Animals ; Humans ; Learning ; drug effects ; Memory ; drug effects ; Metals ; toxicity ; Nervous System ; drug effects

OBJECTIVETo explore the effect of tetramethylpyrazine on learning, memory, and cholinergic system in D-galactose-lesioned mice.

METHODSC57BL/6J mice were given subcutaneous injection of 2% D-galactose for 40 days (100 mg.kg-1.d-1). Normal saline, tetramethylpyrazine (TMP) and Huperzine A (HupA) were given respectively by intragastric administration in different study groups from the third week on. Learning and memory ability were tested by Morris water maze for 5 days at the sixth week. Acetylcholinesterase (AchE) activity, the binding sites (Bmax) and the affinity (KD) of M-cholinergic receptor were determined.

RESULTSThe learning and memory dysfunction, with lowered AchE activity and M-cholinergic receptor binding sites were found in the model group as compared with the normal control group. The tetramethylpyrazine, especially at the dose of 100 mg.kg-1.d-1, could markedly attenuate cognitive dysfunction, while elevate the lowered AchE activity (P < 0.05) and M-cholinergic receptor binding sites (P < 0.005) in the cerebral cortex of mice treated with D-galactose.

CONCLUSIONSThe tetramethylpyrazine can significantly improve central cholinergic system function, and thus enhance the learning and memory ability in D-galactose-lesioned mice.

Acetylcholinesterase ; metabolism ; Animals ; Avoidance Learning ; drug effects ; Cognition ; drug effects ; Galactose ; Learning ; drug effects ; Male ; Maze Learning ; drug effects ; Memory ; drug effects ; Mice ; Mice, Inbred C57BL ; Pyrazines ; pharmacology ; Receptor, Muscarinic M1 ; metabolism ; Receptors, Cholinergic ; drug effects ; physiology

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

OBJECTIVETo study the effects of quercetin, a flavonoid, on the learning and memory ability of 3-day-old neonatal rats with hypoxic-ischemic brain white matter damage (WMD).

METHODSSixty 3-day-old Sprague-Dawley rats were randomly divided into four groups: control, WMD model,and quercetin treatment groups (20 and 40 mg/kg). There were 15 rats in each group. Rats in the WMD model and the two quercetin treatment groups were subjected to right common carotid artery ligation followed by 2 hrs of exposure to 8% O2 to induce periventricular white matter injury. After the operation quercetin was administered daily in the two quercetin treatment groups for 6 weeks. Six weeks later, Morris water maze and open-field tests were carried out to test memory and learning ability as well as behavior and cognition.

RESULTSFrom the second day of training, escape latency in the Morris water maze test was more prolonged in the WMD model group than in the control group (P<0.01). The escape latency in the two quercetin treatment groups was shortened significantly compared with the WMD model group (P<0.05). The WMD model group crossed the original platform fewer times compared with the control and quercetin treatment groups (P<0.05). The open-field test indicated that the number of rearings increased and time spent in the centre was extended in the WMD model group compared with the control group. Compared with the WMD model group, the number of rearings was significantly reduced (P<0.05) and time spent in the centre was significantly shortened in the quercetin treatment groups (P<0.05).

CONCLUSIONSQuercetin treatment can improve memory and learning ability as well as cognitive ability in neonates with WMD, suggesting that quercetin protects against WMD resulting from hypoxia-ischemia.

Animals ; Hypoxia-Ischemia, Brain ; drug therapy ; psychology ; Learning ; drug effects ; Maze Learning ; drug effects ; Memory ; drug effects ; Quercetin ; pharmacology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the effect of nano-SiO2 on spatial learning and memory.

METHODSTwenty-four male rats were randomly divided into 3 groups: control group (C group), low dose group (L group) and high dose group (H group). The rats were intragastrically administrated with nanometer particles at 25 and 100 mg/kg body weight every day for 4 weeks. After exposure, the ability of learning and memory of rats was tested by Morris water maze, and electrophysiological brain stereotactic method was used to test long-tear potentiation (LTP) in dentate gyrus (DG) of the rats.

RESULTSThe increase rate of body weight in H group was reduced significantly compared with C group ( P < 0.05). In the space exploration experiment of Morris water maze test, the escape latency of H group was longer than that of C group (P < 0.05). The rats of H group spent less time in finding the target quadrant (P < 0.05) . The rate of LP induction of H group was significantly lower than that of C group (P < 0.05). After high fre quency stimulation (HFS), The changes of amplitude of population spike (PS) of L group and H group were lower than those of C group significantly (P < 0.05, P < 0.01).

CONCLUSIONNano-SiO₂may result in impairment of spatial learning and memory ability by reducing the rate of LTP induction and the increase of PS in hippocampus.

Animals ; Dentate Gyrus ; drug effects ; Long-Term Potentiation ; drug effects ; Male ; Maze Learning ; drug effects ; Memory ; drug effects ; Nanoparticles ; adverse effects ; Rats ; Silicon Dioxide ; adverse effects ; Spatial Learning ; drug effects

It is testified by long-standing traditional Chinese medicine clinical practice that ginseng was effective in treating dementia and promoting capability of learning and memory, for which ginsenoside Rg1 has been proved the main effective ingredient. Recently many researches have been carried out on the mechanism and action links of ginsenoside Rg1, and illustrated that it could exert the anti-dementia and nootropic effects through intervening multiple targets and links, thus to provide a theoretical basis for bettering the clinical use of ginsenoside Rg1.
Animals ; Ginsenosides ; pharmacology ; Humans ; Learning ; drug effects ; Memory ; drug effects ; Neuronal Plasticity ; drug effects ; Nootropic Agents ; pharmacology

In recent decades, scientists in Asian and Western countries have been paying great attention to ginseng research. Today, more than 200 ginsenosides and non-saponin constituents have been isolated and identified. Ginsenosides show biological activities only after being deglycosylated by intestinal bacteria. Aglycone protopanaxadiol and protopanaxatriol show the highest bioactivities. According to literature, the noticeable action of ginseng is that of delaying aging and especially increasing the nootropic effect, and it was found for the first time that Rg1 could increase hippocampal neurogenesis in vitro and in vivo under physiological and pathological circumstances. This is one of primary mechanisms underlying many of its pharmacological actions on the central nervous system. Rg1 was further shown to improve learning and memory in normal rats and mice. The nootropic signaling pathway has also been carried out in normal rats, and the Rg1-induced signaling pathway is similar to the memory formation that occurs in mammals, suggesting that Rg1 may have a potential effect in increasing intellectual capacity in normal people. Comparisons of chemical structures and pharmacologic functions between Panax ginseng and Panax quiquefolium were carried out by many scientists. The conclusion is that each has its own characteristics. There is no superiority or inferiority to the other.
Animals ; Cognition ; drug effects ; Ginsenosides ; pharmacology ; Humans ; Learning ; drug effects ; Memory ; drug effects ; Mice ; Neovascularization, Physiologic ; Neurogenesis ; Neuronal Plasticity ; drug effects ; Panax ; chemistry ; Rats ; Signal Transduction ; drug effects

OBJECTIVETo study the effects of prenatal exposure to benzo[a]pyrene (B[a]P) on the physical development, early behavioral development, the adaptability to new environment and the learning and memory ability of rat offspring.

METHODSPregnant rats were randomly divided into five groups: control group, olive oil group, 3 exposure groups (25, 50 and 100 mg/kg B [a]P). The rats were exposed to B [a]P) by intraperitoneal injection on the 17th-19th days during gestation. The offspring were weighed on postnatal days (PND)1, PND 4, PND 7 and PND 28, the indices of physical development, reflective ability and sensory function were detected for offspring, the Morris water maze and Open-field tests were used to measure the ability of learning and memory and the adaptability to new environment of offspring.

RESULTSThe time of ear opening in middle and high-dose groups [(4.1 +/- 0.4),(5.0 +/-0.4) d] was posterior to that in untreated and solvent groups [(3.3 +/- 0.5), (3.4 +/- 0.6) d ](P < 0.01). The attainment rate (6.5%) of the surface righting reflex test in high-dose group on the 4th day was significantly lower than that (36.1%) in untreated group, the attainment rate (50.0%) in high-dose group on PND7 was significantly lower than those (81.3% and 79.3%) in untreated group and solvent group (P < 0.05). Compared to the untreated group, the time of forelimb hanging test in all exposure groups on PND12 and PND14 significantly decreased; compared to the solvent group the time of forelimb hanging test decreased in high-dose group on the 14th day significantly decreased (P < 0.01). The attainment rate (61.9%) of olfactory discrimination in high-dose group on PND12 was significantly lower than that (94.3%) in untreated group (P < 0.05). The results of Morris water maze test showed that the escape latency of different dose groups significantly increased, and the time of spatial probe and the times of traversing flat in high-dose group decreased significantly, as compared to the untreated and solvent groups (P < 0.01). The results of open-field test indicated that the center retention time in middle and high-dose groups significantly prolonged, the times of crossing lattice obviously reduced, and the rearing times decreased in high-dose group, as compared to untreated (P < 0.05).Compared to the solvent group, the times of crossing lattice in all exposure groups reduced significantly (P < 0.01 or P < 0.05).

CONCLUSIONThe prenatal exposure to B[a]P could inhibit the physical development and early behavioral development, and influence the adaptability to new environment and learning and memory ability for offspring.

Animals ; Benzo(a)pyrene ; toxicity ; Female ; Learning ; drug effects ; Maze Learning ; Memory ; drug effects ; Motor Activity ; Neurotoxicity Syndromes ; physiopathology ; Pregnancy ; Prenatal Exposure Delayed Effects ; physiopathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effect of maternal brominated diphenyl ethers-209 (BDE-209) exposure on the learning and memory ability of the offspring rats in prenatal and lactational periods.

METHODSAfter confirmation of successful mating, female Wistar rats were randomized into 5 groups and subjected to daily oral gavage of peanut oil suspensions containing BDE-209 at the doses of 100 mg/kg (group A), 300 mg/kg (group B), 600 mg/kg (group C), and 1200 mg/kg (group D), or only peanut oil (group E, as control). From each group, 20 male weaning rats of the first generation were randomly selected to examine their learning and memorizing ability using Morris water maze. The histological alterations of the hippocampus were observed microscopically with HE staining after the test.

RESULTSDuring the initial one or two days of water maze test, no significant difference was noted in the escape latency between the groups (P=0.068, P=0.104). On days 3 to 5, groups B, C, and D showed prolonged escape latency as compared with the control group (P<0.05), but group A showed no such changes (P>0.05). Under optical microscope, the hippocampus in groups A and B exhibited no significant variation from that of the control group, but in groups C and D, the neural cells were obviously reduced and presented disorderly alignment, with substantial cell nuclear shrinkage and interstitial edema.

CONCLUSIONMaternal BDE-209 exposure induces disturbance of the learning and memorizing ability and pathological changes of the hippocampus in the offspring rats, and these changes show a dose-effect relation.

Animals ; Dose-Response Relationship, Drug ; Female ; Halogenated Diphenyl Ethers ; toxicity ; Hippocampus ; drug effects ; pathology ; Learning ; drug effects ; Male ; Maternal Exposure ; Maze Learning ; drug effects ; Memory ; drug effects ; Pregnancy ; Prenatal Exposure Delayed Effects ; Random Allocation ; Rats ; Rats, Wistar

Animals ; Brain Injuries ; drug therapy ; Gynostemma ; Learning ; drug effects ; Memory ; drug effects ; Phytotherapy ; Saponins ; pharmacology ; therapeutic use