OBJECTIVE: To illustrate the role of dehydrocorydaline (DHC) in chronic constriction injury (CCI)-induced neuropathic pain and the underlying mechanism. METHODS: C57BL/6J mice were randomly divided into 3 groups by using a random number table, including sham group (sham operation), CCI group [intrathecal injection of 10% dimethyl sulfoxide (DMSO)], and CCI+DHC group (intrathecal injection of DHC), 8 mice in each group. A CCI mouse model was conducted to induce neuropathic pain through ligating the right common sciatic nerve. On day 14 after CCI modeling or sham operation, mice were intrathecal injected with 5 µL of 10% DMSO or 10 mg/kg DHC (5 µL) into the 5th to 6th lumbar intervertebral space (L5-L6). Pregnant ICR mice were sacrificed for isolating primary spinal neurons on day 14 of embryo development for in vitro experiment. Pain behaviors were evaluated by measuring the paw withdrawal mechanical threshold (PWMT) of mice. Immunofluorescence was used to observe the activation of astrocytes and microglia in mouse spinal cord. Protein expressions of inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), phosphorylation of N-methyl-D-aspartate receptor subunit 2B (p-NR2B), and NR2B in the spinal cord or primary spinal neurons were detected by Western blot. RESULTS: In CCI-induced neuropathic pain model, mice presented significantly decreased PWMT, activation of glial cells, overexpressions of iNOS, TNF-α, IL-6, and higher p-NR2B/NR2B ratio in the spinal cord (P<0.05 or P<0.01), which were all reversed by a single intrathecal injection of DHC (P<0.05 or P<0.01). The p-NR2B/NR2B ratio in primary spinal neurons were also inhibited after DHC treatment (P<0.05). CONCLUSION An intrathecal injection of DHC relieved CCI-induced neuropathic pain in mice by inhibiting the neuroinflammation and neuron hyperactivity.
Animals ; Neuralgia/etiology* ; Mice, Inbred C57BL ; Analgesics/pharmacology* ; Neuroinflammatory Diseases/pathology* ; Constriction ; Male ; Receptors, N-Methyl-D-Aspartate/metabolism* ; Nitric Oxide Synthase Type II/metabolism* ; Mice, Inbred ICR ; Microglia/pathology* ; Spinal Cord/drug effects* ; Female ; Mice ; Tumor Necrosis Factor-alpha/metabolism* ; Disease Models, Animal ; Constriction, Pathologic/complications* ; Interleukin-6/metabolism* ; Astrocytes/metabolism* ; Chronic Disease ; Neurons/metabolism*

OBJECTIVES: To explore the therapeutic mechanism of Chaihu Shugan (CHSG) Decoction for improving cognitive impairment in rats with epilepsy induced by lithium chloride and pilocarpine. METHODS: Male SD rat models of cognitive impairment model after epilepsy induced by intraperitoneal injection with lithium chloride and pilocarpine were randomly divided into 5 groups (n=12) for treatment with daily gavage of saline, donepezil (90 mg/kg), or CHSG Decoction at 2.5, 5.0, 10, 20 and 40 g/kg for 4 consecutive weeks, with 10 rats with intraperitoneal injection with saline as the blank control group. Morris water maze test was used to evaluate cognitive and behavioral changes of the rats after treatment. The mRNA and protein expressions of ASIC1, NR1, NR2A and NR2B in the hippocampus of rats were detected using RT-qPCR and Western blotting. RESULTS: Compared with those with saline treatment, the rat models treated with CHSG Decoction at 5 and 10 g/kg showed significantly shortened escape latency and prolonged stay in the target quadrant with increased number of platform crossings in Morris water maze test. CHSG Decoction treatment at the two doses significantly increased ASIC1, NR1, NR2A and NR2B protein expressions in the hippocampus of the rat models, and their mRNA expression levels were all increased significantly after the treatment at the doses above 2.5 g/kg. CONCLUSIONS CHSG Decoction can improve cognitive impairment in rats after epilepsy possibly by regulating the expression and channel activity of NMDAR protein and its subunit protein via upregulating ASIC1 to modulate neuronal excitability and synaptic plasticity in the hippocampus.
Animals ; Hippocampus/drug effects* ; Receptors, N-Methyl-D-Aspartate/metabolism* ; Acid Sensing Ion Channels/metabolism* ; Rats, Sprague-Dawley ; Male ; Rats ; Epilepsy/complications* ; Cognitive Dysfunction/drug therapy* ; Drugs, Chinese Herbal/therapeutic use* ; Up-Regulation ; Maze Learning

Growth arrest DNA damage-inducible protein 45 β (GADD45B) has been reported to be a regulatory factor for active DNA demethylation and is implicated in the modulation of synaptic plasticity and chronic stress-related psychopathological processes. However, its precise role and mechanism of action in stress susceptibility remain elusive. In this study, we found a significant reduction in GADD45B expression specifically in the ventral, but not the dorsal hippocampal CA1 (dCA1) of stress-susceptible mice. Furthermore, we demonstrated that GADD45B negatively regulates susceptibility to social stress and NMDA receptor-dependent long-term potentiation (LTP) in the ventral hippocampal CA1 (vCA1). Importantly, through pharmacological inhibition using the NMDA receptor antagonist MK801, we provided further evidence supporting the hypothesis that GADD45B potentially modulates susceptibility to social stress by influencing NMDA receptor-mediated LTP. Collectively, these results suggested that modulation of NMDA receptor-mediated synaptic plasticity is a pivotal mechanism underlying the regulation of susceptibility to social stress by GADD45B.
Animals ; Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors* ; CA1 Region, Hippocampal/drug effects* ; Male ; Stress, Psychological/physiopathology* ; Mice ; Neuronal Plasticity/drug effects* ; Long-Term Potentiation/drug effects* ; Mice, Inbred C57BL ; Antigens, Differentiation/metabolism* ; Dizocilpine Maleate/pharmacology* ; Excitatory Amino Acid Antagonists/pharmacology* ; GADD45 Proteins

Chronic visceral pain is a persistent and debilitating condition arising from dysfunction or sensitization of the visceral organs and their associated nervous pathways. Increasing evidence suggests that imbalances in central nervous system function play an essential role in the progression of visceral pain, but the exact mechanisms underlying the neural circuitry and molecular targets remain largely unexplored. In the present study, the ventral tegmental area (VTA) was shown to mediate visceral pain in mice. Visceral pain stimulation increased c-Fos expression and Ca²⁺ activity of glutamatergic VTA neurons, and optogenetic modulation of glutamatergic VTA neurons altered visceral pain. In particular, the upregulation of NMDA receptor 2A (NR2A) subunits within the VTA resulted in visceral pain in mice. Administration of a selective NR2A inhibitor decreased the number of visceral pain-induced c-Fos positive neurons and attenuated visceral pain. Pharmacology combined with chemogenetics further demonstrated that glutamatergic VTA neurons regulated visceral pain behaviors based on NR2A. In summary, our findings demonstrated that the upregulation of NR2A in glutamatergic VTA neurons plays a critical role in visceral pain. These insights provide a foundation for further comprehension of the neural circuits and molecular targets involved in chronic visceral pain and may pave the way for targeted therapies in chronic visceral pain.
Animals ; Male ; Visceral Pain/metabolism* ; Up-Regulation/physiology* ; Ventral Tegmental Area/metabolism* ; Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors* ; Neurons/drug effects* ; Mice, Inbred C57BL ; Mice ; Proto-Oncogene Proteins c-fos/metabolism* ; Chronic Pain/metabolism* ; Glutamic Acid/metabolism*

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 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 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

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

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