吗啡耐受与依赖对大鼠交感神经节快兴奋性突触传递的影响

目的研究吗啡(Mor)耐受与依赖对大鼠交感神经节快兴奋性突触传递的影响。方法制备正常对照大鼠和Mor耐受与依赖大鼠的离体交感神经节———颈上神经节(SCG)标本,运用细胞内生物电记录技术研究Mor耐受与依赖对大鼠交感神经节快兴奋性突触传递的影响。结果研究发现:①Mor(0.1~1.0 mmol.L-1)能可逆性抑制正常对照组大鼠SCG细胞的快兴奋性突触后电位(Fast exc itatorypostsynaptic potential,f-EPSP);②与正常对照组相比,Mor(0.5 mmo.lL-1及1.0 mmo.lL-1)对Mor耐受与依赖大鼠SCG细胞的f-EPSP的抑制效应明显降低;③对正常对照组大鼠SCG细胞f-EPSP无影响的纳洛酮(Nal,0.1 mmol.L-1)能增加Mor耐受与依赖大鼠SCG细胞的f-EPSP。④Mor耐受与依赖组大鼠和正常对照组和SCG细胞的膜电位(RMP)和膜电阻(Rm)差异无显著性。结论Mor耐受与依赖大鼠的交感神经节的快兴奋性突触传递形成了对Mor的耐受和依赖。

Effects of morphine tolerance and dependence on the fast excitatory synaptic transmission in sympathetic ganglia of rats

Aim To study effects of morphine tolerance and dependence on the fast excitatory synaptic transmission in sympathetic ganglia of rats.Methods The isolated sympathetic ganglia,superior cervical ganglia(SCG), were made from control and morphine tolerant and dependent rats respectively.Effects of morphine tolerance and dependence on the fast excitatory synaptic transmission in rat sympathetic ganglia were studied by means of intracellular recording technique.Results ① Morphine(0.1～1.0 mmol·L~(-1))reversibly inhibited the amplitude of the fast excitatory postsynaptic potentials(f-EPSPs) in SCG neurons of control rats.② Compared with control group,inhibitory effects of morphine(0.5 mmol·L~(-1) and 1.0 mmol·L~(-1)) on f-EPSPs in SCG neurons of morphine tolerant and dependent rats were obviously decreased;③ Naloxone(0.1 mmol·L~(-1)),which had no significantly effect on f-EPSPs in SCG neurons of control rats,could reversibly facilitate the amplitude of f-EPSPs in SCG neurons of morphine tolerant and dependent rats;④ No significant difference of RMP and Rm was founded between SCG neurons of control and morphine tolerant and dependent rats.Conclusion The morphine tolerant and dependent of the fast excitatory synaptic transmission in rat sympathetic ganglia has been formed in morphine tolerant and dependent rats.