Epilepsy is a chronic neurological disorder affecting ~65 million individuals worldwide. Abnormal synaptic plasticity is one of the most important pathological features of this condition. We investigated how ubiquitin-specific peptidase 47 (USP47) influences synaptic plasticity and its link to epilepsy. We found that USP47 enhanced excitatory postsynaptic transmission and increased the density of total dendritic spines and the proportion of mature dendritic spines. Furthermore, USP47 inhibited the degradation of the ubiquitinated α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunit glutamate receptor 1 (GluR1), which is associated with synaptic plasticity. In addition, elevated levels of USP47 were found in epileptic mice, and USP47 knockdown reduced the frequency and duration of seizure-like events and alleviated epileptic seizures. To summarize, we present a new mechanism whereby USP47 regulates excitatory postsynaptic plasticity through the inhibition of ubiquitinated GluR1 degradation. Modulating USP47 may offer a potential approach for controlling seizures and modifying disease progression in future therapeutic strategies.
Animals ; Receptors, AMPA/metabolism* ; Neuronal Plasticity/physiology* ; Seizures/physiopathology* ; Disease Models, Animal ; Mice, Inbred C57BL ; Mice ; Ubiquitin Thiolesterase/genetics* ; Male ; Excitatory Postsynaptic Potentials/physiology* ; Ubiquitination ; Dendritic Spines/metabolism* ; Hippocampus/metabolism*

OBJECTIVE: To explore the influence of electroacupuncture (EA) on the expression of AMPA receptor subunit GluR1 in the rats with acute spinal cord injury (SCI) and explore the potential effect mechanism of EA in treatment of acute SCI. METHODS: A total of 80 SD rats were randomly divided into five groups, i.e. a sham-operation group, a model group, an AMPA antagonist (DNQX) group, an EA group and a DNQX+EA group, 16 rats in each group. The modified Allen's impacting method was adopted to prepare the rat model of acute SCI at T RESULTS: Compared to the sham-operation group in 6 h, 24 h and 48 h after modeling, the BBB scores were all significantly decreased in the model group ( CONCLUSION The intervention with EA at "Dazhui" and "Mingmen" promotes the repair of the injured nerve in the spinal anterior horn probably through inhibiting GluR1 expression in the spinal injured area in the rats with acute SCI.
Animals ; Electroacupuncture ; Rats ; Rats, Sprague-Dawley ; Receptors, AMPA/genetics* ; Spinal Cord ; Spinal Cord Injuries/therapy*

OBJECTIVE: To explore the genetic basis for a family affected with mental retardation combined with autism. METHODS: For the family featuring X-linked recessive inheritance of mental retardation combined with autism, clinical data and peripheral blood samples were collected. Potential mutations of genes associated with intellectual impairment were sequenced with an Ion PGM platform. Suspected mutations were verified with a PCR-Sanger sequencing method. RESULTS: The patient with mental retardation had mild abnormal electroencephalograph(EEG), while brain MRI and CT scans showed no obvious abnormality. Two ABC (autism behavior checklist) testing scores were 73 and 66 when he was 7- and 13-year-old, respectively. A novel hemizygous mutation, c.64C>T (p.L22F), was detected in the GRIA3 gene in the patient, for which his mother was a heterozygous carrier. The mutation site was predicted to be possibly damaging and disease causing by PolyPhen_2 and MutationTaster. CONCLUSION The novel hemizygous c.64C>T (p.L22F) mutation of the GRIA3 gene probably underlies the phenotypes of mental retardation combined with autism in this family. Considering the variable clinical manifestation of mental retardation and genetic heterogeneity of autism, genetic testing is essential for making the correct diagnosis.
Adolescent ; Autistic Disorder ; genetics ; Child ; Humans ; Intellectual Disability ; genetics ; Male ; Mental Retardation, X-Linked ; genetics ; Mutation ; Receptors, AMPA ; genetics

OBJECTIVETo explore the clinical and genetic features of a Chinese boy featuring X-linked mental retardation.

METHODSClinical features of the patient were analyzed. The DNA of the patient and his parents was extracted and sequenced by next generation sequencing. The results were validated and analyzed with software.

RESULTSThe child displayed X-linked mental retardation. Sequencing showed the patient has carried a c.455T>C (p.L152P) mutation of the GRIA3 gene inherited from his mother.

CONCLUSIONThe c.455T>C (p.L152P) mutation of the GRIA3 gene probably underlies the X-linked mental retardation in this child.

Child, Preschool ; High-Throughput Nucleotide Sequencing ; methods ; Humans ; Male ; Mental Retardation, X-Linked ; genetics ; Mutation ; Receptors, AMPA ; genetics

OBJECTIVETo explore the effects of exposure to aluminum (Al) on long-term potentiation (LTP) and AMPA receptor subunits in rats in vivo.

METHODSDifferent dosages of aluminum-maltolate complex [Al(mal)3] were given to rats via acute intracerebroventricular (i.c.v.) injection and subchronic intraperitoneal (i.p.) injection. Following Al exposure, the hippocampal LTP were recorded by field potentiation technique in vivo and the expression of AMPAR subunit proteins (GluR1 and GluR2) in both total and membrane-enriched extracts from the CA1 area of rat hippocampus were detected by Western blot assay.

RESULTSAcute Al treatment produced dose-dependent suppression of LTP in the rat hippocampus and dose-dependent decreases of GluR1 and GluR2 in membrane extracts; however, no similar changes were found in the total cell extracts, which suggests decreased trafficking of AMPA receptor subunits from intracellular pools to synaptic sites in the hippocampus. The dose-dependent suppressive effects on LTP and the expression of AMPA receptor subunits both in the membrane and in total extracts were found after subchronic Al treatment, indicating a decrease in AMPA receptor subunit trafficking from intracellular pools to synaptic sites and an additional reduction in the expression of the subunits.

CONCLUSIONAl(mal)3 obviously and dose-dependently suppressed LTP in the rat hippocampal CA1 region in vivo, and this suppression may be related to both trafficking and decreases in the expression of AMPA receptor subunit proteins. However, the mechanisms underlying these observations need further investigation.

Aluminum ; toxicity ; Animals ; Down-Regulation ; drug effects ; genetics ; physiology ; Hippocampus ; drug effects ; physiology ; Long-Term Potentiation ; drug effects ; genetics ; physiology ; Male ; Protein Transport ; drug effects ; genetics ; physiology ; Random Allocation ; Rats ; Receptors, AMPA ; antagonists & inhibitors ; genetics ; metabolism ; Toxicity Tests, Acute ; Toxicity Tests, Subchronic

BACKGROUNDMonosodium L-glutamate (MSG) is a food flavour enhancer and its potential harmfulness to the heart remains controversial. We investigated whether MSG could induce cardiac arrhythmias and apoptosis via the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor.

METHODSMyocardial infarction (MI) was created by ligating the coronary artery and ventricular arrhythmias were monitored by electrocardiogram in the rat in vivo. Neonatal rat cardiomyocytes were isolated and cultured. Cell viability was estimated by 3-(4,5)-dimethylthiahiazo(-z-yl)-3,5-di-phenytetrazoliumromide (MTT) assay. Calcium mobilization was monitored by confocal microscopy. Cardiomyocyte apoptosis was evaluated by acridine orange staining, flow cytometry, DNA laddering, reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.

RESULTSMSG (i.v.) decreased the heart rate at 0.5 g/kg and serious bradycardia at 1.5 g/kg, but could not induce ventricular tachyarrhythmias in normal rats in vivo. In rats with acute MI in vivo, however, MSG (1.5 g/kg, i.v.) induced ventricular tachyarrhythmias and these arrhythmias could be prevented by blocking the AMPA and N-methyl-d-aspartate (NMDA) receptors. Selectively activating the AMPA or NMDA receptor induced ventricular tachyarrhythmias in MI rats. At the cellular level, AMPA induced calcium mobilization, oxidative stress, mitochondrial dysfunction and apoptosis in cultured cardiomyocytes, especially when the AMPA receptor desensitization were blocked by cyclothiazide. The above toxic cellular effects of AMPA were abolished by AMPA receptor blockade or by H2O2 scavengers.

CONCLUSIONSMSG induces bradycardia in normal rats, but triggers lethal tachyarrhythmias in myocardial infarcted rats probably by hindering AMPA receptors. AMPA receptor overstimulation also induces cardiomyocyte apoptosis, which may facilitate arrhythmia.

Animals ; Apoptosis ; drug effects ; Arrhythmias, Cardiac ; chemically induced ; Calcium ; metabolism ; Cell Survival ; drug effects ; Cells, Cultured ; DNA Fragmentation ; drug effects ; Glutamic Acid ; toxicity ; Male ; Microscopy, Confocal ; Myocardial Infarction ; chemically induced ; Rats ; Rats, Wistar ; Receptors, AMPA ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Sodium Glutamate ; toxicity ; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid ; toxicity

OBJECTIVETo study the effects of theanine on dopamine (DA), 5-hydroxy tryptamine (5-TH) and glutamate receptor 2 (GluR2) mRNA, phospholipase-γ1 (PLC-γ1) mRNA in cerebral ischemia-reperfusion injury rats and explore the mechanism of protective effects of theanine on the induced brain injury by ischemia-reperfusion in rats.

METHODSAccording to random number table, a total of 56 sprague-dawley rats in SPF grade about six-week old and 100 - 120 grams weighting were divided into five groups according to the body weight levels: model group (n = 12), sham-operation group (n = 8), low theanine group (10 mg/kg), middle theanine group (30 mg/kg) and high theanine group (90 mg/kg). There were 12 rats in each of the theanine group. The rats in model group and sham-operation groups were given distilled water, and the rats in theanine groups were given corresponding theanine solution intragastrically for fifteen days. Then the cerebral ischemia-reperfusion injury was established by middle cerebral artery occlusion (MCAO). The score of neurological behavior was evaluated at the 3rd and 24th hours after reperfusion. Rats were sacrificed at 24 hours after reperfusion, the concentrations of DA, 5-HT and theanine in rats brain following ischemia-reperfusion were determined. At the same time, we determined the levels of reactive oxygen species (ROS) and activities of catalase (CAT) in mitochondria of brain. The expressions of GluR2 mRNA and PLC-γ1 mRNA in rat brain were examined by reverse transcription polymerase chain reaction (RT-PCR) technique.

RESULTSThe score of neurological behavior of rats in model group, theanine-low, middle, high dose groups at the 3rd hour was 6.000 ± 0.926, 4.100 ± 0.738, 3.444 ± 0.726 and 2.250 ± 0.886 respectively (F = 29.70, P < 0.01), and the score at the 24th hour in these groups was 6.625 ± 0.916, 5.000 ± 0.817, 3.667 ± 0.707 and 2.625 ± 0.916 respectively(F = 34.68, P < 0.01). The concentration of DA in model group, theanine-low, middle, high dose groups and sham-operation group was (10.26 ± 1.12), (12.48 ± 1.09), (14.55 ± 0.94), (15.97 ± 0.92) and (11.98 ± 0.63) µg/g respectively (F = 43.76, P < 0.01). The concentration of 5-HT in these groups was (1.091 ± 0.160), (0.818 ± 0.101), (0.571 ± 0.050), (0.453 ± 0.111) and (0.863 ± 0.063) µg/g respectively (F = 48.68, P < 0.01). The level of ROS was (3.072 ± 0.503), (1.331 ± 0.268), (1.295 ± 0.061), (0.804 ± 0.200) and (2.158 ± 0.218) U×min⁻¹×mg⁻¹ (F = 80.82, P < 0.01) respectively and the activities of CAT in these groups were (4.880 ± 1.121), (8.405 ± 1.356), (9.535 ± 2.511), (15.090 ± 4.054) and (21.260 ± 6.054) U/g respectively (F = 28.58, P < 0.01). The expressions of GluR2 mRNA were 0.842 ± 0.020, 1.063 ± 0.100, 1.170 ± 0.152, 1.254 ± 0.131 and 1.012 ± 0.056 respectively (F = 9.23, P < 0.01). The expressions of PLC-γ1 mRNA in these groups were 0.737 ± 0.090, 0.887 ± 0.045, 0.963 ± 0.025, 0.991 ± 0.049 and 0.867 ± 0.079 respectively(F = 10.24, P < 0.01).

CONCLUSIONTheanine has a protective effect on the induced brain injury by ischemia-reperfusion in rats, which might be associated with its interaction with monoamine neurotransmitters and up-regulating the expressions of GluR2 mRNA and PLC-γ1 mRNA.

Animals ; Biogenic Monoamines ; metabolism ; Brain ; drug effects ; metabolism ; Brain Ischemia ; genetics ; metabolism ; Glutamates ; pharmacology ; Male ; Neurotransmitter Agents ; pharmacology ; Phospholipase C gamma ; genetics ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptors, AMPA ; genetics ; metabolism ; Reperfusion Injury ; genetics ; metabolism

OBJECTIVEThe present study aimed to test whether exposure to benzo(a)pyrene [B(a)P] affects spatial learning and short-term memory by modulating the expression of the Gria1 and Grin2a glutamate receptor subunit genes in the hippocampus.

METHODSThirty-six 21-24-day-old, male rats were randomly assigned into high-, medium-, and low-dose toxin exposure groups (6.25, 2.5, and 1 mg/kg, respectively) and a control group, each containing nine rats. The behavioral performance of adult rats exposed to sub-chronic administration of B(a)P was monitored by learning and memory tests (Morris water maze). Real-time PCR assays were used to quantify Gria1 and Grin2a gene expression in the hippocampus.

RESULTSAt medium and high doses, B(a)P impaired spatial learning performance. The crossing-platform-location frequency and the time spent swimming in the platform area, which both relate to short-term memory, were significantly decreased in B(a)P-treated rats compared with controls. The level of Gria1 mRNA increased 2.6-5.9-fold, and the level of Grin2a mRNA increased 10-14.5-fold, with a greater fold increase associated with higher doses of B(a)P.

CONCLUSIONWe demonstrated that sub-chronic administration of B(a)P inhibits spatial learning and short-term memory, and increases Gria1 and Grin2a expression in the hippocampus. This suggests a relationship of B(a)P exposure levels with Gria1 and Grin2a expression and impairment of short-term and spatial memory.

Animals ; Behavior, Animal ; drug effects ; Benzo(a)pyrene ; administration & dosage ; toxicity ; Dose-Response Relationship, Drug ; Drug Administration Schedule ; Gene Expression Regulation ; drug effects ; Hippocampus ; metabolism ; Learning ; drug effects ; Male ; RNA, Messenger ; genetics ; metabolism ; Rats ; Receptors, AMPA ; genetics ; metabolism ; Receptors, N-Methyl-D-Aspartate ; genetics ; metabolism

OBJECTIVETo study the effect of behavioral training on the learning and memory abilities and changes of NR2B and GluR1 expressions in the hippocampus of offspring rats with fetal growth retardation (FGR).

METHODSA FGR model was established in SD rats by passive smoking. The offspring rats were divided into FGR group and control group, each then randomized into training and untrained group. Morris water maze behavioral training was carried out in postnatal months 2 and 4, and the learning and memory abilities of the young rats were assessed using dark-avoidance test and step-down test. NR2B and GluR1 expression in the hippocampus of the rats were detected by immunohistochemistry.

RESULTSIn the dark-avoidance and step-down tests, the FGR rats showed deteriorated learning and memory performance in comparison with the control group, but behavioral training resulted in improved performance of the rats. The performance in FGR group was much improved after behavioral training, and the model factor and the training factor showed a significant interaction (P<0.05). The expression of NR2B and GluR1 in CA1 and CA3 regions of the hippocampus decreased in FGR group, then the their expressions in the CA1 region increased after training in both FGR and control groups, and the increment was especially obvious in GluR1 expression in the CA1 region at postnatal month 2. The two factors showed a significant interaction (P<0.05).

CONCLUSIONBehavioral training can improve the learning and memory abilities of FGR offspring rats, the mechanism of which is probably related to increased expression of NR2B and GluR1 in the CA1 region of the hippocampus.

Animals ; Animals, Newborn ; Avoidance Learning ; Behavior, Animal ; Female ; Fetal Growth Retardation ; chemically induced ; physiopathology ; Hippocampus ; metabolism ; Male ; Memory ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, AMPA ; genetics ; metabolism ; Receptors, N-Methyl-D-Aspartate ; genetics ; metabolism ; Tobacco Smoke Pollution

OBJECTIVETo study the expression of the AMPA receptor subunit glutamate receptor 2 (GluR2) and the cellular free calcium concentration in the white matter of neonatal rats with periventricular leukomalacia (PVL) and their roles in the pathogenesis of PVL.

METHODSA PVL model was prepared by unilateral carotid artery ligation (UCL) followed by exposure to 6% oxygen for 4 hrs in 2-day-old rats. The neonatal rats performed a sham operation, without hypoxia-ischemia (HI), were used as the control group. At 12, 24, 48 and 72 hrs of HI, the expressions of GluR2 mRNA and protein in the white matter were detected using real time quantitative PCR and Western blot respectively. Spectrophotofluorimetry and Fura 2/AM were used to detect the cellular free calcium concentration.

RESULTSThe expressions of GluR2 mRNA and protein in the white matter were significantly reduced in the PVL group at 24 hrs of HI, and remained at lower expressions until 72 hrs of HI compared with the control group (P < 0.05). The cellular free calcium concentrations increased significantly in the PVL group at 12 hrs of HI, and remained at higher levels until 72 hrs of HI compared with the control group (P < 0.05).

CONCLUSIONSThe expressions of GluR2 mRNA and protein in the white matter decreased whereas the cellular free calcium concentration increased in neonatal rats with PVL. The decreased expression of GluR2 might lead to the overloading of cellular calcium in the white matter, which may cause neuronal damage and death.

Animals ; Blotting, Western ; Calcium ; physiology ; Humans ; Infant, Newborn ; Leukomalacia, Periventricular ; etiology ; Oligodendroglia ; pathology ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Receptors, AMPA ; genetics ; physiology ; Reverse Transcriptase Polymerase Chain Reaction