OBJECTIVETo explore the neuroprotection and the impact on brain development of lithium, the effects of lithium salt on the growth and survival of primary cultured cerebrocortical neurons were studied.

METHODSThe technique of primary cultured cerebrocortical neurons of newborn rats with serum-free medium was established, and the growth and survival of neurons treated with different doses of lithium chloride (0.625, 1.250, 2.500, 5.000, 10.000 mmol/L) were observed. The length of neuronal synapse, cell viability by MTT reduction assay were also measured.

RESULTSThe neurons were brighter, germinated rapidly, the neuronal synapse lengthened markedly, and the neurons viability was also better after treated with lithium chloride. Among the five doses, 5.000 mmol/L had the best effect [(53.80 +/- 5.84) micro m, P < 0.01].

CONCLUSIONLithium chloride can promote the growth and survival of neurons.

Animals ; Animals, Newborn ; Cell Division ; drug effects ; Cell Survival ; drug effects ; Cells, Cultured ; Cerebral Cortex ; cytology ; Lithium ; pharmacology ; Neurons ; cytology ; drug effects ; Neuroprotective Agents ; pharmacology ; Rats ; Rats, Wistar

OBJECTIVETo study the effects of 1-bromopropane (1-BP) on the functions of learning-memory and the central cholinergic system in rats.

METHODSForty male Wistar rats were randomly divided into four groups: low 1-BP group (200 mg/kg), middle 1-BP group (400 mg/kg), high 1-BP group (800 mg/kg) and control group, and the exposure time was 7 days. The Morris water maze (MWM) test was applied to evaluate the learning-memory function in rats. After the MWM test, the rats were sacrificed, the cerebral cortex and hippocampus were quickly dissected and homogenized in ice bath. The activity of acetylcholine esterase (AChE) and choline acetyltransferase (ChAT) in supernatant of homogenate were detected.

RESULTSThe latency and swim path-length of rats in middle and high 1-BP groups prolonged significantly in place navigation test and the efficiency of searching strategy obviously decreased, as compared with control group (P < 0.05 or P < 0.01). In spatial probe test, the number of crossing platform in three 1-BP groups decreased significantly, as compared with control group (P < 0.05 or P < 0.01). The cortical AChE activity of rats in middle and high 1-BP groups was significantly higher than that of control and low 1-BP group (P < 0.05 or P < 0.01). The AChE activity in rat hippocampus of high 1-BP group obviously increased, as compared with control group as compared with control group (P < 0.05). There was no significant difference of cortical ChAT activity between three 1-BP groups and control group (P > 0.05). In the hippocampus, there was no difference of ChAT activity among the groups (P > 0.05).

CONCLUSION1-BP exposure could significantly influence the learning-memory function in rats due to the increase of AChE activity.

Acetylcholinesterase ; metabolism ; Animals ; Cerebral Cortex ; drug effects ; enzymology ; Choline O-Acetyltransferase ; metabolism ; Hippocampus ; drug effects ; enzymology ; Hydrocarbons, Brominated ; toxicity ; Male ; Maze Learning ; drug effects ; Rats ; Rats, Wistar

Animals ; Cerebral Cortex ; drug effects ; physiology ; Epilepsy ; chemically induced ; physiopathology ; Female ; Flunarizine ; pharmacology ; Hippocampus ; drug effects ; physiology ; Male ; Penicillins ; adverse effects ; Rats ; Rats, Wistar

OBJECTIVETo investigate whether tri-ortho-cresyl phosphate (TOCP) and organophosphate compound that could produce organophosphate-induced delayed neuropathy (OPIDN) in hen and other sensitive species, directly affect oligodendrocytes, the myelin-forming cell of the central nervous system.

METHODSThis was achieved by a combination of measurements of cell viability (MTT) cell pathological observation in the presence and absence of the compound cultured hen brain oligodendrocytes were prepared and treated with various concentrations of TOCP.

RESULTSIn a time-course experiment TOCP showed a cytotoxic effect to oligodendrocytes and led to the oligodendrocyte processes disintegrated and membranous blebs, cytoplasmic vacuolation following exposure time of 24 h or longer, it showed a dose-depended and time-depended manner cytotoxic effect to oligodendrocytes at dose levels of 0.5 approximately 1.5 microg/ml (1.35 approximately 4.05 mol/L) concentrations of TOCP for 24 - 72 h exposure. MTT experiment indicated that TOCP inhibited cell viability by dose-depended manner at dose levels of 0.5 approximately 1.5 microg/ml (1.35 approximately 4.05 mol/L) concentrations of TOCP for an 24 h exposure.

CONCLUSIONSTOCP is cytotoxic to oligodendrocytes and leads to the oligodendrocyte processes disintegrated and membranous blebs, vacuolar degeneration, which suggests that this oligodendrocyte degeneration may involve in the pathogenesis mechanism for OPIDN.

Animals ; Cell Survival ; Cells, Cultured ; Cerebral Cortex ; pathology ; Chickens ; Dose-Response Relationship, Drug ; Oligodendroglia ; drug effects ; pathology ; Tritolyl Phosphates ; toxicity ; Vacuoles ; drug effects ; pathology

OBJECTIVETo investigate the change of free Ca(2+) in cytoplasma in the neurotoxicity of the manganese (Mn).

METHODSThe cortical neurons were separated from the neonatal Wistar rats and cultured in vitro. The neurons were grouped as the Mn-treated groups and the untreated group. The neurons in the Mn-added groups were incubated in the culture media containing lower, medium and high dosage manganese chloride (MnCl(2 x 4) H2O) with the concentration at 0.2, 0.6, 1.0 mmol/L respectively. Meanwhile, neurons in control were cultured in the normal culture media. All treatments stopped 24 h later. Neurons were labeled Ca(2+) sensitive prober, Fluo-3/AM. The fluorescence intensity of Fluo-3 combined with Ca(2+) was examined by LSCM (Laser scanning confocal microscope) and was treated by the picture analysis technique. The intensity was equal to the free Ca(2+) concentrations in cytoplasma of neurons.

RESULTSMnCl(2) can induce free Ca(2+) overloaded in cytoplasma of neurons, but the increasing degree varied in MnCl(2) dosage. Cytoplasma Ca(2+) concentration in the moderate dosage The moderate dosage MnCl(2) group and the high dosage MnCl(2) group were significantly higher than that in the lower dosage MnCl(2) group and the control group (P < 0.05).

CONCLUSIONThe Ca(2+) overload is involved in the neurotoxicity of manganese, and a dosage response relationship is found between the manganese chloride dose and Ca(2+) overload in cortical neurons.

Animals ; Animals, Newborn ; Calcium ; metabolism ; Cells, Cultured ; Cerebral Cortex ; drug effects ; metabolism ; Dose-Response Relationship, Drug ; Manganese ; toxicity ; Neurons ; drug effects ; metabolism ; Rats ; Rats, Wistar

OBJECTIVETo observe the influence of lead exposure on the activity of nitric oxide synthase (NOS) in different brain regions of rat.

METHODSBy establishing a series of rat models exposed to different low levels of lead (drinking water containing 0.025%, 0.050%, 0.075% of lead acetate) during developing period, NOS activities in hippocampus, cerebellum, cerebral cortex and brain stem were studied.

RESULTSOn the 21st day after birth, NOS activities in hippocampus of three levels of lead exposed groups [(1.53 +/- 0.20), (1.66 +/- 0.23), (1.88 +/- 0.32) U/mg pro respectively], and in cerebellum [(0.87 +/- 0.24), (0.85 +/- 0.09), (0.91 +/- 0.18) U/mg pro respectively] were significantly lower than those of control group [(2.36 +/- 0.18), (1.41 +/- 0.18) U/mg pro, respectively, P < 0.01]. NOS activities in cerebral cortex of 0.075% group [at 7, 14, 21 d of age [(1.29 +/- 0.14), (1.03 +/- 0.15), (0.69 +/- 0.10) U/mg pro] were significantly lower than those in control group [(2.54 +/- 0.31), (1.64 +/- 0.22), (1.24 +/- 0.14) U/mg pro respectively], and 0.025% group [(2.42 +/- 0.19), (1.59 +/- 0.17), (1.27 +/- 0.12) U/mg pro respectively], and 0.050% group [(2.56 +/- 0.53), (1.77 +/- 0.19), (1.24 +/- 0.10) U/mg pro respectively, P < 0.05]. There were no significant differences among control, 0.025%, and 0.050% groups (P > 0.05). Lead exposure had no influence on NOS activity in brain stem at the same age (P > 0.05).

CONCLUSIONNOS activities in hippocampus, cerebellum and cerebral cortex were inhibited by low level lead exposure and the degree of the effect was related to Pb exposure time and/or level of Pb exposed.

Animals ; Brain ; drug effects ; enzymology ; Brain Stem ; drug effects ; enzymology ; Cerebellum ; drug effects ; enzymology ; Cerebral Cortex ; drug effects ; enzymology ; Dose-Response Relationship, Drug ; Female ; Hippocampus ; drug effects ; enzymology ; Lead ; toxicity ; Nitric Oxide Synthase ; metabolism ; Rats ; Rats, Sprague-Dawley ; Time Factors

OBJECTIVETo investigate the effect of propofol on the expression of thrombospondin-1 (THBS-1) mRNA and protein in purified newborn rat cortical astrocytes in vitro.

METHODSAstrocytes were isolated from newborn rat cortex and grown in culture before exposure to propofol at 3, 10, 30, 100 or 300 µmol/L for 6 h, 12, or 24 h. The mRNA level of THBS-1 was detected by RT-PCR, and the protein level of THBS-1 was detected by immunofluorescence cytochemistry and Western blotting.

RESULTSPropofol exposure caused significantly upregulated THBS-1 level in cultured astrocytes (P<0.05) to a level about 1.3 times higher than that in control cells. The mRNA and protein levels of THBS-1 in cultured rat cortical astrocytes were upregulated by exposures to 10, 30 and 100 µmol/L propofol (P<0.01). High expression of THBS-1 mRNA and protein was detected in the cells with exposures for different durations (P<0.05), especially in the 12 h group (P<0.01).

CONCLUSIONPropofol at clinically relevant concentrations can modulate the level of THBS-1 secreted by astrocytes of rat cerebral cortex in vitro.

Animals ; Astrocytes ; drug effects ; metabolism ; Cells, Cultured ; Cerebral Cortex ; cytology ; Propofol ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Thrombospondin 1 ; metabolism

OBJECTIVETo observe the effect of different doses of acetamide on the histopathology in the cerebral cortex of rats with tetramine (TET) poisoning and to provide a basis for the treatment of fluoroacetamide poisoning with acetamide.

METHODSEighty clean Sprague-Dawley rats were randomly divided into five groups: saline control group,dimethylsulfoxide water solution control group,TET poisoning group, acetamide (2.88 g/kg/d) treatment group, and acetamide (5.68 g/kg/d) treatment group, with 16 rats in each group. Rats in the poisoning group and treatment groups were poisoned with TET by intragastric administration after fasting; then, saline was injected intramuscularly into rats of the poisoning group, and different doses of acetamide were injected intramuscularly into rats of treatment groups; the course of treatment was 5 d. At 3 h, 12 h, 48 h, and 7 d after treatment, the cerebral cortex was harvested from rats in each group, and the histopathological changes in the cerebral cortex were evaluated under light and electron microscopes.

RESULTSThe light microscopy showed that the TET poisoning group had hypoxia changes in the cerebral cortex, which worsened over time; the treatment groups had reduced hypoxia changes, and the acetamide (2.88 g/kg/d) treatment group had more reduction than the acetamide (5.68 g/kg/d) treatment group. The electron microscopy showed that the apoptosis of neuronal cells were the main pathological changes in the TET poisoning group; the treatment groups had reduced apoptotic changes, and the acetamide (2.88 g/kg/d) treatment group had more reduction than the acetamide (5.68 g/kg/d) treatment group.

CONCLUSIONNo pathological changes associated with the synergistic toxic effect of acetamide and TET are found in the cerebral cortex. Acetamide (2.88 g/kg/d) could reduce central nervous lesions, but the efficacy is not improved after increasing the dose. For patients who cannot be identified with TET or fluoroacetamide poisoning, acetamide could be considered for treatment.

Acetamides ; pharmacology ; Animals ; Bridged-Ring Compounds ; toxicity ; Cerebral Cortex ; drug effects ; pathology ; Disease Models, Animal ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To evaluate the accuracy of cerebral state index (CSI) as an indicator of anesthesia depth in patients in the induction of anesthesia with target-controlled infusion of propofol. METHODS: Forty ASA (American Society of Anesthesiologists) I approximately II patients scheduled for an operation under general anesthesia were anesthetized with target-controlled infusion of propofol. Target plasma concentration was 0. 5 mg/L at the beginning, and increased by 0. 5 mg/L every 5 minutes, till 5 minutes after the level of MOAA/S (modified observer's assessment of alertness/sedation) was 0. The CSI, mean arterial pressure (MAP), heart rate (HR), MOAA/S level, and the effect-site concentration of propofol were recorded. RESULTS: (1) CSI values declined with the decrease of MOAA/S levels. CSI values were statistically different between level 0 and 1, level 1 and 2, level 3 and 4, level 4 and 5 of MOAA/S (P < 0.05). The difference of MAP had statistical significance between level 3 and level 2 of MOAA/S (P < 0.05). HR values had no statistical difference between the two levels of MOAA/S (P > 0.05). (2) The spearman rank correlation co-efficients between CSI, MAP, HR and the level of MOAA/S were 0.929, 0.421, and 0.085, respectively. The prediction probabilities (Pk) to differentiate different levels of MOAA/S for CSI, MAP, and HR were 0.94, 0.67, and 0.54, respectively. (3) There was linear regression relationship between CSI and the effect-site concentration of propofol (the coefficient of determination R2 was 0. 833, P < 0.01). CONCLUSION During the induction of patients with target-controlled infusion of propofol, the CSI is accurate as an indicator of awakeness and different levels of consciousness after anesthesia, and can reliably predict the anesthesia depth.
Adjuvants, Anesthesia ; Adult ; Anesthesia, General ; Anesthetics, Intravenous ; Cerebral Cortex ; drug effects ; physiology ; Female ; Humans ; Male ; Monitoring, Intraoperative ; methods ; Propofol

OBJECTIVETo study the toxicity of methomyl to acetylcholinesterase (AChE) in different regions.

METHODSThe optimal temperature and time for measurement of AChE activity were determined in vitro. The dose- and time-response relationships of methomyl with AChE activity in human erythrocyte membrane, rat erythrocyte membrane, cortical synapses, cerebellar synapses, hippocampal synapses, and striatal synapses were evaluated. The half maximal inhibitory concentration (IC50) and bimolecular rate constant (K) of methomyl for AChE activity in different regions were calculated, and the type of inhibition of AChE activity by methomyl was determined.

RESULTSAChE achieved the maximum activity at 370 °C, and the optimal time to determine initial reaction velocity was 0-17 min. There were dose- and time-response relationships between methomyl and AChE activity in the erythrocyte membrane and various brain areas. The IC50 value of methomyl for AChE activity in human erythrocyte membrane was higher than that in rat erythrocyte membrane, while the Ki value of methomyl for AChE activity in rat erythrocyte membrane was higher than that in human erythrocyte membrane. Among synapses in various brain areas, the striatum had the highest IC50 value, followed by the cerebellum, cerebral cortex, and hippocampus, while the cerebral cortex had the highest Ki value, followed by the hippocampus, striatum, and cerebellum. Lineweaver-Burk diagram demonstrated that with increasing concentration of methomyl, the maximum reaction velocity (Vmax) of AChE decreased, and the Michaelis constant (Km) remained the same.

CONCLUSIONMethomyl is a reversible non-competitive inhibitor of AChE. AChE of rat erythrocyte membrane is more sensitive to methomyl than that of human erythrocyte membrane; the cerebral cortical synapses have the most sensitive AChE to methomyl among synapses in various brain areas.

Acetylcholinesterase ; metabolism ; Animals ; Cerebellum ; drug effects ; Cerebral Cortex ; drug effects ; Erythrocyte Membrane ; drug effects ; enzymology ; Hippocampus ; drug effects ; Humans ; Inhibitory Concentration 50 ; Methomyl ; toxicity ; Rats ; Synapses ; drug effects ; Toxicity Tests