【摘要】 目的:从离子通道角度研究吗啡对中枢神经系统兴奋性及抑制性突触传递的作用,以探讨吗啡镇痛机制。方法:原代培养新生Wistar大鼠的海马神经元。采用膜片钳技术研究吗啡对其兴奋性及抑制性突触后电流及谷氨酸诱发电流的影响。结果:①吗啡可明显增强海马神经元兴奋性突触传递,加吗啡后自发兴奋性突触后电流发放频率增加了207.8%(t=42.1828,P<0.01)。此作用可被阿片受体阻断剂纳洛酮阻断;②吗啡对微小兴奋性突触后电流的发放频率及谷氨酸诱发电流的幅度没有明显影响(t=0.962,t=0.791,P>0.05);③吗啡可明显抑制神经元自发抑制性突触后电流,纳洛酮可拮抗吗啡作用(P<0.01)。结论:吗啡对海马神经元的兴奋作用不是由于吗啡直接作用于兴奋性氨基酸—谷氨酸突触传递过程,而是可能由于抑制了抑制性中间神经元,间接产生的兴奋达到镇痛作用。更多还原

【Abstract】 AIM:To investigate the effects of morphine on synaptic transmission of neuron s of central nervous system and to understand its mechanisms. METHODS:The hippocampus neurons were isolated from newborn Wistar rats for pr imary culture, and whole-cell patch-clamp technique was employed to observe the excitatory and spontaneous inhibitory postsynaptic currents(EPSC,sIPSC) and glutamate-evoked current before and after morphine treatment. RESULTS:sEPSC of the hippocampal neurons was increased by 207.8% (t=42.1828, P< 0.01) after morphine application,and the effect was blocked by opioid antagon ist naloxone.The frequency of mEPSC and the amplitude of glutamate-evoked curr ent of the hippocampal neurons did not undergo significant changes after morphin e treatment(t=0.962,0.791,respectively,P >0.05).Morphine markedly inhibited sIPS C of the hippocampal neurons, the effect of which was blocked by naloxone(P< 0.0 1). CONCLUSION:The excitatory effect of morphine on hippocampal neurons is not du e to the direct action of morphine on glutamate synapses transmission,but can be a result of the inhibition on the interneurons,or, through the “ disinhibition ” mechanism.更多还原