Sakata Yasuko, Ishige Kumiko, Ohtakara Tomohiro, Ito Yoshihisa
Department of Pharmacology, College of Pharmacy, Nihon University, 7-7-1 Narashinodai, Funabashi, Chiba 274-8555, Japan.
Neurosci Res. 2006 Jul;55(3):327-33. doi: 10.1016/j.neures.2006.04.003. Epub 2006 May 11.
We have shown previously that oral administration of a nutritive-tonic drink (NTD) improves scopolamine-induced memory impairment in the passive avoidance task and Morris water-maze in mice and that this action is attributable to the natural drug extracts, rather than synthetic drugs such as taurine and caffeine, in the NTD. In order to investigate the mechanism underlying the antiamnesic effects of the natural drug extracts, the effects of the extracts on the induction of long-term potentiation (LTP) was investigated in the dentate gyrus (DG) of normal and scopolamine-treated rats. Oral administration of natural drug extracts enhanced the induction of population spike amplitude induced by weak tetanic stimulation (30 pulses at 60 Hz). Scopolamine (0.3 mg/kg, i.p.) completely inhibited the induction of LTP induced by both weak and strong tetanic stimulation (100 pulses at 100 Hz). Natural drug extracts enhanced partially but significantly the induction of LTP by strong tetanus, but had a very weak effect on that induced by weak tetanus. These results suggest that LTP induced by strong tetanus is sensitive to natural drug extracts, and that the antiamnesic effect of the NTD is at least partly attributable to the LTP-improving effect of the natural drug extracts in the DG.
我们之前已经表明，口服一种滋补饮品（NTD）可改善东莨菪碱诱导的小鼠被动回避任务和莫里斯水迷宫中的记忆障碍，且这种作用归因于NTD中的天然药物提取物，而非牛磺酸和咖啡因等合成药物。为了研究天然药物提取物抗遗忘作用的潜在机制，我们在正常大鼠和经东莨菪碱处理的大鼠的齿状回（DG）中研究了提取物对长时程增强（LTP）诱导的影响。口服天然药物提取物可增强弱强直刺激（60Hz下30个脉冲）诱导的群体峰电位幅度的诱导。东莨菪碱（0.3mg/kg，腹腔注射）完全抑制了弱强直刺激和强强直刺激（100Hz下100个脉冲）诱导的LTP的诱导。天然药物提取物可部分但显著增强强强直刺激诱导的LTP的诱导，但对弱强直刺激诱导的LTP的影响非常微弱。这些结果表明，强强直刺激诱导的LTP对天然药物提取物敏感，且NTD的抗遗忘作用至少部分归因于天然药物提取物在DG中改善LTP的作用。
