Animals ; Blotting, Western ; Cell Differentiation ; drug effects ; Embryonic Stem Cells ; cytology ; enzymology ; Isoenzymes ; analysis ; Mice ; Neurons ; enzymology ; Protein Kinase C ; analysis ; Tretinoin ; pharmacology

This in vitro study evaluated the detrimental effect of acute gamma (gamma)-irradiation on rat immature hippocampal neurons. Rat immature hippocampal neurons (0.5 day in vitro) were irradiated with 0~4 Gy gamma-rays. Cytotoxicity was analyzed using a lactate dehydrogenase release assay at 24 h after gamma-irradiation. Radiation-induced cytotoxicity in immature hippocampal neurons increased in a dose-dependent manner. Pre-treatments of pro-apoptotic caspase inhibitors and anti-oxidative substances significantly blocked gamma-irradiation-induced cytotoxicity in immature hippocampal neurons. The results suggest that the caspase-dependent cytotoxicity of gamma-rays in immature hippocampal cultured neurons may be caused by oxidative stress.
Amifostine/pharmacology ; Animals ; Antioxidants/pharmacology ; Caspase 3/metabolism/radiation effects ; Catechin/analogs & derivatives/pharmacology ; Cell Survival/radiation effects ; Cells, Cultured/cytology/enzymology/*radiation effects ; Dose-Response Relationship, Radiation ; Female ; *Gamma Rays ; Hippocampus/cytology/enzymology/*radiation effects ; L-Lactate Dehydrogenase/radiation effects ; Neurons/cytology/enzymology/*radiation effects ; Poly(ADP-ribose) Polymerases/drug effects ; Pregnancy ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effects of Erzhi Pill (二至丸,EZP) on nerve cell apoptosis in senescence model rats.

METHODSThe rats model of senescence was established by peritoneal D-galactose injection combined with thymusectomy. Forty SD rats were randomized into four groups, the normal control group, the senescence model group, the EZP treated group, and the vitamins treated group, 10 in each group. The rats were made into senescence model except those in the normal group. In the same time of D-galactose injection, the rats were treated respectively with distilled water, EZP 4.32 g/kg, and vitamins E and C 0.06 g/kg daily for 6 weeks via intragastric infusion. The index of main viscera (as brain, testis, etc.), serum levels of superoxide dismutase (SOD) activity, and total anti-oxidation capacity (T-AOC) were measured after a 6-week treatment. Meanwhile, the cerebral cortex neuronal apoptosis proportion and mitochondrial membrane potential (MMP) were detected by flow cytometry.

RESULTSBoth EZP and vitamins E and C treatments showed effects on increasing testis index and serum level of T-AOC, reducing the percentage of neuronal apoptosis in the cerebral cortex, and elevating MMP in the aging rats model.

CONCLUSIONSEZP could inhibit the cerebral cortex neuron apoptosis and maintain the mitochondrial function in the senescent process of rats induced by peritoneal D-galactose injection combined with thymusectomy. It also shows antioxidation effect to some extents.

Aging ; blood ; drug effects ; Animals ; Antioxidants ; metabolism ; Apoptosis ; drug effects ; Cerebral Cortex ; cytology ; Drugs, Chinese Herbal ; pharmacology ; Male ; Matrix Metalloproteinases ; metabolism ; Neurons ; cytology ; drug effects ; enzymology ; Rats ; Rats, Sprague-Dawley ; Superoxide Dismutase ; blood

Intravenous anesthetics are known to cause amnesia, but the underlying molecular mechanisms remain elusive. To identify a possible molecular mechanism, we recently turned our attention to a key intracellular signaling pathway organized by a family of mitogen-activated protein kinases (MAPKs). As a prominent synapse-to-nucleus superhighway, MAPKs couple surface glutamate receptors to nuclear transcriptional events essential for the development and/or maintenance of different forms of synaptic plasticity (long-term potentiation and long-term depression) and memory formation. To define the role of MAPK-dependent transcription in the amnesic property of anesthetics, we conducted a series of studies to examine the effect of a prototype intravenous anesthetic propofol on the MAPK response to N-methyl-D-aspartate receptor (NMDAR) stimulation in hippocampal neurons. Our results suggest that propofol possesses the ability to inhibit NMDAR-mediated activation of a classic subclass of MAPKs, extracellular signal-regulated protein kinase 1/2 (ERK1/2). Concurrent inhibition of transcriptional activity also occurs as a result of inhibited responses of ERK1/2 to NMDA. These findings provide first evidence for an inhibitory modulation of the NMDAR-MAPK pathway by an intravenous anesthetic and introduce a new avenue to elucidate a transcription-dependent mechanism processing the amnesic effect of anesthetics.
Amnesia ; chemically induced ; enzymology ; Anesthetics, Intravenous ; pharmacology ; Animals ; Cells, Cultured ; Extracellular Signal-Regulated MAP Kinases ; drug effects ; metabolism ; Hippocampus ; cytology ; drug effects ; enzymology ; Long-Term Potentiation ; drug effects ; physiology ; Memory ; drug effects ; physiology ; Mitogen-Activated Protein Kinase 1 ; drug effects ; Mitogen-Activated Protein Kinase 3 ; drug effects ; Neurons ; drug effects ; enzymology ; Propofol ; pharmacology ; Rats ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Signal Transduction ; drug effects ; physiology ; Transcriptional Activation ; drug effects

Brain-derived neurotrophic factor (BDNF)is the richest neurophin in brain tissue and may act as an activity-dependent neuronal survival factor. In vitro, BDNF plays an important role in preventing cortical neurons from hypoxia-induced neurotoxicity. It could induce a variety of cellular responses such as cell growth, survival, differentiation, and anti-apoptosis mainly via activating mitogen-activated protein kinase (MAPK) and Ca2+/calmodulin-dependent kinase (CaMK) signaling pathways. And among these multiple signaling pathways there is growing evidence of complicated cross talk.
Animals ; Brain-Derived Neurotrophic Factor ; pharmacology ; physiology ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; Calcium-Calmodulin-Dependent Protein Kinases ; drug effects ; physiology ; Cells, Cultured ; Humans ; Mitogen-Activated Protein Kinases ; drug effects ; physiology ; Neurons ; cytology ; drug effects ; enzymology ; Signal Transduction

OBJECTIVETo investigate the protective effects of oxysophoridine (OSR) on primary cultured hippocampus neurons subjected to anoxia injury in neonatal rats and its mechanism.

METHODThe model of anoxia injury of hippocampus neurons in neonatal rats were primarily cultured in vitro by physical oxygen deficiency using glucose-free culture fluid. The survival rate of neurons, the leaking rate of lactate dehydrogenase (LDH), the intracellular contents of malondialdehyde (MDA) and nitric oxide (NO), the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and nitric oxide synthase (NOS) were measured. The intracellular free calcium concentration ([Ca2+]i) in hippocampus neurons were detected with Ca(2+)-sensitive dual wavelength fluorescence spectrophotometer.

RESULTNeuron death occurred in the anoxia injury model group with increase of LDH leaking rate, the contents of NO, MDA, intracellular [Ca2+] and the elevated activity of NOS while decreased activities of SOD and GSH-PX. The hippocampus neurons subjected to anoxia injury were alleviated in OSR (0.625, 5, 10 microg x L(-1)) group.

CONCLUSIONOSR has significant protective effects on hippocampus neurons subjected to anoxic injury. The mechanism of its protective effect may relate to its reduction of calcium overload and against oxidation injury.

Alkaloids ; administration & dosage ; Animals ; Cells, Cultured ; Drugs, Chinese Herbal ; administration & dosage ; Female ; Glutathione Peroxidase ; metabolism ; Hippocampus ; cytology ; drug effects ; enzymology ; metabolism ; Humans ; Hypoxia ; drug therapy ; enzymology ; metabolism ; prevention & control ; Malondialdehyde ; metabolism ; Neurons ; cytology ; drug effects ; enzymology ; metabolism ; Nitric Oxide Synthase ; metabolism ; Protective Agents ; administration & dosage ; Rats ; Rats, Sprague-Dawley ; Sophora ; chemistry ; Superoxide Dismutase ; metabolism

To explore the effect of different concentrations of corticosterone (CORT) on primary cultured hippocampal neurons and their Ca2+/CaMK II expression and possible mechanism, the changes of hippocampal neurons were observed in terms of morphology, activity of cells, cell death, concentrations of cytosolic free calcium, and the expression of CaMK II by using MTT assay, flow cytometry, fluorescent labeling of Fura-2/AM and Western blotting after 10(-7), 10(-6) and 10(-5) mol/L of CORT was added to culture medium, The evident effect of 10(-6) and 10(-5) mol/L of CORT on the morphology of hippocampal neuron was found. Compared with control neurons, the activity of the cells was markedly decreased and [Ca2+]i increased in the neurons treated with 10(-6) and 10(-5) mol/L of CORT, but no change was observed in the neuron treated with 10(-7) mol/L of CORT. The death was either by way of apoptosis or necrosis in the cells treated with 10(-6) and 10(-5) mol/L of CORT respectively. The correlation analysis showed that a reverse correlation existed between [Ca2+]i and the expression of CaMK II. Either apoptosis or necrosis occurs in the hippocampal neurons treated with CORT. The increased hippocampal [Ca2+]i is both the result of CORT impairing the hippocampal neurons and the cause of the apoptosis of hippocampal neurons and the decreased CaMK II expression.
Animals ; Apoptosis ; drug effects ; Calcium ; metabolism ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; Calcium-Calmodulin-Dependent Protein Kinases ; biosynthesis ; genetics ; Cells, Cultured ; Corticosterone ; pharmacology ; Hippocampus ; cytology ; enzymology ; Neurons ; cytology ; Rats ; Rats, Wistar

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

OBJECTIVETo investigate the effects of protein tyrosine kinase (PTK), protein tyrosine phosphatase (PTP) and protein kinase C (PKC) on apoptosis and observe the changes of cytosolic calcium ([Ca(2+)]i) of arsenic trioxide (As2O3) treated human leukemia cells NB4 and cortex neurons.

METHODS[Ca(2+)]i of NB4 cells and cortex neurons was probed with Fluo-3/AM, its changes were assayed with laser confocal microscopy in real-time after As2O3 treatment at different concentrations, the effects of PTK and PTP and the activation of PKC on these changes with confocal microscopy and phosphorus radioisotope assay. DNA ladders of NB4 cells and cortex neurons after exposed to As2O3 were observed.

RESULTSAs2O3 at 1 micromol/L could remarkably increase the [Ca(2+)]i of NB4 cells but had no effects on neurons. Vanadate, a kind of PTP inhibitor, could promote the increase of [Ca(2+)]i treated by 2, 5, 10 micromol/L As2O3 in a dose-dependent manner. The mean total increase rates at 240 seconds after exposed to As2O3 at different concentrations were (6.5 +/- 2.3)%, (21.7 +/- 2.1)%, (49.2 +/- 2.5)% for NB4 cells, and (6.7 +/- 2.1)%, (19.4 +/- 2.5)%, (52.3 +/- 2.7)% for cortex neurons, respectively. Genistein, a kind of PTK inhibitor, could decrease the increase of [Ca(2+)]i treated by 2, 5, 10 micromol/L As2O3 in a dose-dependent manner. The mean total inhibited rates at 240 seconds after As2O3 treatment at different concentrations were (6.7 +/- 2.9)%, (25.6 +/- 2.5)%, (52.2 +/- 3.5)% for NB4 cells, and (7.8 +/- 3.1)%, (18.1 +/- 2.8)%, (51.3 +/- 3.3)% for cortex neurons, respectively. The activation of PKC began to increase as exposed to As2O3 at 1 micromol/L for 3 h, and kept rising continuously in NB4 cells and at 24 h DNA ladders emerged. However, none of the above results was found in human cortex neurons, but when exposed to 2 micromol/L As2O3, the activation of PKC and DNA ladders did emerge in neurons.

CONCLUSIONSThe phosphorylation and dephosphorylation of PTK and PTP participated in nonspecific apoptosis signal transduction pathway related to As2O3, and accompanied with PKC activation. The [Ca(2+)]i elevation was closely related to increased PKC activation. There existed difference in dose tolerances to As2O3 between NB4 cell and cortex neurons.

Adult ; Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Calcium ; metabolism ; Cell Line, Tumor ; Cells, Cultured ; Cerebral Cortex ; cytology ; Cytoplasm ; metabolism ; Dose-Response Relationship, Drug ; Humans ; Leukemia, Promyelocytic, Acute ; enzymology ; metabolism ; pathology ; Male ; Neurons ; cytology ; drug effects ; metabolism ; Oxides ; pharmacology ; Protein Kinase C ; metabolism ; Protein Tyrosine Phosphatases ; metabolism ; Protein-Tyrosine Kinases ; metabolism

Endothelins (ETs), which were originally found to be potent vasoactive transmitters, were known to be implicated in nervous system, but the mode of mechanism remains unclear. ETs (ET-1, ET-2, and ET-3) were added to HN33 (mouse hippocampal neuron chi neuroblastoma) cells. Among the three types of ET, only ET-1 increased the intracellular calcium levels in a PLC dependent manner with the induction of ERK 1/2 activation. As the result of ET-1 exposure, the survival rate of HN33 cells and the PKCalpha translocation into the plasma membrane were increased. We suggest that ET-1 participated in the neuroprotective effect involving the calcium-PKCalpha-ERK1/2 pathway.
Animals ; Apoptosis/*drug effects ; Calcium/*metabolism ; Cell Line ; Cell Survival/drug effects ; Cytosol/drug effects/metabolism ; Endothelin-1/*pharmacology ; Endothelin-2/pharmacology ; Endothelin-3/pharmacology ; Estrenes/pharmacology ; Extracellular Signal-Regulated MAP Kinases/*metabolism ; Immunoblotting ; Mice ; Mitogen-Activated Protein Kinase 1/metabolism ; Mitogen-Activated Protein Kinase 3/metabolism ; Neurons/*cytology/drug effects/*enzymology ; Neuroprotective Agents/pharmacology ; Phosphoproteins/metabolism ; Protein Kinase C-alpha/*metabolism ; Protein Transport/drug effects ; Pyrrolidinones/pharmacology ; Serum