【摘要】 目的 观察急性和慢性吗啡应用对大鼠内嗅皮质外侧穿通纤维-CA3区直接通路突触传递长时程增强(LTP)的影响,并进一步研究其作用机制。方法 慢性腹腔注射吗啡建立SD大鼠吗啡依赖模型,从海马CA3区急性给药,在体记录由刺激内嗅皮质外侧穿通纤维(lateral perforant path,LPP),所诱发的CA3区锥体细胞群体峰电位(population spike,PS),并观察高频刺激引起的LTP效应。结果 急性给予CA3区终浓度1×10-6mol·L-1吗啡能增强基础PS及PS的LTP效应(P<0.05),这种增强作用能被μ-受体拮抗剂纳络酮阻断。而长期给予吗啡戒断24 h后,LTP的诱导被抑制(P<0.05);CA3区急性给予吗啡能恢复被损害的LTP。结论 阿片肽系统参与了EPP-CA3区直接通路的LTP诱导,慢性吗啡应用造成了此通路突触传递的适应性变化。更多还原

【Abstract】 OBJECTIVE To determine if chronic morphine treatment and acute morphine application affect the induction of long-term po-tentiation( LTP) of hippocampal CA3 region in rats differently.METHODS The population spike (PS) from pyramidal cell of CA3 region was recorded in vivo following stimulation of lateral perforant path (LPP) .For the induction of LTP,4 trains (50 shocks/train, 500Hz) of high-frequency tetanic stimulations were given to LPP. Before tetanus delivery, morphine and naloxone were injected into CA3 region in different group respectively. RESULTS Single application of morphine in hippocampal CA3 region augmentation LTP of LPP-CA3 region by 50% . Naloxone, the opioid receptor antagonist, however, inhibited the augmentation capacity of morphine on LTP, also blocked the induction of LTP in control group.Morphine withdrawal attenuatation LTP of LPP-CA3 region by 60% .Re-exposure to morphine restored LTP of withdrawal rats. CONCLUSION Morphine as well as morphine dependence may interact with the induction of LTP of LPP-CA3 region. Acute morphine application augmented synaptic function,while chronic morphine treatment may significantly modulate synaptic plasticity.更多还原