Preclinical studies suggest that the GABA receptor is a potential target for treatment of substance use disorders. Baclofen (BLF), a prototypical GABA receptor agonist, is the only specific GABA receptor agonist available for application in clinical addiction treatment. The nucleus accumbens shell (AcbSh) is a key node in the circuit that controls reward-directed behavior. However, the relationship between GABA receptors in the AcbSh and memory reconsolidation was unclear. The aim of this study was to investigate the effect of intra-AcbSh injection of BLF on the reconsolidation of morphine reward memory. Male C57BL/6J mice were used to establish morphine conditioned place preference (CPP) model and carry out morphine reward memory retrieval and activation experiment. The effects of intra-AcbSh injection of BLF on morphine-induced CPP, reinstatement of CPP and locomotor activity were observed after environmental cues activating morphine reward memory. The results showed that intra-AcbSh injection of BLF (0.06 nmol/0.2 μL/side or 0.12 nmol/0.2 μL/side), rather than vehicle or BLF (0.01 nmol/0.2 μL/side), following morphine reward memory retrieval abolished morphine-induced CPP by disrupting its reconsolidation in mice. Moreover, this effect persisted for more than 14 days, which was not reversed by a morphine priming injection. Furthermore, intra-AcbSh injection of BLF without morphine reward memory retrieval had no effect on morphine-associated reward memory. Interestingly, administration of BLF into the AcbSh had no effect on the locomotor activity of mice during testing phase. Based on these results, we concluded that intra-AcbSh injection of BLF following morphine reward memory could erase morphine-induced CPP by disrupting its reconsolidation. Activating GABA receptor in AcbSh during drug memory reconsolidation may be a potential approach to prevent drug relapse.
Animals ; Baclofen ; administration & dosage ; Conditioning, Classical ; GABA-B Receptor Agonists ; administration & dosage ; Locomotion ; Male ; Memory ; Mice ; Mice, Inbred C57BL ; Morphine ; Nucleus Accumbens ; drug effects ; Opioid-Related Disorders ; Reward

OBJECTIVE: To investigate the molecular mechanisms of the adverse effects of exposure to sulfamonomethoxin (SMM) in pregnancy on the neurobehavioral development of male offspring. METHODS: Pregnant mice were randomly divided into four groups: control- (normal saline), low- [10 mg/(kg•day)], middle- [50 mg/(kg•day)], and high-dose [200 mg/(kg•day)] groups, which received SMM by gavage daily during gestational days 1-18. We measured the levels of short-chain fatty acids (SCFAs) in feces from dams and male pups. Furthermore, we analyzed the mRNA and protein levels of genes involved in the mammalian target of rapamycin (mTOR) pathway in the hippocampus of male pups by RT-PCR or Western blotting. RESULTS: Fecal SCFA concentrations were significantly decreased in dams. Moreover, the production of individual fecal SCFAs was unbalanced, with a tendency for an increased level of total fecal SCFAs in male pups on postnatal day (PND) 22 and 56. Furthermore, the phosphatidylinositol 3-kinase (PI3k)/protein kinase B (AKT)/mTOR or mTOR/ribosomal protein S6 kinase 1 (S6K1)/4EBP1 signaling pathway was continuously upregulated until PND 56 in male offspring. In addition, the expression of Sepiapterin Reductase (SPR), a potential target of mTOR, was inhibited. CONCLUSION In utero exposure to SMM, persistent upregulation of the hippocampal mTOR pathway related to dysfunction of the gut (SCFA)-brain axis may contribute to cognitive deficits in male offspring.
Alcohol Oxidoreductases ; metabolism ; Animals ; Anti-Infective Agents ; toxicity ; Fatty Acids, Volatile ; analysis ; Feces ; chemistry ; Female ; Hippocampus ; drug effects ; metabolism ; Male ; Memory ; drug effects ; Mice, Inbred ICR ; Pregnancy ; Prenatal Exposure Delayed Effects ; Sulfamonomethoxine ; toxicity ; TOR Serine-Threonine Kinases ; 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

OBJECTIVE: To investigate the effects of Acorus tatarinowii Schott and its active component 5- hydroxymethyl furfural (HMF) on learning and memory and ERK/CREB signal in hippocampus of rats with exercise-induced fatigue. METHODS: SD rats were randomly divided into normal group (A), exercise group (B), exercise + HMF low, middle and high dose treatment group (C, D, E), exercise + acorus tatarinowii Schott low, middle and high dose treatment group (F, G, H), with ten rats in each group. The rats in group C, D and E were treated with HMF at the doses of 0.10, 1.00 and 3.00 mg. kg by ig. The rats in group F, G and H were treated with the extracts of Acorus tatarinowii Schott at the doses of 0.12, 1.20 and 4.80 g. kg by ig. Learning and memory of rats were tested by the method of water maze experiment, and the expression levels of p-ERK1/2 and p-CREB protein in hippocampus of rats were tested by the method of Western blot in the end of the experiment. RESULTS: The escape latencies of E and H groups were lower than those of groups B, C, D, F and G; and the numbers of plateau crossing were more than those of groups B, C, D, F and G and the expression levels of p-ERK1/2, p-CREB protein were higher than those of groups B, C, D, F and G , respectively(P ＜ 0.01). There was no significant difference in the above indexes among groups A, E and H(P＞0.05) except that the expression levels of p-ERK2 protein in group E were lower than those in group A and H (P＜0.05). CONCLUSION Acorus tatarinowii and its active component- HMF can improve the learning and memory of rats with exercise-induced fatigue, and the mechanism is related to the up-regulation of ERK / CREB signal in hippocampus of rats with exercise-induced fatigue.
Acorus ; chemistry ; Animals ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Fatigue ; drug therapy ; Furaldehyde ; analogs & derivatives ; pharmacology ; Hippocampus ; metabolism ; MAP Kinase Signaling System ; Maze Learning ; drug effects ; Memory ; drug effects ; Physical Conditioning, Animal ; Phytochemicals ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To investigate the effects of berberine on learning and memory ability in vascular cognitive impairment rats. METHODS: Sixty-eight Wistar rats were randomly divided into control group (n=10), sham operated group (n=10) and the modeling group of vascular cognitive impairment rat (n=48), then the rats in modeling group were randomly divided into four groups (n=10): vehicle group, berberine low dose group (20 mg/kg), medium dose group (40 mg/kg) and high dose group (60 mg/kg). Bilateral common carotid arteries were occluded in rats to establish vascular cognitive impairment (VCI) model. Different doses of berberine were intraperitoneally injected into the treatment group and normal saline was intraperitoneally injected into the other groups once a day for a total of 34 days. After 28 days of administration, Morris water maze was used to test the learning and memory ability of rats. After the water maze experiment, the levels of superoxide dismutase (SOD) activity, glutathione (GSH), malondialdehyde (MDA), tumor necrosis factor alpha(TNF-α), interleukin-1 beta (IL-1β), 5-hydroxytryptamine (5-HT) and monoamine oxidase (MAO) in the forebrain cortex were detected. RESULTS: Compared to sham group, the escape latency in VCI group was significantly extended (P＜0.01) and the times of passing through the platform were decreased remarkably (P＜0.01). The levels of SOD, GSH and 5-HT in the hippocampus or anterior cortex were decreased significantly (P＜0.01), while the contents of MDA, TNF-α, IL-1β and MAO were increased remarkably (P＜0.01). Compared with VCI group, the escape latency in berberine-treated groups was shortened significantly (P＜0.01, P＜0.05) and the times of passing through the platform were increased remarkably (P＜0.01, P＜0.05), the levels of SOD, GSH and 5-HT were increased significantly (P＜0.01), while the contents of TNF-α, IL-1β and MAO were decreased remarkably (P＜0.01). CONCLUSION Berberine could significantly improve the spatial learning and memory abilities of rats with vascular cognitive impairment. The mechanism may be related to the effects of berberine on the hippocampal antioxidant stress, anti-inflammatory response and the monoamine neurotransmitter system in the forebrain cortex. Berberine 60 mg/kg dose group had better effect.
Animals ; Berberine ; pharmacology ; Cognitive Dysfunction ; drug therapy ; Hippocampus ; Inflammation ; Maze Learning ; drug effects ; Memory ; drug effects ; Oxidative Stress ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Rats, Wistar

OBJECTIVE: To study the effect of β-sheet blocking peptide H102 on the expression of AMPK-mTOR autophagy pathway-related protein in APP/PS1 double transgenic AD mice. METHODS: Thirty male APP/PS1 transgenic male AD mice of 6 months old were randomly divided into AD group and H102 intervention group, and C57BL/6J male mice of the same age were used as control group (n=15). The mice in the HF group were administered with 5 μl (5.8 mg/kg) of H102 polypeptide solution through the nasal cavity at the same time period, and the mice in the control group and the AD group were given the same amount of blank adjuvant solution daily. The memory recognition ability was tested by a new object recognition experiment 30 days after continuous administration. Immunohistochemistry and Western blot were used to detect the expressions of phosphorylated AMP-activated protein kinase(P-AMPK),phosphorylated mammalian target of rapamycin (P-mTOR) and ratio of LC32to LC31(LC3II/I )in brain tissue. RESULTS: Compared with the control group, the new object recognition index (RI) of the AD group was significantly lower (P＜0.05), and the P-AMPK and LC3II/I ratios in the brain of the mice were significantly lower (P＜0.05). The expression of P-mTOR protein was increased significantly (P＜0.05). Compared with the AD group, the RI of the H102 intervention group was increased significantly (P＜0.05), and the P-AMPK and LC3II/I ratios in the brain tissue of the mice were increased significantly (P＜0.05). The expression of P-mTOR protein was decreased significantly (P＜0.05). CONCLUSION H102 can improve the recognition and memory ability of AD mice by activating the AMPK-mTOR autophagy-related pathway.
AMP-Activated Protein Kinases ; drug effects ; Alzheimer Disease ; Amyloid beta-Protein Precursor ; Animals ; Autophagy ; drug effects ; Disease Models, Animal ; Male ; Memory ; drug effects ; Mice ; Mice, Inbred C57BL ; Mice, Transgenic ; Peptides ; pharmacology ; Random Allocation ; TOR Serine-Threonine Kinases ; drug effects

Valproic acid (VPA), an agent that is used to treat epileptic seizures, can cause spatial memory impairment in adults and children. This effect is thought to be due to the ability of VPA to inhibit neurogenesis in the hippocampus, which is required for learning. We have previously used an animal model to show that VPA significantly impairs hippocampal-spatial working memory and inhibits neuronal generation in the sub-granular zone of the dentate gyrus. As there are patient reports of improvements in memory after discontinuing VPA treatment, the present study investigated the recovery of both spatial memory and hippocampal neurogenesis at two time points after withdrawal of VPA. Male Wistar rats were given intraperitoneal injections of 0.9% normal saline or VPA (300 mg/kg) twice a day for 10 d. At 1, 30, or 45 d after the drug treatment, the novel object location (NOL) test was used to examine spatial memory; hippocampal cell division was counted using Ki67 immunohistochemistry, and levels of brain-derived neurotrophic factor (BDNF) and Notch1 were measured using western immunoblotting. Spatial working memory was impaired 1 and 30 d after the final administration, but was restored to control levels by 45 d. Cell proliferation had increased to control levels at 30 and 45 d. Both markers of neurogenesis (BDNF and Notch1 levels) had returned to control levels at 45 d. These results demonstrate that memory recovery occurs over a period of six weeks after discontinuing VPA treatment and is preceded by a return of hippocampal neurogenesis to control levels.
Animals ; Brain-Derived Neurotrophic Factor/metabolism* ; Cell Proliferation ; Cognition/drug effects* ; Dentate Gyrus/drug effects* ; Enzyme Inhibitors/pharmacology* ; Hippocampus/metabolism* ; Immunohistochemistry ; Male ; Memory Disorders/therapy* ; Memory, Short-Term/drug effects* ; Neurogenesis/drug effects* ; Neurons/metabolism* ; Rats ; Rats, Wistar ; Receptor, Notch1/metabolism* ; Spatial Memory/drug effects* ; Valproic Acid/pharmacology*

OBJECTIVETo observe the effect of puerarin on methyl-CpG binding protein 2 (MeCP2) phosphorylation (pMeCP2) in the hippocampus of a rat model of vascular dementia (VD).

METHODSThirty-six healthy Sprague-Dawley rats were randomly assigned to the sham-operated group, dementia group and puerarintreated group using a random number table (n=12 per group). The modifified permanent bilateral common carotid artery occlusion method was used to establish the VD model. The sham-operated and dementia groups were given 2 mL/d of saline, while the puerarin-treated group was given 100 mg/(kg•d) of puerarin for 17 days. The learning and memory abilities were evaluated by the Morris water maze test. Hematoxylin-eosin staining, immunohistochemical (IHC) staining and Western blot analysis were carried out to observe changes in neuron morphology and in level of pMeCP2 in the hippocampus, respectively.

RESULTSThe morphologies of rat hippocampal neurons in the puerarintreated group were markedly improved compared with the dementia group. The escape latency of the dementia group was significantly longer than the sham-operated group (P<0.05), while the puerarin-treated group was obviously shorter than the dementia group (P<0.05). Cross-platform times of the dementia group were signifificantly decreased compared with the sham-operated group (P<0.05), while the puerarin-treated group was obviously increased compared with the dementia group (P<0.05). IHC staining showed no significant difference in the number of MeCP2 positive cells among 3 groups (P>0.05). The number of pMeCP2 positive cells in the CA1 region of hippocampus in the dementia group was signifificantly increased compared with the sham-operated group, and the puerarin-treated group was signifificantly increased compared with the dementia group (both P<0.05). Western blot analysis showed no signifificant difference of MeCP2 expression among 3 groups (P>0.05). The expression of pMeCP2 in the dementia group was signifificantly increased compared with the sham-operated group, while it in the puerarin-treated group was signifificantly increased compared with the dementia group (P<0.05).

CONCLUSIONPuerarin could play a role in the protection of nerve cells through up-regulating pMeCP2 in the hippocampus, improving neuron morphologies, and enhancing learning and memory ablities in a rat model of VD.

Animals ; Dementia, Vascular ; drug therapy ; genetics ; physiopathology ; Hippocampus ; pathology ; Isoflavones ; chemistry ; pharmacology ; therapeutic use ; Memory ; drug effects ; Methyl-CpG-Binding Protein 2 ; metabolism ; Phosphorylation ; drug effects ; Rats, Sprague-Dawley ; Up-Regulation ; drug effects

OBJECTIVETo research Angelica tenuissima Nakai (ATN) for use in novel Alzheimer's disease (AD) therapeutics.

METHODSThe effect of a 30% ethanol extract of ATN (KH032) on AD-like cognitive impairment and neuropathological and neuroinflammatory changes induced by bilateral intracerebroventricular injections of β-amyloid (Aβ) peptide (Aβ) was investigated. Male C57Bl/6 mice were randomly divided into 4 groups, 10 in each group. KH032-treated groups were administrated with a low or high dose of KH032 (50 and 200 mg/kg, respectively), intragastrically for 16 days; distilled water was applied in the sham and negative groups. Open fifield test, Y maze and Morris water maze test were used for behavior test and cognitive ability. In addition, the neuroprotective effects of KH032 in Aβ-infused mice on the histopathological markers [neuronspecific nuclear protein (NeuN), Aβ] of neurodegeneration were examined. The levels of glial fibrillary acidic protein (GFAP), NeuN, phosphorylation extracellular signal-regulated kinase (ERK)/ERK, brain-derived neurotrophic factor (BDNF), phosphorylation cAMP response element-binding (CREB)/CREB protein expression were measured by Western blot.

RESULTSKH032 treatment ameliorated cognitive impairments, reduced the overexpression of Aβ, and inhibited neuronal loss and neuroinflammatory response in the Aβ-infused mice. Moreover, KH032 treatment enhanced BDNF expression levels in the hippocampus. Finally, KH032 treatment increased phosphorylation of ERK1/2 and CREB, vital for ERK-CREB signaling.

CONCLUSIONSKH032 attenuated cognitive defificits in the Aβ-infused mice by increasing BDNF expression and ERK1/2 and CREB phosphorylation and inhibiting neuronal loss and neuroinflflammatory response, suggesting that KH032 has therapeutic potential in neurodegenerative disorders such as AD.

Alzheimer Disease ; drug therapy ; pathology ; physiopathology ; Amyloid beta-Peptides ; Angelica ; chemistry ; Animals ; Brain ; pathology ; Brain-Derived Neurotrophic Factor ; metabolism ; Cognitive Dysfunction ; complications ; drug therapy ; physiopathology ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Disease Models, Animal ; Male ; Maze Learning ; drug effects ; Memory, Short-Term ; drug effects ; Mice, Inbred C57BL ; Neurogenesis ; drug effects ; Neuroglia ; drug effects ; metabolism ; pathology ; Neurons ; drug effects ; metabolism ; pathology ; Neuroprotective Agents ; pharmacology ; therapeutic use ; Phosphorylation ; drug effects ; Phytotherapy ; Plant Extracts ; pharmacology ; therapeutic use ; Plaque, Amyloid ; drug therapy ; pathology ; physiopathology ; Signal Transduction ; drug effects

OBJECTIVE: To investigate the effects of propofol combined with hypoxia on cognitive function of immature rats and the possible role of p38 pathway and tau protein in mediating such effects. METHODS: Ninety 7-day-old (P7) SD rats were randomized for daily intraperitoneal injection of propofol (50 mg/kg) or lipid emulsion (5.0 mL/kg) for 7 consecutive days. After each injection, the rats were placed in a warm box (38 ℃) with an oxygen concentration of 18% (hypoxia), 21% (normal air), or 50% (oxygen) until full recovery of the righting reflex. Another 90 P7 rats were similarly grouped and received intraperitoneal injections of p-p38 blocker (15 mg/kg) 30 min before the same treaments. The phosphorylated tau protein, total tau protein and p-p38 content in the hippocampus were detected using Western blotting. The spatial learning and memory abilities of the rats were evaluated with Morris water maze test. RESULTS: Compared with lipid emulsion, propofol injection resulted in significantly increased levels of p-p38, phosphorylated tau and total tau proteins in rats with subsequent hypoxic or normal air treatment ( < 0.05), but propofol with oxygen and injections of the blocker before propofol did not cause significant changes in the proteins. Without subsequent oxygenation, the rats receiving injections of propofol, with and without prior blocker injection, all showed significantly prolonged latency time and reduced platform-crossing times and third quadrant residence time compared with the corresponding lipid emulsion groups ( < 0.05). With oxygen treatment, the rats in propofoland blocker-treated groups showed no significant difference in the performance in Morris water maze test from the corresponding lipid emulsion group. The results of Morris water maze test differed significantly between blocker-propofol group and propofol groups irrespective of exposures to different oxygen levels ( < 0.05), but not between the lipid emulsion and blocker group pairs with exposures to different oxygen levels. CONCLUSIONS Propofol combined with hypoxia can affect the expression of tau protein through p38 pathway to impair the cognitive function of immature rats, in which oxygen plays a protective role.
Animals ; Cognitive Dysfunction ; etiology ; metabolism ; Hippocampus ; chemistry ; Hypnotics and Sedatives ; pharmacology ; Hypoxia, Brain ; complications ; metabolism ; MAP Kinase Signaling System ; Maze Learning ; drug effects ; physiology ; Memory ; drug effects ; physiology ; Propofol ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; tau Proteins ; analysis