Occupational exposure to 1-bromopropane (1-BP) induces learning and memory deficits. However, no therapeutic strategies are currently available. Accumulating evidence has suggested that N-methyl-D-aspartate receptors (NMDARs) and neuroinflammation are involved in the cognitive impairments in neurodegenerative diseases. In this study we aimed to investigate whether the noncompetitive NMDAR antagonist MK801 protects against 1-BP-induced cognitive dysfunction. Male Wistar rats were administered with MK801 (0.1 mg/kg) prior to 1-BP intoxication (800 mg/kg). Their cognitive performance was evaluated by the Morris water maze test. The brains of rats were dissected for biochemical, neuropathological, and immunological analyses. We found that the spatial learning and memory were significantly impaired in the 1-BP group, and this was associated with neurodegeneration in both the hippocampus (especially CA1 and CA3) and cortex. Besides, the protein levels of phosphorylated NMDARs were increased after 1-BP exposure. MK801 ameliorated the 1-BP-induced cognitive impairments and degeneration of neurons in the hippocampus and cortex. Mechanistically, MK801 abrogated the 1-BP-induced disruption of excitatory and inhibitory amino-acid balance and NMDAR abnormalities. Subsequently, MK801 inhibited the microglial activation and release of pro-inflammatory cytokines in 1-BP-treated rats. Our findings, for the first time, revealed that MK801 protected against 1-BP-induced cognitive dysfunction by ameliorating NMDAR function and blocking microglial activation, which might provide a potential target for the treatment of 1-BP poisoning.
Animals ; Brain ; drug effects ; metabolism ; pathology ; Cognitive Dysfunction ; drug therapy ; metabolism ; pathology ; Disease Models, Animal ; Dizocilpine Maleate ; pharmacology ; Excitatory Amino Acid Antagonists ; pharmacology ; Hydrocarbons, Brominated ; Inflammasomes ; drug effects ; metabolism ; Male ; Maze Learning ; drug effects ; physiology ; Microglia ; drug effects ; metabolism ; pathology ; NLR Family, Pyrin Domain-Containing 3 Protein ; metabolism ; Neurons ; drug effects ; metabolism ; pathology ; Nootropic Agents ; pharmacology ; Random Allocation ; Rats, Wistar ; Receptors, N-Methyl-D-Aspartate ; antagonists & inhibitors ; metabolism ; Spatial Memory ; drug effects ; physiology ; Specific Pathogen-Free Organisms

The aim of the present study was to observe whether dopamine receptor (DR) was involved in the effects of sodium salicylate (SS) on the expressions of N-methyl-D-aspartic acid (NMDA) and γ-aminobutyric acid (GABA) receptors in rat cochlear spiral ganglion neurons (SGNs). Forty-eight hours after primary culture of rat SGNs, immunofluorescence technique was applied to detect expressions of DR1 and DR2, the two subtypes of dopamine receptors. Western blot was performed to assess NMDA receptor NR1 subunit and GABAreceptor subunit α2 (GABRα2) protein expressions in the SGNs after the treatments of SS alone or in combination with DR antagonists. The results demonstrated that: (1) The DR1 and DR2 were expressed in the bodies and axons of the SGN; (2) After the treatment with SS, the surface protein expressions of GABRα2 and NR1 were decreased by 44.69% and 21.57%, respectively, while the total protein expressions showed no significant changes; (3) Neither SS + SCH23390 (DR1 antagonist) group nor SS + Eticlopride (DR2 antagonist) group showed significant differences in GABRα2 and NR1 surface protein expressions compared with the control group. These results suggest that SS regulates the surface GABAand NMDA receptors trafficking on SGN, and the mechanism may involve DR mediation.
Animals ; Benzazepines ; pharmacology ; Cells, Cultured ; Cochlea ; cytology ; Neurons ; drug effects ; Rats ; Receptors, Dopamine ; metabolism ; Receptors, GABA-A ; metabolism ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Sodium Salicylate ; toxicity ; Spiral Ganglion ; drug effects

OBJECTIVETo explore the neuroprotective effects of baicalin against hypoxia and glucose deprivation-reperfusion (OGD/RO)-induced injury in SH-SY5Y cells.

METHODSSH-SY5Y cells were divided into a control group, a OGD/RO group, which was subject to OGD/RO induction; and 3 baicalin groups subject to baicalin (1, 5, 25 μmol/L) for 2 h before induction of OGD/RO (low-, medium-, and high-dose baicalin groups). Cell viability was detected by thiazolyl blue tetrazolium bromide (MTT) assay and flow cytometric analysis was used to detect cell apoptosis. Real-time polymerase chain reaction was performed to determine the mRNA expression of caspase-3 gene. Western blot analysis was conducted to determine the expression of nuclear factor (NF)-κB and N-methyl-daspartic acid receptor-1 (NMDAR1).

RESULTSBaicalin could significantly attenuate OGD/RO mediated apoptotic cell death in SH-SY5Y cells; the apoptosis rates in the low-, medium- and high-dose groups were 12.1%, 7.9%, and 5.4%, respectively. Western blot and real-time PCR analysis revealed that significant decrease in caspase-3 expression in the baicalin group compared with the OGD/RO group (P<0.01). Additionally, down-regulation of NF-κB and NMDAR1 was observed in the baicalin group compared with those obtained from the OGD/RO group. Compared with the low-dose baicalin group, remarkable decrease was noted in the medium- and high-dose groups (P<0.01).

CONCLUSIONBaicalin pre-treatment attenuates brain ischemia reperfusion injury by suppressing cellular apoptosis.

Apoptosis ; drug effects ; Caspase 3 ; genetics ; metabolism ; Cell Death ; drug effects ; Cell Hypoxia ; drug effects ; Cell Line, Tumor ; Cell Survival ; drug effects ; Flavonoids ; pharmacology ; Glucose ; metabolism ; Humans ; NF-kappa B ; metabolism ; Nerve Tissue Proteins ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Real-Time Polymerase Chain Reaction ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Reperfusion

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

To observe the effect of Astragali Radix polysaccharides (APS) on the learning and memory functions of aged rats, in order to explore its mechanism for improving the learning and memory functions. Natural aging female SD rats were selected in the animal model and randomly divided into the control group, the APS low-dose group (50 mg x kg(-1)), the APS high-dose group (150 mg x kg(-1)) and the piracetam-treated group (560 mg x kg(-1)). They were orally administered with the corresponding drugs for consecutively 60 days. Besides, a young control group was set. The learning and memory functions of the rats were tested by the open-field test and the Morris water maze task. The Western-blot method was used to observe the levels of relevant neural plasticity protein N-methyl-D-aspartate receptor (NMDA receptor) in hippocampus, calcium/calmodulin dependent protein kinase II (CaMK II), protein kinase (PKA), the phosphorylation level of CAMP response element binding protein (CREB) and the protein expression of brain derived neurotrophic factor(BDNF). In this study, the authors found that the learning and memory functions and the hippocampus neural plasticity protein expression of the aged rat group were much lower than that of the young control group (P < 0.01). Compared with the aged rat group, the APS group showed the significant improvement in the impaired learning and memory functions of aged rats and the up-regulation in the hippocampus neural plasticity protein expression. The results showed that APS may improve the learning and memory functions of aged rats by increasing the expressions of relevant neural plasticity proteins.
Aging ; drug effects ; metabolism ; psychology ; Animals ; Astragalus Plant ; chemistry ; Brain-Derived Neurotrophic Factor ; metabolism ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; Female ; Hippocampus ; drug effects ; metabolism ; Humans ; Learning ; drug effects ; Memory ; drug effects ; Polysaccharides ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; 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

The present study was to investigate the role of the quinolinic acid (QUIN) and its relationship with N-methyl-D-aspartic acid (NMDA) receptor and metabotropic glutamate receptor 1 (mGluR1) in depression induced by chronic unpredictable mild stress (CUMS) in hippocampus. CUMS-induced depression model was established in Sprague-Dawley rats. Intrahippocampal injections of QUIN, QUIN antagonist Ro61-8048, non-competitive NMDA receptor antagonist MK-801 and mGluR1 antagonist AIDA were respectively adopted by rat brain stereotaxic coordinates. The behavioral observations were conducted by measurement of weight changes, sucrose preference test, open-field test and tail suspension test. The concentration of glutamic acid (Glu) and the expression of its receptor subunits in hippocampus were detected by HPLC and Western blot, respectively. The QUIN content in hippocampus was determined by enzyme linked immunosorbent assay (ELISA). The result showed that CUMS significantly induced the depressive-like behaviors in rats, increased the contents of QUIN and Glu, and upregulated the expression of NMDA receptor subunits NR2B and mGluR1 in hippocampus. Microinjection of QUIN into hippocampus resulted in animal depressive-like behaviors, and increased the content of Glu and the expression of NR2B and mGluR1 significantly. QUIN antagonist Ro61-8048 effectively restrained the depression-like behaviors induced by CUMS, and decreased the content of Glu and the expression of NR2B and mGluR1 significantly. Intrahippocampal injections of MK-801 and AIDA effectively improved the depression-like behaviors induced by CUMS and decreased the Glu content. The results suggest that CUMS may contribute to the production and release of QUIN in hippocampal microglia. QUIN results in elevation of Glu level via NMDA receptor and mGluR1, and the increase of expression of NR2B and mGluR1 in hippocampus, which leads to depression-like behaviors in the end.
Animals ; Behavior, Animal ; Depression ; drug therapy ; Dizocilpine Maleate ; pharmacology ; Glutamic Acid ; metabolism ; Hippocampus ; drug effects ; metabolism ; Quinolinic Acid ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, Metabotropic Glutamate ; metabolism ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Stress, Psychological

Schizophrenia, described as the worst disease affecting mankind, is a severe and disabling mental disorder. Schizophrenia is characterized by complicated symptoms and still lacks a diagnostic neuropathology, so developing schizophrenia animal models which have quantifiable measures tested in a similar fashion in both humans and animals will play a key role in new therapeutic approaches. According to the symptoms of cognitive impairment and emotional disorder, the N-methyl-d-aspartate (NMDA)-receptor antagonist MK-801 was applied to induce schizophrenia-like behavior in mice. Locomotor activity and prepulse inhibition (PPI) were selected as indices and the effect of clozapine was also investigated in this model. The results showed that compared with the normal group, MK-801-treated mice exhibited significantly increased locomotor activity and impaired PPI, and pre-exposure to clozapine could ameliorate the abnormality and make it back to normal level. These findings suggest that the model we established could be a useful tool for antipsychotic drug screening.
Animals ; Antipsychotic Agents ; pharmacology ; Clozapine ; pharmacology ; Disease Models, Animal ; Dizocilpine Maleate ; Inhibition (Psychology) ; Male ; Mice ; Motor Activity ; drug effects ; Receptors, N-Methyl-D-Aspartate ; antagonists & inhibitors ; Schizophrenia ; chemically induced ; physiopathology

UNLABELLEDOBJECTIVE To observe the changing laws of the protein expression of N-methyl D-aspartate receptor (NMDAR) in rat hippocampal subfields following focal ischemia/reperfusion injury, and to study the effects of sodium tanshinone B (STB) on it, thus exploring the possible mechanism of STB for treating cerebral ischemia.

METHODSThe rat model of focal cerebral ischemia/reperfusion injury was established using middle cerebral artery occlusion (MCAO) by reversibly inserting a nylon thread. The Wistar rats were randomly divided into the sham-operation group, the I/R model group, and the low, middle, and high dose STB groups. The neural functional disturbance was scored referring to the 5-grade Zea Longa EL standard. The protein expression of NMDAR1 in the ischemic side was detected using immunohistochemical assay.

RESULTSThere was statistical difference in the scores of the neural functional disturbance in the middle and high dose STB groups when compared with the model group (P < 0.01). Results of the immunohistochemical assay showed the expression of NMDAR1 in CA1 region was obviously higher in the I/R model group, the low and middle dose STB groups than in the sham-operation group (P < 0.01). The expression of NMDAR1 in CA1 region was obviously lower in the high dose STB group than in the I/R model group (P < 0.01), the low (P < 0.01) and middle dose STB groups (P < 0.05). The expression of NMDAR1 in CA3 region was obviously higher in the low dose STB group and the I/R model group than in the sham-operation group, the middle and high dose STB groups (P < 0.01). The expression of NMDAR1 in CA3 region was obviously higher in the high and middle dose STB groups than in the sham-operation group (P < 0.05).

CONCLUSIONSSTB could promote the recovery of neural functions in cerebral ischemia/reperfusion injury rats. STB fought against cerebral ischemia/reperfusion injury by lowering excitable neurotransmitter glumatic acid and reducing the protein expression of NMDAR1.

Animals ; Brain Ischemia ; metabolism ; Diterpenes, Abietane ; pharmacology ; Hippocampus ; drug effects ; metabolism ; Male ; Rats ; Rats, Wistar ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Reperfusion Injury ; metabolism

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