(-),(+)黄皮酰胺对大鼠海马突触传递功能的不同影响

采用细胞外电生理记录法记录了低频刺激所诱发的麻醉大鼠海马齿状回颗粒细胞层群峰电位(PS)并比较了侧脑室注射(-),(+)黄皮酰胺对PS及强直刺激所诱导的长时程增强效应(LTP)作用。结果表明:低剂量(1nmol)时,(-)或(+)黄皮酰胺都对基础状态下的PS没有影响。对LTP(+)黄皮酰胺也无作用,(-)黄皮酰胺表现为增强作用;将剂量提高至4nmol时,(-)黄皮酰胺对基础PS和LTP都有增强作用且对LTP的作用表现出一定的剂量依赖性,(+)黄皮酰胺对PS仍无影响,对LTP有一定的抑制作用。提示黄皮酰胺对海马齿状回突触传递活动的作用具有光学选择性,这一结果有力地支持了(-)黄皮酰胺促智作用的行为学和神经生化学研究结果。

DIFFERENCE BETWEEN THE EFFECTS OF (-) CLAUSENAMIDE AND (+) CLAUSENAMIDE ON THE SYNAPTIC TRANSMISSION IN THE DENTATE GYRUS OF ANESTHETIZED RATS

With the extracellular recording technique, the basal synaptic responses (population spike, PS) evoked by low frequency test stimulation in the dentate gyrus of anesthetized rats was recorded and the effects of (-) and (+) clausenamide(icv) on the PS and long-term potentiation (LTP) induced by tetanus (50 pulses at 200 Hz) were observed. The results showed that: (1) at a lower dose (1 nmol), (+) clausenamide showed no effect on either the basal PS or LTP, (-) clausenamide did not affect the basal PS but enhanced the magnitude of LTP. (2) At a higher dose (4 nmol), (-) clausenamide not only potentiated the basal PS but also dose-dependently augmented the magnitude of LTP. Meanwhile, (+) clausenamide did not affect the basal PS but attenuated the magnitude of LTP. These results suggest that the effects of clausenamide on the synaptic transmission in the dentate gyrus depend on its chirality. The potentiating effects of (-) clausenamide on synaptic transmission in hippocampus strongly support our previous behavioral and neurobiochemical studies on the nootropic action of (-) clausenamide.