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。
OBJECTIVE: To determine if chronic morphine treatment and acute morphine application affect the induction of long-term potentiation(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.
出处
《中国药学杂志》
EI
CAS
CSCD
北大核心
2004年第11期822-825,共4页
Chinese Pharmaceutical Journal
基金
国家自然科学基金资助(30271140)
