OBJECTIVETo compare brain lead accumulation and neurotoxicity induced by lead under drinking purified water and tap water on rat.

METHODSAll 104 male weaning SD rats were randomly divided into eight groups, matched-four pairs according to drinking water: tap water, purified water, tap water with lead 50 mg/L(lead acetate water-solution), purified water with lead 50 mg/L, tap water with lead 200 mg/L, purified water with lead 200 mg/L, tap water with lead 800 mg/L. All were fed with normal food and environmental cognitions kept consistent Morris water maze(including Place Navigation, Spatial Probe Test, Visible Platform Trial) was measured to test rat spatial learning at the 12 and 24 week. At the end of the experiment (28 week), rats were killed and the lead of brain and blood was measured by Graphite furnace atomic absorption spectrometric method; the NR1, NR2A, NR2B of NMDAR (N-methyl-D-aspartame receptor) in hippocampus were analyzed by RT-PCR.

RESULTSUnder the same lead exposure, no significant differences were observed in blood lead, however, brain lead level showed higher in drinking purified water group than that in tap water group. Expression of NR1, NR2A and NR2B in hippocampus of the rats drinking purified water was lower than those drinking tap water, especially at low lead exposure (50 mg/L) (P < 0.05). In the 24 week Morris water maze, place navigation test's escape latency showed significantly prolonged at the rats drinking purified water as compared with those drinking tap water on the pairs of 50 mg/L and 200 mg/L pb2+ groups (P < 0.05), and the differences occurred in early 1-2 days.

CONCLUSIONCompared with drinking tap water, drinking purified water might increase the accumulation of brain lead, lower NR1, NR2A, NR2B expression and delay the spatial learning and memory ability under chronic lead exposure in water.

Animals ; Drinking ; Intelligence ; drug effects ; Lead ; toxicity ; Male ; Maze Learning ; drug effects ; Memory ; drug effects ; N-Methylaspartate ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; drug effects

OBJECTIVETo study the receptor mechanism of anti-convulsant effect of Caoguo Zhimu Decoction (CZD).

METHODSSD rats in traditional Chinese medicinal (TCM) group were given CZD by gastrogavage for 24 days, while those in the control group were given normal saline of the same volume. The difference of convulsant threshold was compared between the TCM group and the control group induced by pentylenetetrazole. Changes of gamma-aminobutyric acid A receptor (GABAAR-alpha1 ) and N-methyl-D-aspartate receptor-NR1 (NMDAR-NR1 ) protein expression in hippocampus were quantitatively and orientatively measured by Western blotting and immunohistochemistry method. The changes of the two receptors were compared by receptor ligand binding assay.

RESULTSThe expression of GABAAR-alpha1 subunit in the TCM group was higher, but expression of NR1 subunit protein showed no significant difference when compared with those of the control group. The binding properties of GABAA receptor in the TCM group was obviously raised, but there was no obvious change in NMDA receptor.

CONCLUSIONThe anticonvulsant effect of CZD may be achieved by raising expression of GABAA R-alpha1 subunit, and enhancing its binding with ligand.

Animals ; Anticonvulsants ; pharmacology ; Drugs, Chinese Herbal ; pharmacology ; Hippocampus ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, GABA-A ; drug effects ; metabolism ; Receptors, N-Methyl-D-Aspartate ; drug effects ; metabolism

OBJECTIVETo explore material bases and neurobiological mechanisms of "Shen storing will" by observing learning and memory capacities and N-methyl-D-aspartic acid (NMDA) receptor expressions in Shen deficiency constitution (SDC) rats.

METHODSTotally 40 SD rats were randomly divided into the model group, the Zuogui Pill (ZP) group, the Yougui Pill (YP) group, the blank control group (consisting of normal pregnant rats), 10 in each group. SDC young rat model (inherent deficiency and postnatal malnutrition) was prepared by the classic way of "cat scaring rat". Medication started when they were scared by cat. Rats in the ZP group and the YP group were administered by gastrogavage with ZP suspension 0.1875 g/mL and YP suspension 0.0938 g/mL respectively. Equal volume of normal saline was administered to rats in the blank control group and the model group by gastrogavage. All medication was given once per day, 5 days in a week for 2 consecutive months. Learning and memory capacities were detected by Morris water maze test. Expressions of NMDA receptor subunits NR2A and NR2B in hippocamus were detected by immunohistochemical method.

RESULTSCompared with the blank control group, the latency period, total distance in Morris water maze test were longer in the model group (P < 0.05). All the aforesaid indices all decreased in the ZP group and the YP group, with statistical difference when compared with the model group (P < 0.05). The protein expressions of NR2A and NR2B in hippocamus were lower in the model group than in the blank control group (P < 0.05). But when compared with the model group, they were obviously higher in the ZP group and the YP group (P < 0.05).

CONCLUSIONSSDC rats had degenerated learning and memory capacities and lowered NMDA receptor expressions. ZP and YP could up-regulate learning and memory capacities and NMDA receptor expressions, thereby improving deterioration of brain functions in SDC rats.

Animals ; Drugs, Chinese Herbal ; pharmacology ; Female ; Learning ; drug effects ; Memory ; drug effects ; Pregnancy ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Up-Regulation

OBJECTIVETo estimate the effect of aluminum on hippocampal intracellular Ca²+ concentration and expression of phospholipase C (PLC) and NMDA receptor α (NMDARα) genes in hippocampus as well as the neural behaviors in weaning rats through subchronic exposure in order to explore the mechanism which aluminum impaired the ability of learning and memory of central nervous system development.

METHODSWeaning Wistar rats were randomly divided into four groups based on their body weight. Aluminium chloride was administered by water at the doses of 0.2%, 0.4% and 0.6% (m/v) for 90 days. Platform experiment was used to detect the activity of learning and memory. Fura-2/AM calcium ions fluorescence indicator was used to measure Ca²+ concentration in hippocampal neurons. Western blot method was used to detect the expressions of PLC and NMDARα genes.

RESULTSThe incubation of rats in platform experiment [(232.20 ± 57.45), (35.00 ± 9.37), (16.10 ± 5.57) s] shortened while increase of mistake times (1.10 ± 0.74, 2.20 ± 0.92, 3.40 ± 1.51) was significantly associated with the dose of aluminum (P < 0.01). The Ca(2+) concentration decreased significantly in the rats of aluminum exposed groups (P < 0.01). The expression of PLC and NMDARα in aluminum exposed groups (0.30 ± 0.06, 0.18 ± 0.04, 0.16 ± 0.03; 0.38 ± 0.03, 0.32 ± 0.02, 0.25 ± 0.02) decreased significantly compared with that in the control group (0.47 ± 0.07, 0.48 ± 0.04) (P < 0.01) and there was a dose-effect relationship in the NMDARα expression.

CONCLUSIONSubchronic exposure of aluminium could impair the ability of learning and memory in rats during development, inhibit the expression of NMDARα and PLC and reduce Ca²+ concentration, suggesting that the disorder of Ca²+ signaling system might be one of mechanisms of aluminium damaging the ability of learning and memory.

Aluminum ; toxicity ; Animals ; Calcium ; metabolism ; Hippocampus ; metabolism ; Learning ; drug effects ; Male ; Memory ; drug effects ; Rats ; Rats, Wistar ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Type C Phospholipases ; metabolism

Animals ; Catechin ; analogs & derivatives ; pharmacology ; Disease Models, Animal ; Fatigue ; metabolism ; physiopathology ; Learning ; drug effects ; Male ; Memory ; drug effects ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; metabolism

Animals ; Brain ; drug effects ; pathology ; Humans ; Hypothalamo-Hypophyseal System ; drug effects ; Neuroprotective Agents ; pharmacology ; Pituitary-Adrenal System ; drug effects ; Receptors, GABA-A ; drug effects ; Receptors, Glucocorticoid ; drug effects ; Receptors, N-Methyl-D-Aspartate ; drug effects ; Steroids ; pharmacology

OBJECTIVETo investigate the effects of aluminum on learning and memory and the expression of N-methyl-D-aspartic acid receptor (NMDAR) of hippocampus in offspring from female rats exposed to Al in the pregnancy or lactation, and to explore the mechanism of toxic effects of Al on central nervous system (CNS) during development.

METHODSThe pregnant Wistar rats were randomly divided into 3 groups based on their body weight, i.e. control group was exposed to distilled water, low exposure group (0.2%AlCl3) and high exposure group (0.4%AlCl3) were exposed orally to AlCl3 in pregnancy and lactation for 6 weeks, 10 rats each group. Aluminum content in blood and brains was determined by atomic absorption spectrophotometry (AAS). Platform experiment was used to detect the abilities of learning and memory. The expression levels of NMDARs were detected by western blot assay.

RESULTSThe Al content in blood and brains of rats in exposure groups increased significantly with Al dose, as compared with the control group (P < 0.05). In platform experiment, the incubation periods of rats in low and high exposure groups were (202.71 ± 81.99) and (19.67 ± 8.44) s respectively, which were significantly lower than that [(300.00 ± 0.00) s] in control group (P < 0.01), but the mistake times of rats in low and high exposure groups were 1.43 ± 0.85 and 2.47 ± 0.99 respectively, which were significantly higher than that (0.00 ± 0.00) in control group (P < 0.01). The Al exposure could change the proportion of NMDAR subtypes, the expression levels of NR1 and NR2B in hippocampus of newborn rats in low and high exposure groups were 25.22 ± 0.68, 81.23 ± 15.37 and 24.75 ± 0.71, 56.63 ± 7.82, respectively, which were significantly lower than those (31.69 ± 3.44, 107.61 ± 9.05) in control group (P < 0.05).

CONCLUSIONAluminum exposure in pregnancy and lactation could reduce the abilities of learning and memory in newborn rats, and change the proportion of NMDAR subtypes. The reduced NR1 and NR2B expression levels may be one of important mechanisms to influence the abilities of learning and memory in offspring.

Aluminum ; toxicity ; Animals ; Female ; Hippocampus ; drug effects ; metabolism ; Male ; Maze Learning ; Pregnancy ; Prenatal Exposure Delayed Effects ; metabolism ; Rats ; Rats, Wistar ; Receptors, N-Methyl-D-Aspartate ; metabolism

OBJECTIVETo study the involvement of excitatory amino acid system in astrocytes activation caused by dimethoate.

METHODSPure-cultured astrocytes were gained by three passages from primary cultured rat nerve cells, then treated with 10(-6),10(-5),10(-4) mol/L dimethoate for 48 h, 50 micromol/L and 100 micromol/L MK801, a NMDA receptor blocker, was used to intervene the effects induced by 10(-4) mol/L dimethoate. HPLC-FLD was utilized to measure the concentrations of excitatory amino acid (EAA), RT-PCR was used to detect the expression levels of NR2B, GLT-1, GLAST, GFAP and S100beta mRNA, and immunofluorescence staining method was applied to measure the expression levels of GFAP and S100beta proteins.

RESULTSThe expression levels of GLAST mRNA in all exposure groups were 67.8%, 68.6% and 76.2% of control level, respectively, which were significantly lower than that of control group (P < 0.05); The concentrations of EAA significantly decreased in 10(-4) mol/L dimethoate group, as compared with control group (P < 0.01); the expression levels of GFAP mRNA in 10(-4) mol/L dimethoate group, of S100beta mRNA in 10(-5) mol/L dimethoate group, of GFAP protein in 10(-4) mol/L and 10(-5) mol/L dimethoate groups and S100beta protein in 10(-4) mol/L dimethoate group were significantly higher than those in control group (P < 0.01). The expression levels of GLT-1 and GLAST mRNA in 10(-4) mol/L dimethoate plus 50 micromol/L or 100 micromol/L MK801 groups increased significantly, as compared with 10(-4) mol/L dimethoate group (P < 0.01), the expression levels of NR2B mRNA in 10(-4) mol/L dimethoate plus 50 micromol/L or 100 micromol/L MK801 groups increased significantly, as compared with control group (P < 0.05 or P < 0.01); the concentration of Glu in 10(-4) mol/L dimethoate plus 100 micromol/L MK801 group increased significantly, as compared with 10(-4) mol/L dimethoate group (P < 0.01); the expression levels of GFAP mRNA and protein in 10(-4) mol/L dimethoate plus 50 micromol/L or 100 micromol/L MK801 groups decreased significantly (P < 0.01); S100beta protein expression level in 50 micromol/L MK801 intervention group was significantly higher than thatl in control group (P < 0.01).

CONCLUSIONExcitatory amino acid system involved in astrocytes activation caused by dimethoate. MK801 was useful to control astrocytes gliosis.

Animals ; Astrocytes ; drug effects ; metabolism ; Cells, Cultured ; Dimethoate ; toxicity ; Dizocilpine Maleate ; pharmacology ; Excitatory Amino Acids ; metabolism ; Rats ; Receptors, N-Methyl-D-Aspartate ; antagonists & inhibitors

Alcohol-Related Disorders ; metabolism ; Animals ; Benzofurans ; pharmacology ; Glutamic Acid ; metabolism ; Hippocampus ; drug effects ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; metabolism

OBJECTIVETo understand the effects of moderate lead poisoning on the hippocampus tissue of rabbits in juvenile stage.

METHODSSixteen 45-day-old male New Zealand rabbits were randomly divided into blank group and lead-exposed group,8 for each group. Rabbits in the lead-exposed group were treated with 5 mg x kg(-1) x d(-1) lead acetate in their forage for 6 weeks to establish a moderate lead poisoning animal model. The blood lead levels and the lead contents in the hippocampus were determined by atomic absorption spectrometer and inductively coupled plasma-mass spectrometry respectively. Histopathology and ultra-microstructure in the hippocampus tissue were observed by light microscope and electron microscope. The NR1, NR2A and NR2B protein expressions in the CA1 hippocampal region were analyzed through immunohistochemical method.

RESULTSCompared with those of blank group, the blood lead levels of lead-exposed group were significant increased, (428.63 +/- 9.46) vs (66.38+/-3.93) microg/L (t = 100.08, P<0.01); and lead contents of hippocampus was significantly increased, (44.57+/-2.03) vs (21.20+/-1.53) ng/g, (t = 26.05, P<0.01); the hippocampus wet weight were significant decreased, (0.735 +/-0.012) vs (0.808+/-0.010), (t =12.97, P<0.01); the coefficient of hippocampus wet weight, was (0.458 +/-0.004) vs (0.476+/-0.005), (t =7.87, P<0.01). The significant declines in both the positive rate of NR1 and NR2A in the CA1 hippocampal region for NR1: (37.44 +/- 2.05)% vs (41.81+/-2.50)% (t = 3.82, P<0.01) and for NR2A: 21.97+/-1.08 vs 25.48+/-1.30 (t =5.89, P<0.01) were also observed. With light microscope and electron microscope, the histopathology and ultra-microstructure of neuron and glial cell in the hippocampus tissue were changed.

CONCLUSIONThe impairment of hippocampus of rabbits in juvenile stage with chronic moderate lead poisoning were observed, and the histopathology and N-methyl-D-aspartate receptor protein expressions in the hippocampus tissue were changed.

Animals ; Chronic Disease ; Disease Models, Animal ; Hippocampus ; drug effects ; metabolism ; pathology ; Lead Poisoning ; metabolism ; Male ; Rabbits ; Receptors, N-Methyl-D-Aspartate ; metabolism