OBJECTIVE: To observe the expressions of sphingosine kinase 1 (SphK1) and sphingosine-1-phosphate receptor 2 (S1PR2) in hippocampus of epileptic rats and to investigate the pathogenesis of SphK1 and S1PR2 in epilepsy. METHODS: One hundred and eight male Sprague-Dawley (SD) rats were randomly divided into control group (n=48) and pilocarpine (PILO) group (n=60). A robust convulsive status epilepticus (SE) was induced in PILO group rats by the application of pilocarpine. Control group rats were injected with respective of physiological saline. Pilocarpine group was randomly divided into 6 subgroups (n=8): acute group (E6 h, E1 d, E3 d), latent group (E7 d) and chronic group (E30 d, E56 d). Each subgroup has 8 control rats and 8 epileptic rats. Hippocampal tissue and brain slices were obtained from control rats and rats subjected to the Li-PILO model of epilepsy at 6 h, 1 d, 3 d,7 d,30 d and 56 d after status epilepticus (SE). Western blot technique was used to determine the expressions of SphK1 and S1PR2 in hippocampus at different point of time after pilocarpine treatment. Immunofluorescence was applied to detect the activation and proliferation of hippocampal astrocytes and the localization of SphK1 and S1PR2 in rat hippocampal astrocytes. RESULTS: Compared with control group, the levels of SphK1 in acute phase (E3 d), latent phase (E7 d) and chronic phase (E30 d, E56 d) were significantly increased while the expressions of S1PR2 were decreased in acute phase (E3 d), latent phase (E7 d) and chronic phase (E30 d, E56 d)(P＜0.05 or P＜0.01). Immunofluorescence results showed astrocyte activation and proliferation in hippocampus of epileptic (E7 d) rats (P＜0.05). Confocal microscopy confirmed the preferential expressions of SphK1 and S1PR2 in epileptic rat(E7 d)hippocampal astrocytes. CONCLUSION The results indicate that SphK1 and S1PR2 may play an important role in the pathogenesis of epilepsy by regulating the activation and proliferation of hippocampal astrocytes and altering neuronal excitability.
Animals ; Astrocytes ; enzymology ; Epilepsy ; enzymology ; physiopathology ; Hippocampus ; cytology ; enzymology ; Male ; Phosphotransferases (Alcohol Group Acceptor) ; metabolism ; Pilocarpine ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, Lysosphingolipid ; metabolism

PURPOSE: To investigate the effects of hyperbaric oxygen (HBO) pretreatment on cognitive decline and neuronal damage in an Alzheimer’s disease (AD) rat model. MATERIALS AND METHODS: Rats were divided into three groups: normal saline (NS), AD, and HBO+AD. In the AD group, amyloid β peptide (Aβ)₁₋₄₀ was injected into the hippocampal CA1 region of the brain. NS rats received NS injection. In the HBO+AD group, rats received 5 days of daily HBO therapy following Aβ₁₋₄₀ injection. Learning and memory capabilities were examined using the Morris water maze task. Neuronal damage and astrocyte activation were evaluated by hematoxylin-eosin staining and immunohistochemistry, respectively. Dendritic spine density was determined by Golgi-Cox staining. Tumor necrosis factor-α, interleukin-1β, and interleukin-10 production was assessed by enzyme-linked immunosorbent assay. Neuron apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling. Protein expression was examined by western blotting. RESULTS: Learning and memory dysfunction was ameliorated in the HBO+AD group, as shown by significantly lower swimming distances and escape latency, compared to the AD group. Lower rates of neuronal damage, astrocyte activation, dendritic spine loss, and hippocampal neuron apoptosis were seen in the HBO+AD than in the AD group. A lower rate of hippocampal p38 mitogen-activated protein kinase (MAPK) phosphorylation was observed in the HBO+AD than in the AD group. CONCLUSION: HBO pretreatment improves cognition and reduces hippocampal damage via p38 MAPK in AD rats.
Alzheimer Disease/*therapy ; Amyloid beta-Peptides/*administration & dosage ; Animals ; Apoptosis ; *Cognition/drug effects ; Disease Models, Animal ; Enzyme-Linked Immunosorbent Assay ; Hippocampus/*enzymology ; *Hyperbaric Oxygenation ; In Situ Nick-End Labeling ; Interleukin-10/biosynthesis ; Interleukin-1beta/biosynthesis ; Learning/drug effects ; Male ; Memory/drug effects ; Neurons ; Peptide Fragments/*administration & dosage ; Rats ; Rats, Sprague-Dawley ; Sodium Chloride/administration & dosage ; Tumor Necrosis Factor-alpha/biosynthesis ; p38 Mitogen-Activated Protein Kinases/*metabolism

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

In the present study, we investigated the effects of treadmill exercise on lipid peroxidation and Cu,Zn-superoxide dismutase (SOD1) levels in the hippocampus of Zucker diabetic fatty (ZDF) rats and lean control rats (ZLC) during the onset of diabetes. At 7 weeks of age, ZLC and ZDF rats were either placed on a stationary treadmill or made to run for 1 h/day for 5 consecutive days at 16~22 m/min for 5 weeks. At 12 weeks of age, the ZDF rats had significantly higher blood glucose levels and body weight than the ZLC rats. In addition, malondialdehyde (MDA) levels in the hippocampus of the ZDF rats were significantly higher than those of the ZLC rats whereas SOD1 levels in the hippocampus of the ZDF rats were moderately decreased. Notably, treadmill exercise prevented the increase of blood glucose levels in ZDF rats. In addition, treadmill exercise significantly ameliorated changes in MDA and SOD1 levels in the hippocampus although SOD activity was not altered. These findings suggest that diabetes increases lipid peroxidation and decreases SOD1 levels, and treadmill exercise can mitigate diabetes-induced oxidative damage in the hippocampus.
Animals ; Diabetes Mellitus/enzymology/*metabolism ; Female ; Gene Expression Regulation, Enzymologic ; Genotype ; Hippocampus/*enzymology/metabolism ; Lipid Peroxidation/*physiology ; Male ; Malondialdehyde/metabolism ; Physical Conditioning, Animal/*physiology ; Rats ; Rats, Zucker ; Superoxide Dismutase/genetics/*metabolism

OBJECTIVETo observe the effects of polydatin on learning and memory and cyclin-dependent kinase 5 (Cdk5) kinase activity in the hippocampus of rats with chronic alcoholism.

METHODSForty rats were randomly divided into 4 groups: control group, chronic alcoholism group, low and high polydatin group. The rat chronic alcoholism model was established by ethanol 3.0 g/(kg · d) (intragastric administration). The abstinence scoring was used to evaluate the rats withdrawal symptoms; cognitive function was measured by Morris water maze experiment; Cdk5 protein expression in the hippocampus was detected by immunofluorescence; Cdk5 kinase activity in the hippocampus was detected by liquid scintillation counting method.

RESULTSThe abstinence score, escape latency, Cdk5 kinase activity in chronic alcoholism group rats were significantly higher than those of control group (P < 0.05). The abstinence score, escape latency in high polydatin group rats were significantly lower than those of chronic alcoholism group (P < 0.05); Cdk5 kinase activity in high and low polydatin group rats was significantly lower than that of chronic alcoholism group( P < 0.05); immunofluorescence showed that the Cdk5 positive cells of chronic alcoholism group were significantly increased compared with control group (P < 0.05), and the Cdk5 positive cells of polydatin groups were significantly decreased compared with chronic alcoholism group ( P < 0.05).

CONCLUSIONPolydatin-reduced the chronic alcoholism damage may interrelate with regulation of Cdk5 kinase activity.

Alcoholism ; physiopathology ; Animals ; Cyclin-Dependent Kinase 5 ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Glucosides ; pharmacology ; Hippocampus ; drug effects ; enzymology ; Learning ; drug effects ; Memory ; drug effects ; Rats ; Stilbenes ; pharmacology

OBJECTIVE: To investigate the effect of benzo(α)pyrene on the ATPase activity and content of Ca²⁺ in the hippocampus of neonatal SD rats. METHODS: Sixty male and 60 female 4-days-old neonatal SD rats were randomly divided into 5 groups (n=24): a blank control group, a vehicle control group (peanut oil), 3 benzo(α)pyrene groups (0.02, 0.2 and 2 mg/kg, respectively). SD rats were given benzo(α)pyrene (dissolved in peanut oil) by gavage daily from postnatal day 4 (PND4) to PND20. The nerve reflex, the condition of neuro-muscle development and motion function were examined in the period of treatment. The colorimetric technique was used to detect the activity of Ca²⁺-ATPase and Ca²⁺-Mg²⁺-ATPase in hippocampus after the treatment. The concentration of Ca²⁺ of synapse in the hippocampus of rats was detected by fluorescent labeling. RESULTS: The results from the behavior tests showed that duration of surface reflex latency in rats with medium dose of benzo(α)pyrene was longer compared with that in the control group in PND12. The duration of surface reflex latency in rats with high dose of benzo(α) pyrene is longer in PND 14 and PND 16 compared with that in the control group (P<0.05). Compared with the rats in the control group, the activities of Ca²⁺-Mg²⁺-ATPase and Ca²⁺-ATPase in hippocampus in rats with high dose benzo(α) pyrene were significantly decreased, and the degree in the decrease of Ca²⁺-ATPase activity was dose-dependent (P<0.05). The contents of Ca²⁺ in the hippocampus in rats with medium or high dose of benzo(α) pyrene were significantly increased compared with that in the control group (P<0.05), which showed a dose-dependent manner (P<0.05). CONCLUSION Benzo(α)pyrene exposure led to the decrease in ATPase activity as well as Ca²⁺ overload of the synapse in the hippocampal tissue, which in turn results in the nerve damage of newborn SD rats.
Animals ; Benzo(a)pyrene ; toxicity ; Ca(2+) Mg(2+)-ATPase ; metabolism ; Calcium ; metabolism ; Calcium-Transporting ATPases ; metabolism ; Female ; Hippocampus ; enzymology ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the effect of Tongluo Xingnao effervescent tablets on learning and memory capacity and expression of Na(+)-K(+)-ATPase in hippocampus of rats with chronic cerebral ischemia-induced learning and memory dysfunction model.

METHODThe 2-VO method was used to establish sd rat model learning and memory dysfunction induced by chronic cerebral ischemia. The 50 rats in the successfully established model were randomly divided into the model control group, the Dihydroergotoxine Mesylate tablets group (0.7 mg x kg(-1), Tongluo Xingnao effervescent tablets high dose (7.56 g x kg(-1)), middle dose (3.78 g x kg(-1)) and low dose (1.59 g x kg(-1)) groups and the sham operation group (n = 10) as the control group. The groups were orally given 10 ml x kg(-1) x d(-1) drugs for consecutively 90 days. On the 86th day, Morris water maze was adopted for them. On the 90th day, a leaning and memory capacity test was held. The brain tissues were fixed with 10% formaldehyde and observed for pathomorphism after routine slide preparation and staining. The expression of hippocampal Na(+)-K(+)-ATPase was detected with immunohistochemistry and image quantitative analysis.

RESULTCompared with the model group, all of Tongluo Xingnao effervescent tablets groups showed significant decrease in the escape latency at the 5th day in the Morris water maze, and notable increase in the frequency of the first quadrant dwell, the frequency passing the escape platform and the frequency entering effective area (p < 0.05). According to the pathomorphological detection, the control group showed a significantly higher pathological score than the sham operation group (p < 0.01), the middle dose group showed a significantly lower pathological score than the model group (p < 0.05). According to the immunohistochemistical detection, the model control group showed a remarkably lower mean OD value of Na(+)-K(+)-ATPase than the sham operation group (p < 0.05), high and middle dose groups showed a significantly higher mean od value than the model control group (p < 0.01).

CONCLUSIONTongluo Xingnao effervescent tablets can improve the learning and memory capacity, reduce pathological changes of hippocampal tissues of rats with chronic cerebral ischemia-induced learning and memory dysfunction model, and promote the expression of Na(+)-K(+)-ATPase in hippocampus.

Animals ; Brain Ischemia ; drug therapy ; enzymology ; genetics ; psychology ; Chronic Disease ; drug therapy ; psychology ; Drugs, Chinese Herbal ; administration & dosage ; Female ; Hippocampus ; drug effects ; enzymology ; Humans ; Learning ; drug effects ; Male ; Memory ; drug effects ; Rats ; Rats, Sprague-Dawley ; Sodium-Potassium-Exchanging ATPase ; genetics ; metabolism ; Tablets ; administration & dosage

OBJECTIVETo explore the expression of p-p38 MAPK protein and the number of astrocytes expressing p-p38 MAPK in CA1 hippocampus in rats during the induction of brain ischemic tolerance induced by intermittent hypobaric hypoxia (IH) preconditioning.

METHODSThirty healthy adult male Wistar rats were randomly divided into 6 groups (n = 5 in each group): sham 0 min group, IH + sham 0 min group, sham 7 d group, IH + sham 7 d group, Ischemia (Is) 7 d group, and IH + Is 7 d group. Neuropathological evaluation was performed by thionine staining in CA1 hippocampus in rats. The expression of p-p38 MAPK in CA1 hippocampus was observed by immunohistochemical staining. And the number of astrocytes expressing p-p38 MAPK was observed by immunofluorescent double labeling.

RESULTSThe results showed that IH preconditioning induced brain ischemic tolerance successfully. At the same time, IH preconditioning obviously up-regulated the expression of p-p38 MAPK protein in CA1 hippocampus, and also increased the number of astrocytes expressing p-p38 MAPK.

CONCLUSIONIt might be concluded that IH preconditioning induced brain ischemic tolerance by up-regulating the expression of p-p38 MAPK protein in pyramidal neurones and astrocytes.

Animals ; Astrocytes ; enzymology ; pathology ; Brain Ischemia ; enzymology ; pathology ; Disease Models, Animal ; Hippocampus ; enzymology ; Hypoxia ; Ischemic Preconditioning ; methods ; Male ; Phosphorylation ; Pressure ; Rats ; Rats, Wistar ; p38 Mitogen-Activated Protein Kinases ; metabolism

BACKGROUNDBrain dysfunction is a frequent complication of sepsis, usually defined as sepsis-associated encephalopathy (SAE). Although the Notch signaling pathway has been proven to be involved in both ischemia and neuronal proliferation, its role in SAE is still unknown. Here, the effect of the Notch signaling pathway involved γ-secretase inhibitor DAPT on SAE in septic rats was investigated in a cecal ligation and puncture (CLP) model.

METHODSFifty-nine Sprague-Dawley rats were randomly divided into four groups, with the septic group receiving the CLP operation. Twenty-four hours after CLP or sham treatment, rats were sacrificed and their hippocampus was harvested for Western blot analysis. TNF-α expression was determined using an enzyme-linked immunosorbent assay (ELISA) kit. Neuronal apoptosis was assessed by TUNEL staining, and neuronal cell death was detected by H&E staining. Finally, a novel object recognition experiment was used to evaluate memory impairment.

RESULTSOur data showed that sepsis can increase the expression of hippocampal Notch receptor intracellular domain (NICD) and poly (adenosine diphosphate [ADP]-ribose) polymerase-1 (PARP-1), as well as the inflammatory response, neuronal apoptosis, neuronal death, and memory dysfunction in rats. The γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-phenylglycine t-butyl ester (DAPT) can significantly decrease the level of NICD and PARP-1, reduce hippocampal neuronal apoptosis and death, attenuate TNF-α release and rescue cognitive impairment caused by CLP.

CONCLUSIONThe neuroprotective effect of DAPT on neuronal death and memory impairment in septic rats, which could be a new therapeutic approach for treating SAE in the future.

Amyloid Precursor Protein Secretases ; antagonists & inhibitors ; Animals ; Apoptosis ; drug effects ; Dipeptides ; therapeutic use ; Hippocampus ; drug effects ; metabolism ; Male ; Neurons ; cytology ; drug effects ; Neuroprotective Agents ; Poly (ADP-Ribose) Polymerase-1 ; Poly(ADP-ribose) Polymerases ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Notch ; metabolism ; Sepsis ; complications ; Sepsis-Associated Encephalopathy ; drug therapy ; enzymology ; Signal Transduction ; drug effects

In order to explore the possible mechanism of EA (Electroacupuncture) in improving cognitive impairment, the present study was to research the effect of EA on the behavior and expression of the hippocampal neuronal nitric oxide synthase (nNOS) protein of the ovariectomized rats. Forty female SD rats were randomly and equally divided into four groups: sham group (ovarian fat around removal), model group (ovariectomy), sham EA group (sham EA stimulation after ovariectomy) and EA group (EA stimulation after ovariectomy). Two weeks after the ovariectomy, EA and sham EA were applied continuously for 3 months. In the experiment, Morris water maze was used to test the ability of spatial learning and memory, while enzyme-linked immuno sorbent assay (ELISA) and Western blot (WB) were used to detect the concentration of serum estradiol (E2) and relative expression of nNOS protein. The results showed that the escape latency of the EA and sham EA groups was shortened and the number of platform-crossing was significantly increased. The concentration of serum E2 and the expression of nNOS protein in both EA group and sham EA group were significantly elevated compared to those in the model group, while increment in the EA group was more significant (P<0.01). It could be concluded that from above experimental results, EA could be capable of improving learning and memory in ovariectomized rats by promoting the expression of nNOS protein through increasing the concentration of estrogen.
Animals ; Behavior, Animal ; Cognition Disorders ; prevention & control ; Electroacupuncture ; Estradiol ; blood ; Female ; Hippocampus ; enzymology ; Learning ; Memory ; Neurons ; enzymology ; Nitric Oxide Synthase Type I ; metabolism ; Ovariectomy ; adverse effects ; Rats ; Rats, Sprague-Dawley