Protective Effect of Apoptosis-Inhibitory Agent, N-Tosyl-l-Phenylalanyl Chloromethyl Ketone against Ischemia-Induced Hippocampal Neuronal Damage

Delayed neuronal death in the gerbil hippocampal CA1 sector occurs 48 to 72 hours after severe forebrain ischemia. DNA fragmentation is observed in the hippocampal CA1 neurons at around that time. We show here that an inhibitor of proteolytic process of apoptosis, N-tosyl-L-phenylalanyl chloromethyl ketone (TPCK), protected hippocampal neuronal damage by inhibition of the DNA fragmentation in a dose-dependent manner and that TPCK induced an apoptosis-regulating molecule, Bcl-2 protein, in the surviving neurons. These results suggest the prevention of apoptosis-related DNA fragmentation by TPCK may be an attractive therapeutic strategy for preserving hippocampal neurons from ischemic insult.

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TXA2 agonists inhibit high-voltage-activated calcium channels in rat hippocampal CA1 neurons

AJP Cell Physiology ◽

10.1152/ajpcell.1996.271.4.c1269 ◽

1996 ◽

Vol 271 (4) ◽

pp. C1269-C1277 ◽

Cited By ~ 6

Author(s):

K. S. Hsu ◽

C. C. Huang ◽

W. M. Kan ◽

P. W. Gean

Keyword(s):

Hippocampal Neurons ◽

Cell Voltage ◽

Specific Protein ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Whole Cell ◽

Ca1 Neurons ◽

Hippocampal Ca1 Neurons ◽

Hippocampal Ca1 ◽

Alpha 7

Whole cell voltage clamp recordings were used to investigate the effects of thromboxane A2 (TXA2) agonists on the voltage-dependent Ca2+ currents in rat hippocampal CA1 neurons. TXA2 agonists [1S-[1 alpha, 2 beta(5Z), 3 alpha(1E, 3S*)4 alpha ]]-7-[3-[3-hydroxy-4-(4'-iodophenoxy)-1-butenyl]-7-oxabicyclo [2,2,1]heptan-2-yl]-5-heptenoic acid (I-BOP) and U-46619, reversibly suppressed the whole cell Ca2+ currents in a concentration-dependent manner. The effect was blocked by specific TXA2 receptor antagonist, SQ-29548. I-BOP as well as U-46619 inhibited both omega-conotoxin GVIA (CgTx)-sensitive and nimodipine sensitive Ca2+ currents but had no effect on CgTx/nimodipine insensitive Ca2+ currents. The I-BOP and U-46619 inhibition of Ca2+ currents was blocked by internal dialysis of hippocampal neurons with specific protein kinase C (PKC) inhibitors, NPC-15437 and PKC inhibitor-(19-36). Pretreatment of hippocampal neurons with either 5 micrograms/ml pertussis toxin (PTX) or 5 micrograms/ml cholera toxin (CTX) did not significantly affect the suppression of the Ca2+ currents by I-BOP and U-46619. Dialyzing with 1 mM guanosine 5'-O-(3-thiotriphosphate) or 1 mM GDP significantly attenuated the I-BOP or U-46619 action. These results demonstrate that TXA2 agonists inhibit both CgTx- and nimodipine-sensitive Ca2+ currents but not CgTx/nimodipine-insensitive currents in rat hippocampal CA1 neurons via a PTX- and CTX-insensitive G protein-coupled activation of the PKC pathway.

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Interleukin 3 Prevents Delayed Neuronal Death in the Hippocampal CA1 Field

Journal of Experimental Medicine ◽

10.1084/jem.188.4.635 ◽

1998 ◽

Vol 188 (4) ◽

pp. 635-649 ◽

Cited By ~ 49

Author(s):

Tong-Chun Wen ◽

Junya Tanaka ◽

Hui Peng ◽

Junzo Desaki ◽

Seiji Matsuda ◽

...

Keyword(s):

Neuronal Death ◽

Hippocampal Neurons ◽

Neuronal Damage ◽

Delayed Neuronal Death ◽

Α Subunit ◽

Ca1 Neurons ◽

Hippocampal Ca1 ◽

Hippocampal Ca1 Field

In the central nervous system, interleukin (IL)-3 has been shown to exert a trophic action only on septal cholinergic neurons in vitro and in vivo, but a widespread distribution of IL-3 receptor (IL-3R) in the brain does not conform to such a selective central action of the ligand. Moreover, the mechanism(s) underlying the neurotrophic action of IL-3 has not been elucidated, although an erythroleukemic cell line is known to enter apoptosis after IL-3 starvation possibly due to a rapid decrease in Bcl-2 expression. This in vivo study focused on whether IL-3 rescued noncholinergic hippocampal neurons from lethal ischemic damage by modulating the expression of Bcl-xL, a Bcl-2 family protein produced in the mature brain. 7-d IL-3 infusion into the lateral ventricle of gerbils with transient forebrain ischemia prevented significantly hippocampal CA1 neuron death and ischemia-induced learning disability. TUNEL (terminal deoxynucleotidyltransferase–mediated 2′-deoxyuridine 5′-triphosphate-biotin nick end labeling) staining revealed that IL-3 infusion caused a significant reduction in the number of CA1 neurons exhibiting DNA fragmentation 7 d after ischemia. The neuroprotective action of IL-3 appeared to be mediated by a postischemic transient upregulation of the IL-3R α subunit in the hippocampal CA1 field where IL-3Rα was barely detectable under normal conditions. In situ hybridization histochemistry and immunoblot analysis demonstrated that Bcl-xL mRNA expression, even though upregulated transiently in CA1 pyramidal neurons after ischemia, did not lead to the production of Bcl-xL protein in ischemic gerbils infused with vehicle. However, IL-3 infusion prevented the decrease in Bcl-xL protein expression in the CA1 field of ischemic gerbils. Subsequent in vitro experiments showed that IL-3 induced the expression of Bcl-xL mRNA and protein in cultured neurons with IL-3Rα and attenuated neuronal damage caused by a free radical–producing agent FeSO4. These findings suggest that IL-3 prevents delayed neuronal death in the hippocampal CA1 field through a receptor-mediated expression of Bcl-xL protein, which is known to facilitate neuron survival. Since IL-3Rα in the hippocampal CA1 region, even though upregulated in response to ischemic insult, is much less intensely expressed than that in the CA3 region tolerant to ischemia, the paucity of IL-3R interacting with the ligand may account for the vulnerability of CA1 neurons to ischemia.

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Saikosaponin a Enhances Transient Inactivating Potassium Current in Rat Hippocampal CA1 Neurons

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2013/413092 ◽

2013 ◽

Vol 2013 ◽

pp. 1-10 ◽

Cited By ~ 6

Author(s):

Wei Xie ◽

Yun Hong Yu ◽

Yong Ping Du ◽

Yun Yan Zhao ◽

Chang Zheng Li ◽

...

Keyword(s):

Hippocampal Slices ◽

Chinese Herb ◽

Dependent Manner ◽

Activation Curve ◽

Ca1 Neurons ◽

Epileptiform Discharges ◽

Hippocampal Ca1 Neurons ◽

Hippocampal Ca1 ◽

Dose Dependent ◽

Saikosaponin A

Saikosaponin a (SSa), a main constituent of the Chinese herbBupleurum chinenseDC., has been demonstrated to have antiepileptic activity. Recent studies have shown that SSa could inhibit NMDA receptor current and persistent sodium current. However, the effects of SSa on potassium (K+) currents remain unclear. In this study, we tested the effect of SSa on 4AP-induced epileptiform discharges and K+currents in CA1 neurons of rat hippocampal slices. We found that SSa significantly inhibited epileptiform discharges frequency and duration in hippocampal CA1 neurons in the 4AP seizure model in a dose-dependent manner with anIC50of 0.7 μM. SSa effectively increased the amplitude ofITotalandIA, significantly negative-shifted the activation curve, and positive-shifted steady-state curve ofIA. However, SSa induced no significant changes in the amplitude and activation curve ofIK. In addition, SSa significantly increased the amplitude of 4AP-sensitive K+current, while there was no significant change in the amplitude of TEA-sensitive K+current. Together, our data indicate that SSa inhibits epileptiform discharges induced by 4AP in a dose-dependent manner and that SSa exerts selectively enhancing effects onIA. These increases inIAmay contribute to the anticonvulsant mechanisms of SSa.

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Effects of Propentofylline on Hypoxia—Hypoglycemia-Induced Calcium Accumulation in Gerbil Hippocampal Slices

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.1992.41 ◽

1992 ◽

Vol 12 (2) ◽

pp. 301-305 ◽

Cited By ~ 12

Author(s):

Fumito Kadoya ◽

Akira Mitani ◽

Tatsuru Arai ◽

Kiyoshi Kataoka

Keyword(s):

Cerebral Ischemia ◽

Intracellular Calcium ◽

Neuronal Damage ◽

Hippocampal Slices ◽

Dependent Manner ◽

Protective Effects ◽

Calcium Accumulation ◽

Xanthine Derivative ◽

Acute Increase ◽

Dose Dependent

The xanthine derivative propentofylline (HWA 285) has been reported to show protective effects against neuronal damage induced by cerebral ischemia. In the present study, microfluorometry was used to investigate the effect of propentofylline on the hypoxia–hypoglycemia-induced intracellular calcium accumulation in gerbil hippocampal slices. When slices were superfused with hypoxic–hypoglycemic medium that did not contain propentofylline, an acute increase in calcium accumulation was detected 75–200 s (mean latency of 123 s) after the beginning of hypoxia–hypoglycemia. When slices were superfused with hypoxic–hypoglycemic mediums that contained 10 μ M, 100 μ M, and 1 m M propentofylline, the latency of the acute increase in calcium accumulation was prolonged in all subregions of the hippocampus in a dose-dependent manner: mean latencies in field CA1 were 146, 168, and 197 s after hypoxia–hypoglycemia, respectively. This retardation in calcium accumulation may be involved in the mechanisms by which propentofylline diminishes ischemic injury.

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Theta-Frequency Resonance in Hippocampal CA1 Neurons In Vitro Demonstrated by Sinusoidal Current Injection

Journal of Neurophysiology ◽

10.1152/jn.1998.79.3.1592 ◽

1998 ◽

Vol 79 (3) ◽

pp. 1592-1596 ◽

Cited By ~ 108

Author(s):

L. Stan Leung ◽

Hui-Wen Yu

Keyword(s):

Resonant Frequency ◽

Hippocampal Neurons ◽

Ca1 Neurons ◽

Frequency Resonance ◽

Hippocampal Ca1 Neurons ◽

Hippocampal Ca1 ◽

Theta Frequency ◽

Sinusoidal Current ◽

Sinusoidal Currents

Leung, L. Stan and Hui-Wen Yu. Theta-frequency resonance in hippocampal CA1 neurons in vitro demonstrated by sinusoidal current injection. J. Neurophysiol. 79: 1592–1596, 1998. Sinusoidal currents of various frequencies were injected into hippocampal CA1 neurons in vitro, and the membrane potential responses were analyzed by cross power spectral analysis. Sinusoidal currents induced a maximal (resonant) response at a theta frequency (3–10 Hz) in slightly depolarized neurons. As predicted by linear systems theory, the resonant frequency was about the same as the natural (spontaneous) oscillation frequency. However, in some cases, the resonant frequency was higher than the spontaneous oscillation frequency, or resonance was found in the absence of spontaneous oscillations. The sharpness of the resonance ( Q), measured by the peak frequency divided by the half-peak power bandwidth, increased from a mean of 0.44 at rest to 0.83 during a mean depolarization of 6.5 mV. The phase of the driven oscillations changed most rapidly near the resonant frequency, and it shifted about 90° over the half-peak bandwidth of 8.4 Hz. Similar results were found using a sinusoidal function of slowly changing frequency as the input. Sinusoidal currents of peak-to-peak intensity of >100 pA may evoke nonlinear responses characterized by second and higher harmonics. The theta-frequency resonance in hippocampal neurons in vitro suggests that the same voltage-dependent phenomenon may be important in enhancing a theta-frequency response when hippocampal neurons are driven by medial septal or other inputs in vivo.

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Positive Allosteric Modulators of AMPA Receptors Reduce Proton-Induced Receptor Desensitization in Rat Hippocampal Neurons

Journal of Neurophysiology ◽

10.1152/jn.2001.85.5.2030 ◽

2001 ◽

Vol 85 (5) ◽

pp. 2030-2038 ◽

Cited By ~ 25

Author(s):

Saobo Lei ◽

Beverley A. Orser ◽

Gregory R. L. Thatcher ◽

James N. Reynolds ◽

John F. MacDonald

Keyword(s):

Ampa Receptor ◽

Ampa Receptors ◽

Hippocampal Neurons ◽

Organic Nitrate ◽

Receptor Desensitization ◽

Open Probability ◽

Ca1 Neurons ◽

Hippocampal Ca1 ◽

Rate Of Recovery ◽

Kinetics Of

Whole-cell or outside-out patch recordings were used to investigate the effects of protons and positive modulators of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors on the desensitization of glutamate-evoked AMPA receptor currents in isolated hippocampal CA1 neurons. Protons inhibited glutamate-evoked currents (IC50 of 6.2 pH units) but also enhanced the apparent rate and extent of AMPA receptor desensitization. The proton-induced enhancement of desensitization could not be attributed to a reduction in the rate of recovery from desensitization or to a change in the kinetics of deactivation. Non-stationary variance analysis indicated that protons reduced maximum open probability without changing the conductance of AMPA channels. The positive modulators of AMPA receptor desensitization, cyclothiazide and GT-21-005 (an organic nitrate), reduced the proton sensitivity of AMPA receptor desensitization, which suggests that they interact with protons to diminish desensitization. In contrast, the effects of wheat germ agglutinin and aniracetam on AMPA receptor desensitization were independent of pH. These results demonstrate that a reduction in the proton sensitivity of receptor desensitization contributes to the mechanism of action of some positive modulators of AMPA receptors.

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Benzodiazepines Block α2-Containing Inhibitory Glycine Receptors in Embryonic Mouse Hippocampal Neurons

Journal of Neurophysiology ◽

10.1152/jn.00612.2002 ◽

2003 ◽

Vol 90 (1) ◽

pp. 89-99 ◽

Cited By ~ 25

Author(s):

Liu Lin Thio ◽

Ananth Shanmugam ◽

Keith Isenberg ◽

Kelvin Yamada

Keyword(s):

Hippocampal Neurons ◽

Clinical Effects ◽

Dependent Manner ◽

Glycine Receptors ◽

Binding Studies ◽

Chloride Currents ◽

Embryonic Mouse ◽

Voltage Dependent ◽

Polymerase Chain ◽

Dose Dependent

Inhibitory glycine receptors (GlyRs) in the mammalian cortex probably contribute to brain development and to maintaining tonic inhibition. Given their presence throughout the cortex, their modulation likely has important physiological consequences. Although benzodiazepines potentiate γ-aminobutyric acidA receptors (GABAARs), they may also modulate GlyRs because binding studies initially suggested that they act at GlyRs. Furthermore, their diminished ability to potentiate neonatal GABAARs suggests that they may exert their beneficial clinical effects at another site in the developing brain. Therefore we examined the effect of benzodiazepines on whole cell currents mediated by GlyRs in cultured embryonic mouse hippocampal neurons. First, we determined the GlyR subunit composition in this preparation. Glycine, β-alanine, and taurine activate strychnine-sensitive chloride currents in a dose-dependent manner. Maximal concentrations of the three agonists produce equal, nonadditive responses as expected of full agonists. The pharmacological properties of the GlyR currents including their pattern of modulation by picrotoxinin, picrotin, and tropisetron indicate that GlyRs consist of α2β heteromers and α2 homomers. Reverse transcriptase polymerase chain reaction (RTPCR) studies confirmed the presence of α2 and β subunits. Second, we found that micromolar concentrations of some benzodiazepines, including chlordiazepoxide and nitrazepam, inhibit GlyR currents. Nitrazepam inhibition of GlyRs is noncompetitive, is not voltage dependent, and does not reflect enhanced desensitization. Thus benzodiazepines allosterically inhibit α2-containing GlyRs in embryonic mouse hippocampal neurons via a “low”-affinity site.

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N-Acetylaspartate to Total Creatine Ratio in the Hippocampal CA1 Sector after Transient Cerebral Ischemia in Gerbils: Influence of Neuronal Elements, Reactive Gliosis, and Tissue Atrophy

Journal of Cerebral Blood Flow & Metabolism ◽

10.1097/01.wcb.0000071888.63724.56 ◽

2003 ◽

Vol 23 (6) ◽

pp. 700-708 ◽

Cited By ~ 9

Author(s):

Kuni Konaka ◽

Hirokazu Ueda ◽

Ji-Yao Li ◽

Masayasu Matsumoto ◽

Saburo Sakoda ◽

...

Keyword(s):

High Performance ◽

Neuronal Damage ◽

Immunohistochemical Analysis ◽

Reactive Astrogliosis ◽

Hippocampal Ca1 ◽

Total Creatine ◽

Temporal Profiles ◽

Hippocampal Ca1 Sector ◽

Good Linear Correlation ◽

Observation Period

The authors compared temporal profiles of Nacetylaspartate (NAA) and the NAA/total creatine ratio with neuronal and astrocytic densities and with tissue atrophy in the hippocampal CA1 sector of gerbils after 5-minute bilateral forebrain ischemia and subsequent reperfusion for up to 6 months. The CA1 sector was dissected from 20-μm lyophilized sections (n = 5) for NAA, phosphocreatine, and creatine assays using high-performance liquid chromatography. Adjacent 10-μm sections were used for immunohistochemical analysis to follow neuronal and astrocytic responses. The NAA concentration was significantly ( P<0.01) decreased after 7 days but leveled off thereafter. The NAA/total creatine (phosphocreatine + creatine) ratio was significantly decreased after 7 days and further decreased ( P<0.05) after 6 months. Extensive neuronal damage developed beyond 7 days, while reactive astrogliosis progressed throughout the observation period. There was a good linear correlation ( P<0.01) between astroglial density and the NAA/total creatine ratio beyond 7 days. The thickness of the CA1 sector was significantly reduced after 1 month and further reduced after 6 months. Although both NAA level and the NAA/total creatine ratio seemed to be indicators of neuronal damage, the latter could be influenced by reactive astrogliosis with progression of tissue atrophy.

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Effect of Plant Compound Curcumin on the Expression of a-Synuclein in Hippocampal Neurons of APPswe/PS1dE9 Double Transgenic Mice

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.781-784.643 ◽

2013 ◽

Vol 781-784 ◽

pp. 643-646

Author(s):

Xiao Lin ◽

Li Yu

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Transgenic Mice ◽

Hippocampal Neurons ◽

Neuroprotective Effect ◽

Disease Model ◽

Dependent Manner ◽

Double Transgenic Mice ◽

Ad Alzheimer’S Disease ◽

Dose Dependent

In this study, we aim to investigate the effect of curcumin on the expression of a-synuclein in the APPswe/PS1dE9 double transgenic mice. APPswe/PS1dE9 double transgenic mice were used as AD (Alzheimer's disease) model and fed with different concentrations of curcumin every day for 6 months, then immunohistochemistry method were used to detect the expression of a-synuclein in hippocampus of mice. The expression of a-syn in hippocampal neuron was decreased significantly after treated with 0.16g/kg to 1.0g/kg curcumin, the change was apparent in dose-dependent manner (P<0.05). a-synuclein pay an important role in the genesis and development of Alzheimer's disease and decreased level of a-synuclein might contribute to the neuroprotective effect of Curcumin, which may become a new target for the prevention and treatment of Alzheimer's disease.

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