The present study aimed at investigating the effects of chronic multiple stress on learning and memory functions of rats. Adult male Wistar rats were randomly divided into stressed and control groups. Rats in the stressed group were irregularly and alternately exposed to the situation of vertical revolution, sleep deprivation, noise stimulation, and night illumination 6 h per day for 6 weeks to prepare a chronic multiple stressed model. Learning and memory performance of rats was measured by using Morris water maze first and Y-maze afterwards. Neurons in the dentate gyrus(DG), CA3 and CA1 regions of the hippocampus were stained by using Cresyl violet method and counted. The results showed that: (1) After chronic multiple stress, compared with the control rats, the escape latency to the hidden platform in Morris water maze was significantly shortened in stressed rats. In stressed and control groups, the escape latency periods were (15.89+/-9.15) s and (27.30+/-12.51) s, respectively, indicating that spatial memory of the stressed rats was stronger than that of the control ones. In brightness-darkness discrimination learning in the Y- maze, the correct trials and correct percentage of entering safe arm was remarkably increased in the stressed rats, the correct rates of stressed and control groups were (79.01+/-1.23)% and (66.12+/-1.61)%, respectively, indicating that brightness-darkness discrimination learning ability of the stressed rats was better than that of the control ones. (2) After chronic multiple stress, nerve cell density in DG, CA1 and CA3 of the hippocampus in stressed rats was higher than that of the control group, the cell densities in DG, CA1 and CA3 of the stressed and the control group were (223.78+/-26.52), (112.07+/-14.23) and (105.55+/-18.12) as well as (199.13+/-15.36), (92.89+/-13.69), and (89.02+/-15.77) respectively. These results suggest that the chronic multiple stress may enhance the capability of spatial memory and brightness-darkness discrimination learning of rats. Possible reasons for the chronic multiple stress-induced learning and memory enhancement of rats were also discussed.
Animals ; Hippocampus ; physiology ; Learning ; physiology ; Male ; Maze Learning ; Memory ; physiology ; Neuronal Plasticity ; physiology ; Rats ; Rats, Sprague-Dawley ; Spatial Behavior ; physiology ; Stress, Physiological ; physiopathology

OBJECTIVETo explore the changes in spatial learning performance and long-term potentiation (LTP) which is recognized as a component of the cellular basis of learning and memory in normal and lead-exposed rats after administration of melatonin (MT) for two months.

METHODSExperiment was performed in adult male Wistar rats (12 controls, 12 exposed to melatonin treatment, 10 exposed to lead and 10 exposed to lead and melatonin treatment). The lead-exposed rats received 0.2% lead acetate solution from their birth day while the control rats drank tap water. Melatonin (3 mg/kg) or vehicle was administered to the control and lead-exposed rats from the time of their weaning by gastric gavage each day for 60 days, depending on their groups. At the age of 81-90 days, all the animals were subjected to Morris water maze test and then used for extracellular recording of LTP in the dentate gyrus (DG) area of the hippocampus in vivo.

RESULTSLow dose of melatonin given from weaning for two months impaired LTP in the DG area of hippocampus and induced learning and memory deficit in the control rats. When melatonin was administered over a prolonged period to the lead-exposed rats, it exacerbated LTP impairment, learning and memory deficit induced by lead.

CONCLUSIONMelatonin is not suitable for normal and lead-exposed children.

Animals ; Female ; Lead ; toxicity ; Learning ; drug effects ; Long-Term Potentiation ; drug effects ; Male ; Maze Learning ; drug effects ; Melatonin ; administration & dosage ; toxicity ; Rats ; Spatial Behavior ; drug effects

OBJECTIVEFebrile seizure is a very common emergency in children. Although researchers home and abroad constantly pay close attention to studies on brain damage and lesion possibly caused by febrile seizure, studies of effects on motor, behavior, spatial learning and memory are relatively seldom. In our study, Sprague-Dawley rats were utilized for the purpose of the exploration of effects of febrile seizures on their motor, behavior, spatial learning and memory.

METHODSSixty 21-day-old male Sprague-Dawley rats, weighing (50 +/- 5) g were divided randomly and equally into febrile seizure group (FS), febrile control group (FG) and normal control group (NG). Febrile seizure animal model was induced by hyperthermal bath with 45 degrees C water. Febrile seizure was induced twice a day, thus ten times within five days in FS group. Rats of FG group were immersed in the same hyperthermal water for 2 minutes. Nothing special was performed on NG group. The abilities of motor and behavior of every rat in these 3 groups were tested in inclined plane test (IPT), overhanging test (OHT) and open field test (OFT) to show their varieties. Furthermore, Morris water maze was applied to evaluate the effects by febrile seizure on spatial learning and memory in rats during the place navigation test and spatial probe test.

RESULTSIn the present experiments, febrile seizures were altogether induced 192 times with the mean latency being (4.25 +/- 0.98) minutes and the mean duration being (1.06 +/- 0.59) minutes. The experiments confirmed that multiple febrile seizures could lead to decreases of abilities in all tests in which analysis of variance indicated that there were significant differences between febrile seizure group and the other two (P < 0.01). In inclined plane test, the turning ability of the rats was weakened. The mean turning time was (9.1 +/- 2.6) seconds for FS, (5.3 +/- 2.1) seconds for FG and (5.3 +/- 2.0) seconds for NG. In overhanging test, the overhanging time was shortened: (33.4 +/- 18.1) seconds for FS, (50.1 +/- 20.3) seconds for FG and (59.0 +/- 20.7) seconds for NG. In the open field test, the rats became less active with the scores (5.1 +/- 2.0) for FS, (10.4 +/- 3.0) for FG and (13.2 +/- 2.3) for NG. Meanwhile, the authors discovered the decreases of the abilities of spatial learning and memory in rats caused by febrile seizures many times. In the place navigation test, the mean escape latency for the rats' looking for hidden platform was prolonged; the efficiency of their search strategy decreased; the swimming time the animals spent in platform region decreased [(44.02 +/- 5.25) seconds for FS, (51.75 +/- 5.28) seconds for FG and (57.07 +/- 5.36) seconds for NG; analysis of variance, P < 0.01.]; the number of times they crossed the platform area decreased [(6.07 +/- 1.77) times for FS, (9.25 +/- 2.07) times for FG and (11.34 +/- 2.37) times for NG; analysis of variance, P < 0.01]; the percentage of their swimming time fell (36.68% for FS, 43.13% for FG and 47.56% for NG).

CONCLUSIONThe experiments confirmed that multiple febrile seizures could result in damage and lesion of motor, behavior, spatial learning and memory in rats.

Animals ; Male ; Maze Learning ; physiology ; Memory ; physiology ; Motor Activity ; physiology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Seizures, Febrile ; physiopathology ; Spatial Behavior ; physiology

To investigate the effect of treadmill running on the ability of learning in young rats, male Sprague-Dawley rats (5 weeks of age) were used for the experiment. Animals were randomly divided into the control and running groups (n=15 in each group). The rats in running group were made run on a motor-driven treadmill for 1 week at a speed of 2 m/min for the first 5 min, at a speed of 5 m/min for the next 5 min, then at a speed of 8 m/min for the last 20 min. Then the Morris water maze was used to observe learning and memory ability of rats in both groups. The tests consisted of place navigation and spatial probe test. We found that, in place navigation training, the latency of rats in running group was less than that in control group (P<0.05); and from the third training session on, there was significant difference between the rats in control and running groups in swimming velocity (P<0.01); furthermore, it was observed that the rats in running group had stronger motivation and more exact orientation in searching for platform, which could be indicated by the index of turn angle and angular velocity. In spatial probe test, there was no significant difference between the two groups in swimming velocity, percentage of swimming distance and frequency of crossing platform in D quadrant, where the platform situated (P>0.05). These findings suggest that low speed treadmill running can enhance the ability of learning in young rats.
Age Factors ; Animals ; Male ; Maze Learning ; physiology ; Memory ; physiology ; Physical Conditioning, Animal ; physiology ; Rats ; Rats, Sprague-Dawley ; Spatial Behavior ; physiology ; Swimming ; physiology

It is known that stimulation of the α(2A)-adrenoceptors (α(2A)-ARs) by the selective α(2A)-AR agonist guanfacine produces an important and beneficial influence on prefrontal cortical (PFC) cognitive functions such as spatial working memory and selective attention. However, it is unclear whether stimulation of the α(2A)-ARs has a similar effect on fear conditioning that involves the amygdala and hippocampus. Here, we show that systemically administered guanfacine significantly enhances spatial learning of rats in the Lashley maze: compared with controls, the rats treated with guanfacine required significantly fewer trials and made significantly fewer errors to reach learning criterion. However, guanfacine produced no effect on acquisition of contextual and auditory fear memories. The present study suggests that beneficial effect of α(2A)-AR stimulation is task-dependent: guanfacine improves spatial learning but not fear conditioning.
Adrenergic alpha-2 Receptor Agonists ; pharmacology ; Animals ; Behavior, Animal ; drug effects ; Conditioning (Psychology) ; drug effects ; Fear ; drug effects ; Guanfacine ; pharmacology ; Maze Learning ; drug effects ; Memory ; drug effects ; Rats ; Spatial Behavior ; drug effects

OBJECTIVETo investigate the effects of citicoline on spatial learning and memory of rats after focal cerebral ischemia.

METHODSThe rats were randomly divided into sham-operation group, ischemia control group and citicoline group. In the later two groups, focal cerebral ischemia model was established by introducing an intraluminal filament into the left middle cerebral artery, and citicoline (500 mg/kg) or 0.9% NaCl was administered intraperitoneally once a day for 2 weeks after the operation. The rats in the sham-operation group were not subjected to middle cerebral artery occlusion (MCAO) with intraluminal filament. The spatial learning and memory functions of the rats were evaluated by Morris water maze test 15 days after MCAO for 5 days.

RESULTSThe rats in ischemia control group exhibited serious spatial learning and memory deficits in both place navigation test and spatial probe test. In the former test, the mean escape latency of citicoline-treated rats were significantly shorter than that of ischemia control rats (P<0.01), and in the latter test significant diffidence was noted between citicoline and ischemia control groups in the percentage time spent in the former platform quadrant and frequency of crossing the former platform (P<0.05).

CONCLUSIONCiticoline can improve the spatial learning and memory function of rats after focal cerebral ischemia.

Animals ; Avoidance Learning ; drug effects ; Cytidine Diphosphate Choline ; pharmacology ; Infarction, Middle Cerebral Artery ; physiopathology ; Male ; Maze Learning ; drug effects ; Nootropic Agents ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Spatial Behavior ; drug effects

Vacuolar protein sorting-associated protein 13B (VPS13B), also known as COH1, is one of the VPS13 family members which is involved in transmembrane transport, Golgi integrity, and neuritogenesis. Mutations in the VPS13B gene are associated with Cohen syndrome and other cognitive disorders such as intellectual disabilities and autism spectrum disorder (ASD). However, the patho-physiology of VPS13B-associated cognitive deficits is unclear, in part, due to the lack of animal models. Here, we generated a Vps13b exon 2 deletion mutant mouse and analyzed the behavioral phenotypes. We found that Vps13b mutant mice showed reduced activity in open field test and significantly shorter latency to fall in the rotarod test, suggesting that the mutants have motor deficits. In addition, we found that Vps13b mutant mice showed deficits in spatial learning in the hidden platform version of the Morris water maze. The Vps13b mutant mice were normal in other behaviors such as anxiety-like behaviors, working memory and social behaviors. Our results suggest that Vps13b mutant mice may recapitulate key clinical symptoms in Cohen syndrome such as intellectual disability and hypotonia. Vps13b mutant mice may serve as a useful model to investigate the pathophysiology of VPS13B-associated disorders.
Animals ; Autism Spectrum Disorder ; Cognition Disorders ; Exons ; Humans ; Intellectual Disability ; Learning Disorders ; Memory, Short-Term ; Mice ; Models, Animal ; Muscle Hypotonia ; Phenotype ; Rotarod Performance Test ; Social Behavior ; Spatial Learning ; Water

OBJECTIVE: To study the effects of ketamine and alcohol on learning and memory in mice and its possible mechanism. METHODS: Forty mice were divided into 4 groups: normal control group, ketamine group, alcohol group, and alcohol plus ketamine group. Ketamine and alcohol were given by intraperitoneal injection and intragastric administration, respectively, 1 time per day, for 14 days. The ability of learning and memory in mice was tested by the method of step-down and Morris water maze. Acetylcholine (ACh) and 5-hydroxy tryptamine(5-HT) in mice brain tissue were analyzed for the possible mechanism. RESULTS: (1) Step-down: The treatment groups lessened the latency and added wrong times (P < 0.05). The number of errors in the combined treatment group significantly increased comparing with the single drug treatment group (P < 0.05). (2) Morris water-maze: The treatment groups prolonged the latency (P < 0.05), reduced the target quadrant activity time significantly (P < 0.05), and decreased the numbers of crossing the former platform significantly (P < 0.05). (3) Biochemical index determination: The concentrations of ACh and 5-HT in treatment groups decreased significantly (P < 0.05), showed a more decreasement comparing with the single drug treatment group. CONCLUSION Ketamine has a synergistic effect with alcohol on learning and memory impairment in mice, which may be related to the common inhibitive effect on the ACh and 5-HT.
Acetylcholine/metabolism* ; Alcohols/pharmacology* ; Animals ; Brain/physiopathology* ; Drug Synergism ; Ketamine/pharmacology* ; Male ; Maze Learning/drug effects* ; Memory/drug effects* ; Memory Disorders/physiopathology* ; Mice ; Mice, Inbred ICR ; Serotonin/metabolism* ; Spatial Behavior/drug effects*

OBJECTIVETo investigate the effect of GEPT extracts on spatial learning ability of the APPV717I transgenic mice at the early stage of dementia and its possible mechanism.

METHODThirty APPV717I transgenic mice were randomly divided into three GEPT groups by intragastric administration at doses of 0.075, 0.15, 0.3 g x kg(-1) x d(-1), and a donepezil group by intragastric administration of 0.92 mg x kg(-1) x d(-1), a APPV717I transgenic model group and a normal group by intragastric administration of distilled water. A four-month treatment regimen with GEPT extracts was administered to APPV717I transgenic mice. Results showed that Spatial memory ability was measured in Morris water maze. The total area covered by shank1 and integral optical density in CA1 subfield within the hippocampus were determined using immunohistochemical stains and Image-Pro plus analysis. The ultrastructure of synapses in the hippocampal CA1 region was observed by electronic microscope.

RESULTAfter a four-month of GEPT treatment regimen, the mean escape latency period were significantly shortened (P < 0.05), and the target quadrant search time were significantly increased (P < 0.05) compared to the APPV717I transgenic model mice. There was a significant higher level in the expression of shank1 detected in the hippocampal CA1 area of APPV717I transgenic mice associated with an increase in the number of synapses treated with GEPT than the levels in the APPV717I transgenic model mice alone. The total area of positive cells covered by shank1 and their integral optical density in the hippocampal CA1 area of the APPV717I transgenic mice treated with GEPT were significantly increased more than those of the APPV717I transgenic model mice.

CONCLUSIONGEPT extracts can obviously improve the spatial memory ability of APPV717I transgenic mice at the early stage of dementia through enhancing the number of synapses and the expression of shank1, and this might lead to development of novel treatment therapies for the memory loss associated with AD.

Animals ; Dementia ; prevention & control ; Disease Models, Animal ; Female ; Learning ; Male ; Memory ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Mice, Transgenic ; Panax ; chemistry ; Plant Extracts ; therapeutic use ; Space Perception ; drug effects ; physiology ; Spatial Behavior ; drug effects ; physiology

PURPOSE: This ethnography was conducted to describe the meaning of illness of the elderly in traditional folk healing performance. METHOD: This study was guided by Klienman's explanatory model of health care systems. The fieldwork was conducted in an agricultural clan of Namwon City from January of 1990 to Feburary of 2001. Research data were collected by Ehnographic interview and participant observation. Participants of this study were 10 elders aged 74 years old to 96 years old; two of them were male. The data were analysed with the techniques of taxanomy, flow and decision, and proxemics. RESULT: The meaning of illness was categorized with four compononts, that is, ritual for life, defeat and failure in power game, humiliating punishment for guilt, and Tal. CONCULSION: These meanings were constructed on physical and socio-cultural environment of this clan. The healing strategies were determined based on the meanings of illness. These results can be used to understand the health behavior of the elderly and thus ensure the quality of nursing for the elderly.
Aged* ; Anthropology, Cultural ; Delivery of Health Care ; Guilt ; Health Behavior ; Humans ; Jeollabuk-do ; Male ; Nursing ; Punishment ; Spatial Behavior