【摘要】 目的　从齿状回长时程增强效应 (LTP)方面研究锂的治疗作用机理。方法　细胞外记录离体海马脑片神经元兴奋性突触后电位 (EPSP)。结果锂可逆地增强EPSP的幅度。高频刺激 (10 0Hz ,1s)对照组大鼠海马穿通纤维 ,在海马齿状回 (DG)区记录的EPSP幅度会持续增高 ,可以诱导出明显的突触后LTP。若用 10mmol·L- 1锂处理大鼠海马脑片 ,则诱导的LTP幅度明显降低 ,但低浓度锂 (2 ,6mmol·L- 1)不影响LTP的幅度 ;10mmol·L- 1锂明显抑制海马脑片DG区的脉冲间隔 (IPI)为 5 0ms的双脉冲易化效应 (PPF) ,而低浓度锂 (2 ,6mmol·L- 1)处理则不影响PPF(IPI,5 0ms) ;在不同的细胞外钙浓度下 ,用 10mmol·L- 1锂处理过的海马脑片PPF受到的抑制程度不同。结论　锂可能通过突触前的机理来抑制海马DG区LTP的幅度 ,这种抑制效应与锂的临床治疗狂躁症及其副作用之间的关系尚需进一步的研究。更多还原

【Abstract】 AIM To investigate the mechanism of the-rapeutic action of lithium with respect to long-term potentiation(LTP) elicited in dentate gyrus(DG) region of rat hippocampus. METHODS To use conventional extracellular recording technique in hippocampal slices in vitro . RESULTS Lithium was found to reversibly increase excitatory postsynaptic potentials in the DG region of rat hippocampus. Under control conditions, titanic stimulation (100 Hz, 1 s) of medial perforans pathway induced LTP. Acute treatment of low concentration lithium (2, 6 mmol·L -1 ) did not affect the LTP induced by titanic stimulation, while its higher concentration (10 mmol·L -1 ) inhibited the amplitude of LTP in the DG region of rat hippocampus. Furthermore, lithium treatment (10 mmol·L -1 ) decreased paired-pulse facilitation (PPF) measured at 50 ms inter-pulse interval while, at lower concentrations, lithium treatments (2, 6 mmol·L -1 ) did not affect PPF significantly. We also found that the effects of lithium (10 mmol·L -1 ) on PPF were different at different o. CONCLUSION Lithium can inhibit the LTP magnitude in rat hippocampus probably through presynaptic mechanisms. These alterations of neurophysiological responses may be related to the therapeutic action of lithium salts in mania and depression as well as producing side effects of lithium chemotherapy.更多还原