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Objective To study the effects of different color light stimulus, duration of stimulus and day/night training on the incentive conditioned reflex of rats,and to provide a data basis for the methodology of incentive conditional reflection experiments. Methods Three experiments were included in this study. During the experiment 1, a total of 30 male 8-week-old Wistar rats were divided into three groups:red light stimulation group,yellow light stimulation group and blue light stimulation group. During the experiment 2, a total of 32 male 8-week-old Wistar rats were divided into three groups:the group I(with a light stimulation duration of 10 s), the group II(with a light stimulation duration of 30 s), and the group III(with a light stimulation duration of 60 s). During the experiment 3,a total of 16 male 8-week-old Wistar rats were randomly divided into two groups,of which the first group was trained at 9:00 a.m. every day, and the second group was trained at 21:00 every day. All the laboratory animals were given reward conditioned reflex training, and indicators such as the number of correct nose pokes,the number of incorrect nose pokes,the ratio of correct nose pokes and so on were counted and calculated. Results During the experiment 1,there was no significant difference in the numbers of correct nose pokes and incorrect nose pokes,movement distances and average speeds of the rats among the three groups. During the experiment 2,compared with the group with a light duration of 10 s,the rats in the groups with a light duration of 30 s or 60 s had a higher number of correct nose pokes(P< 0.05). Moreover,on the 13th and 14th days,the ratio of correct nose pokes of the group with a light duration of 30 s was significantly higher than that of the group with a light duration of 10 s(P< 0.001). During the experiment 3,there were no significant differences in the number of correct nose pokes and the nose poke accuracy of the rats between the two groups. Conclusions In the reward conditioned reflex test, red,yellow and blue light stimuli have similar reward prediction effect. When stimulated with the same light, the time of stimulation has an impact on the learning ability of the rats,and an appropriate extension of stimulation is beneficial to the formation of conditioned reflex in them. The day/night training has no effect on the learning and memory ability of the rats.
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Objective The aim of this experiment was to study the improving effects of a ginsenoside hydrolysis product DS-1227 on scopolamine-induced learning and memory impairment in mice.Methods Sixty healthy 5-6-week old male ICR mice (body weight 22 ±2 g) were randomly divided into control group, model group, three DS-1227 groups (25 mg/kg, 50 mg/kg, 100 mg/kg), and positive control group (0.3 mg/kg).Fourteen days after oral administration of DS-1227, an open-field test was conduct to determine the mouse locomotor activity.Fifteen days after oral administration of DS-1227, all experimental animals were intraperitoneally administered scopolamine (0.75 mg/kg) and the mice of control group received the same volume of saline.In addition to scopolamine, the mice of positive control group received intraperitoneal injection of physostigmine in a dose of 0.3 mg/kg.Twenty minutes after completion of all the drug administration, object recognition test and Morris water maze test were conducted to evaluate the learning and memory abilities of the mice.Results DS-1227 had no significant effect on locomotor activity of the mice.Scopolamine obviously decreased the discrimination indexes in object recognition test, and prolonged the escape latency of water maze place navigation test.While 25 mg/kg, 50 mg/kg, 100 mg/kg of DS-1227 increased the discrimination indexes and decreased the escape latency of place navigation in the mice.Conclusion DS-1227 can improve the learning and memory impairment induced by scopolamine in mice.
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Objective To study the effects of dammarane sapogenins ( DS-1226 ) on sleep interruption-induced learning and memory impairment in mice.Methods 130 SPF healthy 5 -6-week old male ICR mice were randomly divided into control, model, DS-1226 low dose, DS-1226 medium dose and DS-1226 high dose groups.The behavioral alterations in open field (OF), Morris water maze (MWM) and step-through (ST) tests were detected at 15 days after rotating drum-induced sleep interruption ( SI) .Results The total distance, movement speed, total duration of movement were increased in OF test ( P<0.05, vs.the model group) after treatment.The latency of place navigation was increased from day 5 in the MWM test after 15 d sleep interruption, and the number of crossing in the target quadrant and the percent distance in target quadrant were decreased after 15 d sleep interruption ( P <0.05, vs.the control group), while the latency of place navigation was decreased, and the percent distance in target quadrant and percent time in target quadrant after high dose DS-1226 oral administration ( P<0.05, vs.the model group) were increased.Error times, distance in dark chamber, time in dark chamber and immobility time in dark chamber were increased in training of step through test ( P<0.05, vs.the control group);while these indexes were decreased after DS-1226 oral administration ( P<0.05, vs.the model group) .But there was no significant difference in the step through testing course.Conclusions The results show that orally administrated DS-1226 can ameliorate SI-induced learning and memory impairment, and there is a significant dosage-effect relationship.