Natural drug extracts for a nutritive-tonic drink, promotes the induction of long-term potentiation in rat hippocampal dentate gyrus in vivo.

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.

Effect of a nutritive-tonic drink on stress-induced serum glucocorticoid in the mouse.

We evaluated stress during "restraint with gnawing (R+G+)" and "restraint without gnawing (R+G-)" in a mouse system. R+G- induced a higher serum glucocorticoid level than R+G+. Zena F-III (a nutritive-tonic drink prescribed as "Kampo", a traditional Japanese medicine with its origin in Chinese medicine) reduced the glucocorticoid elevation in R+G+, but not in R+G-. These results support the hypotheses that (i) activity, such as gnawing, which potentially leading to escape from distress, reduces the severity of emotional distress and (ii) Zena F-III reduces the severity of mental or emotional fatigue, or increases motivation, in a stressful situation that the animal can manage itself.

Effect of nutritive and tonic crude drugs on physical fatigue-induced stress models in mice.

The present study was undertaken to investigate the acute anti-fatigue effect of a liquid nutritive and tonic crude drugs (NTDs) on stress induced in mice. After forced walking for 3 or 6h, the NTDs (applied orally, 10 ml/kg) significantly increased locomotor activity, while the administration of NTDs after rapid eye movement (REM) sleep deprivation stress and after immobilization stress did not show a specific effect, having a similar effect as the vehicle with added vitamins, taurine and caffeine. The administration of NTDs after freezing due to electric shock stress showed a specific effect which was not seen in other control groups, water, vehicle (ethanol) and vehicle including vitamins, taurine and caffeine and so resemble the specific effect of NTDs in the stress of forced walking. The present results indicate that the NTDs produced an anti-fatigue effect on the decreased locomotor activity after forced walking and immobility induced by electric stimulation. However, the crude drugs were not effective in improving immobility after sleep deprivation or immobilization stress.