BACKGROUNDIncreasing age was shown to decrease the requirements for propfol. However, the mechanisms of ageing-induced potentiation of anesthetic actions have not been clearly explored. The aim of this study is to compare the effects of propofol on the field excitatory postsynaptic potentials (fEPSPs) in hippocampal slices of young and aging mice.

METHODSBrain slices were prepared from C57BL6 male young (2 months) and aging (>12 months) mice. The dendritic field excitatory postsynaptic potential was recorded from the CA1 stratum radiatum using patch clamp electrophysiological methods. A bipolar concentric stimulating electrode was placed along the Schaffer collateral for othodromic stimulation. The effects of clinically-relevant concentrations of propofol were studied in the young and ageing mouse tissues.

RESULTSPropofol application increased the orthodromically evoked fEPSP produced in slices taken from young and older animals. A striking feature in the I/O relationship was the decreased enhancement of the fEPSPs by propofol in slices from older mice. A clinically relevant concentration of propofol, 10 µmol/L, showed more significant enhancement in amplitude and area under the curve (AUC) of fEPSP in young compared to tissues from older mice (amplitude: young (24.9 ± 3.4)%, old (4.6 ± 1.6)%; AUC young (30.6 ± 5.4)%, old (2.1 ± 1.7)%). There was no statistically significant difference between the paired-pulse facilitation (PPF) ratios calculated for the responses obtained in tissues from young mice. In slices from older mice, in the presence of 10 µmol/L propofol, PPF was decreased and returned to baseline after washout (baseline 1.21 ± 0.01, propofol: 1.16 ± 0.01). Bicuculline (15 µmol/L) blocked the enhancement of propofol on fEPSP in tissues from young and old mice.

CONCLUSIONThe fEPSP of slices from aging mice demonstrates diminished sensitivity to the enhancing actions of propofol.

Animals ; CA1 Region, Hippocampal ; drug effects ; metabolism ; Excitatory Postsynaptic Potentials ; drug effects ; Male ; Mice ; Mice, Inbred C57BL ; Propofol ; pharmacology

OBJECTIVETo study the roles of protein synthesis inhibitors in long-term potentiation(LTP) and depotentiation(DP) in hippocampal CA1 region of adult rats.

METHODSStandard extracellular recording technique was used to record field EPSP(fEPSP) evoked by Schaffer collateral stimulation from the CA1 subfield of adult rat hippocampal slices. Paired-pulse low-frequency stimulation(PP-LFS) or high-intensity paired-pulse low-frequency stimulation(HI-PP-LFS) was delivered to induce depotentiation 2 h after LTP induction induced by six theta-burst stimulations. Protein synthesis inhibitors were applied before and after LTP induction to study their roles in LTP and DP in hippocampal CA1 region of adult rats.

RESULTSWhen HI-PP-LFS was applied at 2 h after LTP induction, the depotentiation was induced. The mean fEPSP slopes reduced from 346.2%±26.3% to 207.1%±21.6%. This depotentiation was named as partial LTP depotentiation and maintained at least for 30 min. The percentage of depotentiation was 59.81%. Application of protein synthesis inhibitors, anisomycin and cycloheximide prior to tetanus resulted in smaller LTP compared to control group, and almost complete depotentiation was induced by HI-PP-LFS. With application of protein synthesis inhibitors anisomycin and cycloheximide 90 min after LTP induction, HI-PP-LFS still induced partial LTP depotentiation. However, there was no significant difference in the percentage of depotentiation between this group and control group.

CONCLUSIONHI-PP-LFS partially reverses late phase LTP. When protein synthesis inhibitors are applied prior to tetanus, LTP amplitude is markedly reduced, and HI-PP-LFS completely reverses late-phase LTP. Application of protein synthesis inhibitors after LTP induction does not significantly affect either the amplitude or depotentiation of LTP.

Animals ; CA1 Region, Hippocampal ; drug effects ; In Vitro Techniques ; Long-Term Potentiation ; Long-Term Synaptic Depression ; Protein Synthesis Inhibitors ; pharmacology ; Rats

Nicotine enhances the function of learning and memory, but the underlying mechanism still remains unclear. Hippocampal long-term potentiation (LTP) is assumed to be a cellular mechanism of learning and memory. Our previous experiments showed that with the single pulses evoking 80% of the maximal population spike (PS) amplitude, nicotine (10 μmol/L) induced LTP-like response in the hippocampal CA1 region. In the present study, the nicotinic acetylcholine receptor (nAChR) subtypes and relevant neurotransmitter releases involved in LTP-like response induced by nicotine were investigated by extracellularly recording the PS in the pyramidal cell layer in the hippocampal CA1 region in vitro. LTP-like response induced by nicotine was blocked by mecamylamine (1 μmol/L) or κ-bungarotoxin (0.1 μmol/L), but not by dihydro-β-erythtroidine (DHβE, 10 μmol/L). Moreover, it was inhibited by propranolol (10 μmol/L), but not by phentolamine (10 μmol/L) or atropine (10 μmol/L). The results suggest that noradrenaline release secondary to the activation of κ-bungarotoxin-sensitive nAChRs participates in LTP-like response induced by nicotine in the hippocampal CA1 region.
Animals ; Bungarotoxins ; CA1 Region, Hippocampal ; physiology ; Long-Term Potentiation ; drug effects ; Nicotine ; pharmacology ; Norepinephrine ; secretion ; Receptors, Nicotinic ; metabolism

OBJECTIVE: To investigate function of glycine receptors (GlyRs) at the hippocampal CA1 pyramidal cells and to characterize the pharmacological properties of these receptors at early postnatal stage. METHODS: We used whole cell patch clamp recording to study the current response in the acutely prepared hippocampal slices from postnatal day 11-13 rats induced by glycine applied in the artificial cerebrospinal fluid. RESULTS: Application of glycine to the pyramidal cells elicited strychnine sensitive chloride currents. EC50 for GlyRs respond to glycine was 123. 23 μmol/L and Hill coefficient was 1.24. Picrotoxin could partly blocked the currents. CONCLUSION Strychnine sensitive glycine receptors are functionally expressed in CA1 pyramidal neurons in rat hippocampal CA1 area at early postnatal stage, and some of GlyRs are αβ heteromeric receptors.
Animals ; CA1 Region, Hippocampal ; cytology ; Glycine ; pharmacology ; Patch-Clamp Techniques ; Pyramidal Cells ; drug effects ; Rats ; Receptors, Glycine ; metabolism ; Strychnine ; pharmacology

Action Potentials ; drug effects ; Animals ; CA1 Region, Hippocampal ; cytology ; Drug Antagonism ; Male ; Neurons ; drug effects ; Pentylenetetrazole ; pharmacology ; Propofol ; pharmacology ; Rats ; Rats, Wistar ; Synaptic Transmission ; drug effects

OBJECTIVETo explore the effect of diallyl disulfide (DADS) on hippocampal synapses and learning and memory abilities in a mouse model of A1zheimer's disease (AD).

METHODSMouse models of AD established by agglutinated Aβ1-42 injection in the lateral cerebral ventricle were randomized into 4 groups and treated with DADS at the daily doses of 0, 10, 50 and 100 mg/kg by gavage for 30 consecutive days. The learning and memory abilities of the mice were assessed with Morris water maze test; the structures of the dendritic spines and synapses in CA1 region of the hippocampus were observed under transmission electron microscope with silver staining; PSD95 and SYP protein and mRNA expressions in the hippocampus were detected with Western blotting and RT-PCR.

RESULTSCompared with the AD model mice, the mice treated with 50 and 100 mg/kg DADS showed enhanced learning and memory abilities in Morris water maze test. The dendritic spines and synapses in CA1 region of the hippocampus increased obviously and hippocampal expressions of PSD95 and SYP were enhanced in mice treated with 50 and 100 mg/kg DADS.

CONCLUSIONDADS at the daily doses of 50 and 100 mg/kg can improve the learning and memory abilities and increase the number of dendritic spines and synapses in the hippocampus in mouse models of AD.

Allyl Compounds ; pharmacology ; Alzheimer Disease ; drug therapy ; Animals ; CA1 Region, Hippocampal ; drug effects ; Disease Models, Animal ; Disulfides ; pharmacology ; Learning ; Male ; Memory ; Mice ; Synapses ; drug effects

AIMTo observe the effects of lidocaine and thiopental on the neuronal injury induced by the experimental ischemia in hippocampus slice cultures obtained from postnatal 22 days SD rats.

METHODSModel of the experimental ischemia was produced by hypoxia and glucose deprivation. Propidium iodide (PI) assay was used to observe the neuronal injury in CA1 and dentate gyrus (DG).

RESULTSAfter experimental ischemia, the peak of PI index was appeared in CA1 and DG on the first day (P < 0.01), PI index in DG was less than in CA1 (P < 0.01). PI indices were still higher during seven days after the experimental ischemia than before the experimental ischemia (P < 0.01). 10 nmol/L and 100 nmol/L concentration of lidocaine could significantly decrease PI indices in CA1 and DG (P < 0.01). 250 nmol/L and 600 nmol/L concentration of thiopental also decreased the PI indices in CA1 and DG (P < 0.01). The neuronal injury peaks were postponed to the third day after the experimental ischemia by lidocaine and thiopental.

CONCLUSIONIt suggested that lidocaine and thiopental could decrease the neuronal injury in CA1 and DG induced by the experimental ischemia, and postpone the neuronal injury peaks to the third day after the experimental ischemia.

Animals ; Brain Ischemia ; pathology ; CA1 Region, Hippocampal ; drug effects ; pathology ; In Vitro Techniques ; Lidocaine ; pharmacology ; Neurons ; drug effects ; pathology ; Rats ; Thiopental ; pharmacology

The chemical constituents and action targets of Acori Tatarinowii Rhizoma and Curcumae Radix were screened by network pharmacological method,and the mechanism of the combination of Acori Tatarinowii Rhizoma and Curcumae Radix in the treatment of epilepsy was analyzed. All chemical constituents of Acori Tatarinowii Rhizoma and Curcumae Radix were retrieved by TCMSP,and their action targets were screened. Component target PPI network was constructed. Epilepsy-related genes were retrieved from PharmGkb database,and PPI networks of disease targets were drawn by Cytoscape software. Cytoscape software was used to merge the network,screen the core network,and further analyze the gene GO function and KEGG pathway enrichment,which was verified by experimental research. One hundred and five chemical constituents of Acori Tatarinowii Rhizoma and 222 chemical constituents of Curcumae Radix were retrieved. Nineteen compounds were selected as candidate compounds according to OB and DL values. Among them,4 chemical constituents of Acori Tatarinowii Rhizoma and 15 chemical constituents of Curcumae Radix were found. A total of 88 target proteins were retrieved by retrieving TCMSP data,and PPI network was constructed. Through PharmGkb database,29 epilepsy-related genes were retrieved and disease target network was established. Cytoscape software and plug-ins were used for network merging and core network screening,and 69 genes were screened out. Through GO function analysis and KEGG pathway analysis,the mechanism of anti-epilepsy is related to prolactin signaling pathway,HTLV-Ⅰ infection signaling pathway,MAPK signaling pathway and herpes simplex infection signaling pathway. Further experimental verification showed that the serum prolactin level in epileptic rats was significantly increased. The neurons in hippocampal CA1 area degenerated,necrotized and lost 24 hours after epileptic seizure,and some neuron interstitial edema occurred. The possible mechanism of compatibility of Acori Tatarinowii Rhizoma and Curcumae Radix is related to serum prolactin level,MAPK signaling pathway,HTLV-Ⅰ infection and herpes simplex infection. The analysis may be related to viral encephalitis caused by HTLV-Ⅰ virus and herpes simplex infection,which damages nerve cells and causes seizures.
Acorus ; chemistry ; Animals ; CA1 Region, Hippocampal ; drug effects ; pathology ; Curcuma ; chemistry ; Drugs, Chinese Herbal ; pharmacology ; Epilepsy ; drug therapy ; Hippocampus ; Plant Roots ; chemistry ; Rats ; Rhizome ; chemistry

This paper was aimed to investigate the effect of gastrodin( GAS) on hippocampal neurogenesis after cerebral was chemic and to explore its mechanism of action related to NO. The cerebral ischemia model of C57 BL/6 mice was established by bilateral common carotid artery occlusion. The pathological changes in hippocampal CA1 region and the cognitive function of mice were assessed by HE staining and Morris water maze test,respectively. The count of Brd U/Neu N positive cells in dentate gyrus was detected by immunofluorescence assay. The NOS activity and the NO content were determined by colorimetric and nitrate reduction methods,respectively.The level of c GMP was measured by ELISA kit,and the PKG protein expression was tested by Western blot. On postoperative day 8,the hippocampal CA1 pyramidal neurons of mice showed irregular structure,with obvious nuclear pyknosis,loose cell arrangement and obvious decrease in the number of neurons. On postoperative day 29,the spatial learning ability and memory were decreased. These results indicated cerebral ischemia in mice. Meanwhile,the Brd U/Neu N positive cells were increased significantly in ischemic mice,indicating that neurogenesis occurred in hippocampus after cerebral ischemia. Treatment with different doses of gastrodin( 50 and 100 mg·kg-1) significantly ameliorated the pathological damages in the CA1 region,improved the ability of learning and memory,and promoted hippocampal neurogenesis. At the same time,both the NOS activity and the NO concentration were decreased in model group,but the c GMP level was increased,and the PKG protein expression was up-regulated. Gastrodin administration activated the NOS activity,promoted NO production,further increased c GMP level and up-regulated PKG protein expression. These results suggested that gastrodin can promote hippocampal neurogenesis after cerebral ischemia and improve cognitive function in mice,which may be related to the activation of NO-cGMP-PKG signaling pathway.
Animals ; Benzyl Alcohols/therapeutic use* ; Brain Ischemia/drug therapy* ; CA1 Region, Hippocampal/drug effects* ; Cognition ; Glucosides/therapeutic use* ; Mice ; Mice, Inbred C57BL ; Neurogenesis ; Signal Transduction

OBJECTIVETo explore the effect of recombinant human erythropoietin (rhEPO) on expression of brain-derived neurotrophic factor (BDNF) in different brain regions of aging rats.

METHODSForty male SD rats were randomized equally into negative control group, D-galactose group, EPO treatment group, and positive control group. Rat models of subacute aging were established by continuous subcutaneous injection of 5% D-galactose. Immunohistochemical staining was used to analyze the variation of BDNF expressions in different brain regions of the aging rats with different treatments.

RESULTSSignificant brain region-specific differences in BDNF expression were found among the rats in different groups. Compared with those in the negative control group, the numbers of BDNF-positive cells in the hippocampal CA1 region, CA3 region, dentate gyrus (DG) and frontal cortex were all decreased obviously in D-galactose group (P<0.05) but increased in both EPO group and the positive control group (P<0.05) without significant differences between the latter two groups. In the rats in the same group, the number of BDNF-positive cells varied markedly in different brain regions (P<0.05), and the expression level of BDNF was the highest in the frontal cortex followed by the hippocampal CA3 region and the dentate gyrus, and was the lowest in the hippocampal CA1 region.

CONCLUSIONTreatment with rhEPO enhances the expression of BDNF in rat neural cells, suggesting that rhEPO may protect the nervous system from aging by regulating the BDNF pathway.

Aging ; Animals ; Brain-Derived Neurotrophic Factor ; metabolism ; CA1 Region, Hippocampal ; metabolism ; CA3 Region, Hippocampal ; metabolism ; Dentate Gyrus ; metabolism ; Erythropoietin ; pharmacology ; Frontal Lobe ; metabolism ; Galactose ; Humans ; Male ; Neurons ; drug effects ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins ; pharmacology