髓传入纤维的突触性终末数与对照组同类型的突触性终末数比较增加 6 1%。来自有髓传入纤维的突触性终末数比对照组增多 70 %。尤其是来自含有致密核芯小泡的初级传入纤维突触性终末数比对照组多 98%。 结论 吗啡可能促进初级传入纤维在脊髓

Objective\ Whether the primary afferent fibers given rise by sensory neuron in dorsal root ganglion of rat could make collateral sprouting and form new synapses in spinal lamina Ⅱ under the morphine dependence was explored with EM quantitative method. Methods\ The number of synaptic terminals in the unit area of neuropil of L\-4 spinal lamina Ⅱ was compared between morphine dependent and control rats,because there was no significant change in the crosscut area of L\-4 spinal lamina Ⅱ of two groups of animal,which was estimated by aid of LM stereological method. Results\ The number of synaptic terminals from primary afferent fibers in spinal lamina Ⅱ in morphine dependent group was significantly more than that in control group,among which the number of synaptic terminals from unmyelinated afferent fibers increased 61%.The number of synaptic terminals from myelinated afferent fibers was 70% more than that in control group.In particular,the number of synaptic terminals containing dense\|core vescles from the primary afferent fibers went up 98% over that of control group. Conclusion\ Morphine may promote the collateral sprouting and synaptogenesis of primary afferent fibers in spinal lamina Ⅱ.\;