ABSTRACT
@#To investigate the effects and possible molecular mechanism of S-oxiracetam(S-ORC) on learning and memory impairment in mice, mice were divided into 5 groups, control group, model group, high-dose of S-ORC (0.96 g/kg), medium-dose of S-ORC (0.48 g/kg) and low-dose of S-ORC (0.24 g/kg) treatment groups.Step-down test and Y-maze test were used to investigate the effects of S-ORC on the brain.The results of step-down test revealed that the mice in high and medium-dose groups could significantly decrease the reaction time, fault times and prolong the incubation periods of memory compared with the model group.Compared with the model group, the fault times of mice in high and medium-dose groups decreased significantly and the right times to find the safety increased significantly in Y-maze test.Furthermore, through treatment with S-ORC (high and medium-dose groups), the content of Ach in mice brain was significantly higher than that in model group, and the level of AChE decreased significantly.The above results suggest that the underlying mechanism of S-ORC on learning and memory impairment in mice may include the amelioration of the central cholinergic nervous system.
ABSTRACT
Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive brain stimulation technique that has been paid attention to with increasing interests as a therapeutic neural rehabilitative tool. Studies confirmed that high-frequency rTMS could improve the cognitive performance in behavioral test as well as the excitability of the neuron in animals. This study aimes to investigate the effects of rTMS on the cognition and neuronal excitability of Kunming mice during the natural aging. Twelve young mice, 12 adult mice, and 12 aged mice were used, and each age group were randomly divided into rTMS group and control group. rTMS-treated groups were subjected to high-frequency rTMS treatment for 15 days, and control groups were treated with sham stimulation for 15 days. Then, novel object recognition and step-down tests were performed to examine cognition of learning and memory. Whole-cell patch clamp technique was used to record and analyze resting membrane potential, action potential (AP), and related electrical properties of AP of hippocampal dentate gyrus (DG) granule neurons. Data analysis showed that cognition of mice and neuronal excitability of DG granule neurons were degenerated significantly as the age increased. Cognitive damage and degeneration of some electrical properties were alleviated under the condition of high-frequency rTMS. It may be one of the mechanisms of rTMS to alleviate cognitive damage and improve cognitive ability by changing the electrophysiological properties of DG granule neurons and increasing neuronal excitability.
ABSTRACT
OBJECTIVE To investigate the accumulated effect and the mechanism of repeated sc administration of acrylamide (AM) on learning and memory after 28 d,and the effect of AM on the amplitude of population spike(PS) potential after a single sc administration of AM. METHODS Female Wistar rats were sc adminstered with AM 10, 20 and 40 mg · kg-1 once a day for 28 d, and weighted every week. The ability of study and memory was evaluated, The morris water maze was used from 22nd to 28th day,followed by step down test on the 29th and 30th day. The escape latent period and the number of errors in those two days were recorded. Rats from normal control group and AM 40 mg·kg-1 group were taken to have their N-methyl-D-aspartate receptor (NR) and calmodulin-dependent protein kinaseⅡ (CaMKⅡ) protein levels detected by Western blotting. Additionally, some other female Wistar rats were sc administered with a single dose of AM 40 mg · kg-1 ,before the changes in PS potential amplitude induced by high frequency stimulation were recorded by long-term potential (LTP). RESULTS Compared with normal control group, the relative body mass gain was significantly decreased in AM exposure groups(P<0.01). Additionally, the escape latency period was significantly increased in AM 20 and 40 mg·kg-1 groups compared with normal control group, while the crossing frequency was not significantly different betmeen these four groups. Compared with the first day of step down test, the number of errors was significantly decreased(P<0.01) and the escape latency period was significantly extended(P<0.01) in normal control group on the 2nd day. However, the number of errors and the escape latency period did not significantly change in the AM groups between the two days. The results of Western blotting showed that the protein expressions and phosphorylation of NR2A and NR2B, as well as the phosphorylation of CaMKⅡ in AM 40 mg · kg-1 group were significantly increased compared with normal control group. LTP result showed that AM 40 mg·kg-1 significantly inhibited the amplitude of PS potential after a single percutaneous administration. CONCLUSION AM can inhibit the PS amplitude by inhibiting the release of glutamate, increasing the expressions and activities of NR,and inhibiting PS potential, thus affecting the hippocampal synaptic plasticity, and the function of learning and memory.
ABSTRACT
Objective: To investigate the protection of angelica polysaccharide (APS) on hippocampal neuron in rats with cerebral ischemia-reperfusion (I/R) injury. Methods: The model of cerebral I/R injury was established by suture method in rats. A total of 50 rats were randomly divided into five groups: Sham-operation, cerebral I/R injury, high-dose APS (200 mg/kg), mid-dose APS (100 mg/kg), and low-dose APS (50 mg/kg) groups. APS was ig administrated 3 d before operation. At 24 h after reperfusion, learning and memory function was detected by step down test, the apoptosis of hippocampal neuron was observed by terminal deoxylnucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL), and the expression of cleaved caspase-3, bcl-2, and bax in the hippocampus of rats was measured by enzyme-linked immunosorbent assay (ELISA). Results: Compared with those in the Sham-operation group, the learning and memory function was notably impaired in the I/R injury group, the number of errors increased. The apoptosis of hippocampal neuron increased and the expression of cleaved caspase-3, bcl-2, and bax in the hippocampus remarkably increased in the I/R injury group. The APS could significantly improve the learning and memory function of rats with the cerebral I/R injury and remarkably delay the decrease of the number of errors and the decrease of the apoptosis rate in the hippocampus of rats with the cerebral I/R injury. And the APS could also cause a significant down-regulation of cleaved caspase-3 and bax expression, while up-regulation of bcl-2 expression in hippocampus of rats with the cerebral I/R injury. Conclusion: APS has a neuroprotection on rats with the cerebral I/R injury. The neuroprotective mechanism of APS may involve in the inhibition of the neuronal apoptosis.
ABSTRACT
Objective To investigate the effects of Kangpa bolus on behaviors, dopamine and its metabolites of striatum in animals with Parkinson' s disease (PD). Methods The mice models of muscle tremor and rigor were established to observe the antagonism of Kangpa bolus. Step-down and step-through tests were used to evaluate the effects of Kangpa bolus on learning and memory function in mice. The rat model of PD was established to observe the effects of Kangpa bolus on rotation behaviors. The contents of DA and homovanillic acid( HVA) in the injured side of striatum were detected by ELISA. Results Compared with model group(723. 1 ±79.3) s,the duration of tremor in mice shortened significantly (P < 0. 01) in Kangpa bolus high dose and middle dose group ((548.0±27.0)s,(590.9 ±28.7)s). Compared with model group(3194.5 ±251.7)s,the duration of rigor in mice shortened significantly(P<0.01) in Kangpa bolus all dose group((2300.1 ±352.5)s,(2478.2 ±276.6)s, (2559.3 ±207.6) s). In step-down test, compared with model group (3. 10 ±0.74), the number of errors decreased significantly(P<0.01) in Kangpa bolus high dose and middle dose group (1.60 ±0. 97,1. 80 ±0.63). In step-through test, compared with model group( 2.30 ± 0. 68), the number of errors decreased significantly (P < 0.01) in Kangpa bolus high dose and middle dose group(0.80 ±0.79,1.10 ±0.74). Compared with model group (340.6 ±18.8) , the number of rotations of PD rats in thirty minutes reduced significantly (P< 0.01) in Kangpa bolus high dose and middle dose group(286.5 ± 12.1,296.6 ± 12.7) after three weeks treatment. Compared with model group(9.43 ±1.79,0. 87 ±0.12) nmol/L,the contents of DA and HVA in the injured side of striatum increased significantly(P<0. 01 ) in Kangpa bolus high dose( 18. 9 ±4. 01,1. 50 ± 1. 39) nmol/L and middle dose group (17.3±3.01,1.39±0.53)nmol/L Conclusion Kangpa bolus has some therapeutic effects on the animals of PD.
ABSTRACT
Objective To study the effects of light on body weight,learning and memory of mice.Methods Fifty mice aged 20 days were randomly assigned to one of the five groups: 200 W light group,100 W light group,60 W light group,40 W light group and normal control group,with 10 in each.They were exposed to different intensities of light 8 hours per day for 1 week.Then we monitored their body weight,examined the mean latency and inaccuracy number in step-down test,and examined the mean latency using a Morris' water maze to observe the effect of light pollution on the mice's learning and memory.Results Compared with the other four groups,there were significant decelerations of body weight increase in 200 W light group.No significant difference in body weight gain was found among the other four groups.The four light-treatment groups had no significant differences from control group in the mean latency,inaccuracy number in step-down test or the mean latency,or the mean crosses to the target in the Morris' water maze.Conclusion Short time high-intensity light can inhibit body weight increase in mice,but short-time light has no effect on the learning and memory of mice.
ABSTRACT
Aim To investigate the relationship between amnestic effect of ketamine,propofol or sodium oxybate and NMDA receptor.Methods Amnestic model was established by intraperitoneal injection of ketamine (20 mg?kg~-1),propofol(10 mg?kg~-1) or sodium oxybate(100 mg?kg~-1) respectively in mice before intracerebroventricular injection of NMDA,and then the error times,step down latency and step through latency were observed in the step down test and step through test.Results NMDA by intracerebroventricular injection decreased the error times and increased the step down latency and step through latency of amnestic mice induced by ketamine.It had no significant impact on those of amnestic mice induced by propofol or sodium oxybate.Conclusion NMDA receptor may be an important target for amnestic effect of ketamine,rather than the target for amnestic effect of propofol or sodium oxybate.
ABSTRACT
Aim To investigate the relationship between amnestic effect of enflurane or isoflurane and NMDA receptor.Methods Amnestic model was established by intraperitoneal injection of enflurane(0.4 ml?kg-1)or isoflurane(0.3 ml?kg-1)respectively in mice before intracerebroventricular injection of different doses of NMDA(25,50,75 ng),then the error times,step down latency and step through latency were observed in the step down test and step through test.Results NMDA(50,75 ng)by intracerebroventricular injection could decrease the error times,and increase the step down latency and step through latency of amnestic mice induced by enflurane or isoflurane in the step down test and step through test.Conclusions NMDA by intracerebroventricular injection can improve amnestic effect of enflurane or isoflurane partially.NMDA receptor may be an important target for amnestic effect of enflurane or isoflurane.
ABSTRACT
Aim To investigate the relationship between GABAA receptor or NMDA receptor and the amnestic effect induced by etomidate.Methods Amnestic model was established by intraperitoneal injection of etomidate(3 mg?kg-1) in mice before intracerebroventricular injection of different doses of bicuculline or NMDA,then the error times,step down latency and step through latency were observed and recorded in the step down test and step through test.Results Bicuculline(2,4 ?g) instead of NMDA by intracerebroventricular injection could decrease the error times and increase the step down latency and step through latency of amnestic mice in the step down test and step through test.Conclusion GABAA receptor rather than NMDA receptor may be an important target for the amnestic effect induced by etomidate.
ABSTRACT
Aim To investigate the relationship between neuronal nicotinic acetylcholine receptor and the amnesia and hypnosis induced by enflurane in mice.Methods Animal models were established by Intraperitoneal injecting of enflurane(2.2 ml?kg-1 and 0.4 ml?kg-1).Artificial cerebrospinal fluid or different dose of nicotine were intracerebroventricular injected,then sleeping time in the analeptic test was recorded;and the step down latency and error times in the step down test;step through latency and error times in the step through test.For the independent activity test,recorded the independent activity times of mice treated with enflurane(0.4 ml?kg-1) in 5 min.Results Compared with control group,intracerebroventricular nicotine decreased sleeping time in the analeptic test,increased step down latency and step through latency in both step down test and step through test.Furthermore,the error times were decreased in both tests.All the outcomes were significant and the influence was dose-dependent.There was no significant difference for the independent activity times of mice treated with 0.4 ml?kg-1 enflurane by ip injection.Conclusion All the evidence suggested that neuronal nicotinic receptor is one of important targets for the hypnotic and amnestic effect of enflurane in mice.
ABSTRACT
Aim To investigate the effects of maternal chronic aluminum exposure on memorial behaviour and hippocampal intracellular Ca2+ concentration ([Ca2+]i)on their offspring after the induction of LTP(long-term potentiation). Methods Adult Wistar rats (150~200 g) were exposed to aluminum by drinking distilled water, the concentration of AlCl3 is 0.015 mol?L-1(2 g?L-1) and 0.03 mol?L-1(4 g?L-1) aluminum chloride (AlCl3) solution, respectively, for 30 days prior to mating and during the whole gestation and suckling period. Their offspring were distributed into three experimental groups: control group; two exposed groups (represented by 0.2%-Al and 0.4%-Al ) administrated aluminum exposure ended at postnatal day 21. The brain tissue and blood aluminum levels were measured by Atomic absorption spectrometry (AAS). Memorial ability of the offspring was tested by Step down test.[Ca2+]i was measured by the technique of Fura-2/AM calcium ions fluorescence indicator. Results The mean aluminum content in blood and brain tissue was significantly higher than the control group(P0.05), but was significantly decreased in 0.4%-Al exposed group(P
ABSTRACT
AIM: To study the effects of 9 (4 Ethoxycarboxylyphenoxy) 6,7 dimethoxy 1,2,3,4 tetrahydro acridine (EDT) on learning and memory abilities. METHODS: The step down test and Y maze test were adopted in this study. RESULTS: EDT ( 2.5 , 5, 10 mg?kg -1 , ig? 5 d ) dose dependently improved the impairment of memory acquisition, memory consolidation and memory retrieval induced by scopolamine, NaNO 2 and alcohol in mice. CONCLUSION: EDT can improve learning and mermory ability in mice.
ABSTRACT
The effects of ?-carotene from Dunaliella salina(?-C) at three doses(12.5,25 and 50 mg?kg~(-1),ip) on learning and memory in rats and mice were studied by using step-down test and Y-maze test.In step-down tests,?-C at all three tested doses had significant effects on normal mice,and could remarkably antagonize the memory impairment induced by scopolamine and 20 % alcohol,but could not antagonize the impairment induced by sodium nitrite.As the same result,?-C at three tested doses administration had significant effects on rats in Y-maze tests.These results suggested that ?-C as an antioxidant could improve the ability of learning and memory in rats and mice.
ABSTRACT
The effects of compound oral fish oil preparation on the increase of intelligence were studied. Step-down test, normobaric hypoxia test and loaded swimming test in mice were used. The results indicated that during the administration period (15 d and 30 d), the oral preparation containing fish oil 3. 6 g/kg and 7. 2 g/kg increased both learning and memory abilities, promoted the tolerance of normal mice to hypoxia as well as swimming fatigue.
ABSTRACT
Objective To observe the effects of cistanchis glycosides on scopolamine -induced impariment of learning and memory and on sodium nitrite -induced impariment of learning and memo ry consolidation in mice.Methods Step down test was performed to reflect th e learning and memory of mice.Cistan chis glycosides were administered c onsecutive-ly for 30days.The mice were trained o n the 29th day and measurements were c arried out on the 30th day .Latent period and number of errors within 5min were noted.Scopolamine was given by intr aperitoneal injection 15min before train-ing,and sodium nitrite was administered subcutaneously right after trainin g.Results(1)Compared with model mice in-duced by scopolamine,cistanchis glycosides 200and 400mg /kg together with piracetam 600mg /k g considerably in-creased latent period and decreased error times.Cistanchis glycosides100mg /kg also increased latent time but decreased error times to some extent.(2)Compared with model mice induced by s odium nitrite,cistanchis glycosides 200and 400mg /kg increased latent time significantly but had no significant effect on the error times.Cistanchis glycosides 100mg /kg decreased latent time and error time s to some extent.Conclusion Cistanchis glycosides could obviou sly improve scopo-lamine -induced impariment of learn ing and memory and on sodium nitrite -induced impariment of learning and memory in mice.
ABSTRACT
OBJECTIVE:To observe the effect of the combination of propofol and midazolam on learning memory of mice.METHODS:Fifty mice were divided into 5 groups(n=10):NS group(normal saline,subcutaneously),LM group(10% intralipid,peritoneal),MZ group(1 mg?kg-1 midazolam,subcutaneously),PP group(20 mg?kg-1 propofol,peritoneal) and MP group(combination of 0.5 mg?kg-1 midazolam and 10 mg?kg-1 propofol).Latency and error times in each group were observed by step-down test and step-through test so as to evaluate the effect of medicine on learning memory of mice.RESULTS:On the 1st and 2nd day after medication,significant differences were noted in error times and latency in MP group,PP group and MZ group,as compared with NS group and LM group(P0.05).Compared with MZ group,reduction of error times and prolongation of latency were noted in MP group and PP group on the 2nd day after medication(P0.05).CONCLUSION:Combination of propofol and midazolam(half dose) can result in hypofunction of learning memory of mice as well as they are used alone.Synergistic action is performed between propofol and midazolam.