p-Nitrophenylphosphatase Activity Catalyzed by Plasma Membrane (Ca2++Mg2+)ATPase: Correlation with Structural Changes Modulated by Glycerol and Ca2+

2001 ◽  
Vol 21 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Gutemberg G. Alves ◽  
Luis Maurício T. R. Lima ◽  
Maely P. Fávero-Retto ◽  
Adriana P. Lemos ◽  
Carlos E. Peres-Sampaio ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Synergistic Effect ◽  
Phosphatase Activity ◽  
Structural Changes ◽  
Center Of Mass ◽  
Binding Domain ◽  
Dependent Manner ◽  
Dose Dependent ◽  
Substrate Binding Domain

The plasma membrane (Ca2++Mg2+)ATPase hydrolyzes pseudo-substrates such as p-nitrophenylphosphate. Except when calmodulin is present, Ca2+ ions inhibit the p-nitrophenylphosphatase activity. In this report it is shown that, in the presence of glycerol, Ca2+ strongly stimulates phosphatase activity in a dose-dependent manner. The glycerol- and Ca2+-induced increase in activity is correlated with modifications in the spectral center of mass (average emission wavenumber) of the intrinsic fluorescence of the enzyme. It is concluded that the synergistic effect of glycerol and Ca2+ is related to opposite long-term hydration effects on the substrate binding domain and the Ca2+ binding domain.

A dual approach to self-stimulation and locomotor trace affected by chronic methamphetamine treatment for an animal model of schizophrenia

1993 ◽  
Vol 71 (5-6) ◽  
pp. 321-325 ◽  
Author(s):  
Morikuni Takigawa ◽  
Hiroshi Maeda ◽  
Kenichi Ueyama ◽  
Hidefumi Tominaga ◽  
Kei Matsumoto
Keyword(s):  
Animal Model ◽  
Negative Symptoms ◽  
Disease Model ◽  
Stereotyped Behavior ◽  
Dependent Manner ◽  
Dual Approach ◽  
Reverse Tolerance ◽  
Self Stimulation ◽  
Dose Dependent

The effect of long-term methamphetamine (MAP) treatment on intracranial self-stimulation of the lateral hypotholamus and locomotor traces was assessed. An attempt was made to provide a useful animal model for understanding anhedonia, stereotypy, and reoccurrence of liability, which are analogous to symptoms of schizophrenia. The frequency of intracranial self-stimulation (ICSS) as used as a measure of the animals' "hedonic–anhedonic" state. Following long-term MAP treatment (3 mg/kg), rats gradually showed stereotyped behavior, and became inactive and unresponsive to ICSS. These behavioral changes and decreased ICSS lasted several weeks after cessation of chronic MAP treatment and seemed to suggest post-MAP chronic psychosis and (or) anhedonia, two of the negative symptoms of schizophrenia. The traces of rat behavior affected by chronic MAP treatment were classified into three types, peripheral, mixed, and fixed, occurring in a dose-dependent manner. Reverse tolerance, similar to the reoccurrence of schizophrenic symptoms, was observed as a fixed stereotypy associated with loss of ICSS. These abnormal phenomena were suppressed by pretreatment with haloperidol. In the present study, the combination of ICSS and locomotor trace affected by chronic MAP treatment was proposed as an animal model of schizophrenia and as a useful technique for gauging the effect of neuroleptics.Key words: self-stimulation, anhedonia, stereotypy, reverse tolerance, animal disease model, schizophrenia, methamphetamine.

scholarly journals NEMO-Binding Domain Peptide Attenuates Lipopolysaccharide-Induced Acute Lung Injury by Inhibiting the NF-κB Signaling Pathway

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Jianhua Huang ◽  
Li Li ◽  
Weifeng Yuan ◽  
Linxin Zheng ◽  
Zhenhui Guo ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Signaling Pathway ◽  
Binding Domain ◽  
Dependent Manner ◽  
Protective Effects ◽  
Lps Challenge ◽  
Domain Peptide ◽  
Nemo Binding Domain ◽  
Dose Dependent

The aim of the present study is to investigate the protective effects and relevant mechanisms exerted by NEMO-binding domain peptide (NBD) against lipopolysaccharide- (LPS-) induced acute lung injury (ALI) in mice. The ALI model was induced by intratracheally administered atomized LPS (5 mg/kg) to BABL/c mice. Half an hour before LPS administration, we treated the mice with increasing concentrations of intratracheally administered NBD or saline aerosol. Two hours after LPS administration, each group of mice was sacrificed. We observed that NBD pretreatment significantly attenuated LPS-induced lung histopathological injury in a dose-dependent manner. Western blotting established that NBD pretreatment obviously attenuated LPS-induced IκB-αand NF-κBp65 activation and NOX1, NOX2, and NOX4 overexpression. Furthermore, NBD pretreatment increased SOD and T-AOC activity and decreased MDA levels in lung tissue. In addition, NBD also inhibited TNF-αand IL-1βsecretion in BALF after LPS challenge. In conclusion, NBD protects against LPS-induced ALI in mice.

Prostaglandin E2 interaction with AVP: effects on AQP2 phosphorylation and distribution

2000 ◽  
Vol 278 (3) ◽  
pp. F388-F394 ◽  
Author(s):  
Marina Zelenina ◽  
Birgitte Mønster Christensen ◽  
Johan Palmér ◽  
Angus C. Nairn ◽  
Søren Nielsen ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Subcellular Distribution ◽  
Collecting Duct ◽  
Water Channel ◽  
Prostaglandin E ◽  
Dependent Manner ◽  
Centrifugation Technique ◽  
Renal Inner Medulla ◽  
Intracellular Vesicles ◽  
Dose Dependent

Prostaglandin E2 (PGE2) antagonizes the action of arginine vasopressin (AVP) on collecting duct water permeability. To investigate the mechanism of this antagonism, rat renal inner medulla (IM) was incubated with the two hormones, and the phosphorylation and subcellular distribution of the water channel, aquaporin-2 (AQP2) were studied. Using a phosphorylation state-specific AQP2 antibody, we demonstrated that AVP stimulates AQP2 phosphorylation at the Ser256 protein kinase A consensus site in a time- and dose-dependent manner. In parallel studies using a differential centrifugation technique, we demonstrated that AVP induced translocation of AQP2 from an intracellular vesicle-enriched fraction to a plasma membrane-enriched fraction. PGE2(10− 7 M) added after AVP (10− 8 M) did not decrease AQP2 phosphorylation but reversed AVP-induced translocation of AQP2 to the plasma membrane. Preincubation of IM with PGE2 did not prevent the effects of AVP on AQP2 phosphorylation and trafficking. PGE2 alone did not influence AQP2 phosphorylation and subcellular distribution. Our data indicate that 1) recruitment of AQP2 to the plasma membrane and its retrieval to a pool of intracellular vesicles may be regulated independently, 2) PGE2 may counteract AVP action by activation of AQP2 retrieval, 3) dephosphorylation of AQP2 is not a prerequisite for its internalization.

scholarly journals 4035 Astrocyte LDLR-Related Protein 1 Increases Cytokine Sensitivity – The Role of Glia in Recovery after Brain Damage

2020 ◽  
Vol 4 (s1) ◽  
pp. 3-3
Author(s):  
Sadiya Ahmad ◽  
Pamela Reed ◽  
Shane Sprauge ◽  
Naomi Sayre
Keyword(s):  
Plasma Membrane ◽  
Treatment Options ◽  
Significant Loss ◽  
Null Mouse ◽  
Dependent Manner ◽  
Related Protein ◽  
Stroke Patients ◽  
Term Outcome ◽  
Long Term Outcome

OBJECTIVES/GOALS: The limited treatment options for ischemic stroke patients have resulted in stroke being a leading cause of death and the primary cause of long-term disability in the U.S. Finding effective treatment options requires a better fundamental understanding of the ongoing processes that contribute to poor long-term outcome. METHODS/STUDY POPULATION: Expression of Apolipoprotein E4 predisposes stroke patients to poor long-term outcome. This study aims to test one possible mechanism by which ApoE4 contributes to cognitive decline after stroke. Here, we examine the effect of a major ApoE4 receptor, low-density lipoprotein receptor related protein 1 (LRP1) on sensitivity to stress in astrocytes. LRP1 binds and moves extracellular ligands and plasma membrane proteins into the endocytic system. Others have shown that LRP1 regulates cell-surface TNF receptor (TNFR1) in non-astrocytic cells. We propose That LRP1 similarly regulates TNFR1 in the central nervous system to attenuate inflammatory response after stroke. Studies have shown that ApoE4 slows the recycling of endocytic LDL receptors. We hypothesize that ApoE4 inhibits the ability of LRP1 to remove TNFR1 from the plasma membrane. This is expected to increase cytokine sensitivity, resulting in worse outcome after stroke. We investigated the effect of LRP1 on astrocyte TNFα signaling and response in immortalized ApoE null mouse astrocytes subjected to lentiviral-mediated knockdown of LRP1. The astrocyte response to TNFα stimulation was tested in a time dependent manner using Western blotting of NFkB pathway components, which are the downstream mediators of TNFα signaling. We also tested astrocyte viability after prolonged TNFα stimulation using Alamar Blue reagent. We found that LRP1 deficient cells have increased phosphorylation of NFkB upon TNFα stimulation, and that loss of LRP1 resulted in significant loss of astrocyte viability after prolonged stimulation. RESULTS/ANTICIPATED RESULTS: Altogether, our results indicate that loss of LRP1 renders astrocytes more sensitive to TNFα. Future experiments will focus on testing the influence of LRP1 on recovery after middle cerebral artery occlusion in mice. DISCUSSION/SIGNIFICANCE OF IMPACT: These studies will elucidate how astrocyte-LRP1 contributes to outcome after stroke, and helps us to understand one potential way that ApoE4 exerts pathological effects. A better understanding of the long-term processes after stroke will allow identification of therapies which improve the morbidity and mortality associated with stroke. CONFLICT OF INTEREST DESCRIPTION: NA.

Rapamycin inhibits the growth of cholangiocarcinoma cells in vitro

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 15153-15153 ◽  
Author(s):  
T. Sawada ◽  
T. Okada ◽  
K. Kubota
Keyword(s):  
Synergistic Effect ◽  
Cell Lines ◽  
Mtt Assay ◽  
Mrna Level ◽  
Dependent Manner ◽  
In Vitro Methods ◽  
Proliferative Effect ◽  
Cholangiocarcinoma Cell ◽  
Dose Dependent

15153 Background: In the present study, anti-neoplastic effect of rapamycin against cholangiocarcinoma was studied in vitro. Methods: Expression of mTOR in 4 cholangiocarcinoma cell lines, TFK1, HuCCT1, NOZW, and OZ was evaluated by real-time PCR. Then, the four cholangiocarcinoma cell lines were cultured with rapamycin (0, 25, 50, 100, 200 nM), gemcitabine (0, 0.5, 1, 2 μM), or both, and anti-proliferative effect was evaluated by MTT assay. Results: All the four cholangiocarcinoma cell lines expressed endogenous mTOR- mRNA. Level of expression was the highest in HuCCT1 (65.8), and the lowest in TFK1 (17.6). Then, rapamycin significantly inhibited the growth of all the four cholangiocarcinoma cell lines, in dose-dependent manner. Gemcitabine inhibited the growth of NOZW (48.4%) and HuCCT1 (48.9%), but less efficiently in TFK1 (5.9%) and OZ (27.4%). Furthermore, synergistic anti-proliferative effect of rapamycin and gemcitabine was observed in TFK1 (39.1%), NOZW (38.9%), and OZ (47.1%), not in HuCCT1 (18.9%). Conclusion: Rapamycin effectively inhibited the growth of the cholangiocarcinoma cell lines, and synergistic effect with gemcitabine was observed in three of the four cell lines. No significant financial relationships to disclose.

Effect of retinoic acid on limb regeneration in Xenopus laevis

1983 ◽  
Vol 61 (12) ◽  
pp. 2698-2702 ◽  
Author(s):  
Steven R. Scadding
Keyword(s):  
Retinoic Acid ◽  
Xenopus Laevis ◽  
Limb Regeneration ◽  
Dependent Manner ◽  
African Clawed Frog ◽  
Long Term Effect ◽  
Aquarium Water ◽  
Dose Dependent ◽  
Clawed Frog

The objective of this experiment was to determine the effect of retinoic acid on the process of limb regeneration in the African clawed frog, Xenopus laevis. Limbs were bilaterally amputated through the radio-ulna and then treated for 15 days with retinoic acid in the aquarium water, at 3, 15, or 75 IU/mL. The retinoic acid inhibited limb regeneration in a dose-dependent manner, reduced the length of the regenerates, and produced irregularities in the morphogenesis of the cartilage rod in the regenerate. The regenerated limbs were removed after 150 days by amputation through the humerus, and the limbs were again allowed to regenerate. In the retinoic acid treated animals, despite the fact that retinoic acid treatment had been discontinued over 4 months previously, limb regeneration was still inhibited. These results suggest that retinoic acid has a long-term effect on the treated animals.

scholarly journals Activation Effects of Polysaccharides ofFlammulina velutipesMycorrhizae on the T Lymphocyte Immune Function

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Zheng-Fei Yan ◽  
Nai-Xu Liu ◽  
Xin-Xin Mao ◽  
Yu Li ◽  
Chang-Tian Li
Keyword(s):  
Immune Function ◽  
T Lymphocyte ◽  
Interleukin 2 ◽  
Potential Effect ◽  
Dependent Manner ◽  
Health Products ◽  
Immune Health ◽  
Spleen Lymphocytes ◽  
Dose Dependent

Flammulina velutipesmycorrhizae have increasingly been produced with increasing ofF. velutipesproduction. A mouse model was thus used to examine potential effect ofF. velutipesmycorrhizae on the immune function. Fifty female Wistar mice (5-weeks-old) weighed 15–20 g were randomly allocated into five groups. Polysaccharide ofF. velutipesmycorrhizae were treated with mice and mice spleen lymphocytes. The levels of CD3+, CD4+, and CD8+T lymphocyte, interleukin-2 (IL-2), and tumor necrosis factor-a (TNF-α) were determined. The results showed that the proportions of CD3+, and CD4+T lymphocyte, the ratio of CD4+/CD8+, and the levels of IL-2 and TNF-a were significantly increased in polysaccharide ofF. velutipesmycorrhizae, while the proportion of CD8+T lymphocyte was decreased in polysaccharide ofF. velutipesmycorrhizae-dose dependent manner. Our findings indicated that a long term exposure of polysaccharide ofF. velutipesmycorrhizae could activate the T lymphocyte immune function. Polysaccharide ofF. velutipesmycorrhizae was expected to develop into the immune health products.

scholarly journals Dual effects of presynaptic membrane mimetics on α-synuclein amyloid aggregation

2021 ◽  
Author(s):  
Yuxi Lin ◽  
Dai Ito ◽  
Je Min Yoo ◽  
Mi Hee Lim ◽  
Woo Kyung Yu ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Structural Changes ◽  
Dependent Manner ◽  
Binding Properties ◽  
Intrinsically Disordered ◽  
Membrane Surfaces ◽  
Amyloid Fibrillation ◽  
Presynaptic Vesicle ◽  
Helical Folding ◽  
Dose Dependent

Aggregation of intrinsically disordered α-synuclein (αSN) under various conditions is closely related to synucleinopathies. Although various biological membranes have shown to alter the structure and aggregation propensity of αSN, a thorough understanding of the molecular and mechanical mechanism of amyloidogenesis in membranes remains unanswered. Herein, we examined the structural changes, binding properties, and amyloidogenicity of three variations of αSN mutants under two types of liposomes, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and presynaptic vesicle mimetic (Mimic) membranes. While neutrally charged DOPC membranes elicited marginal changes in the structure and amyloid fibrillation of αSNs, negatively charged Mimic membranes induced dramatic helical folding and biphasic amyloid generation. At low concentration of Mimic membranes, the amyloid fibrillation of αSNs was promoted in a dose-dependent manner. However, further increases in the concentration constrained the fibrillation process. These results suggest the dual effect of Mimic membranes on regulating the amyloidogenesis of αSN, which is rationalized by the amyloidogenic structure of αSN and condensation-dilution of local αSN concentration. Finally, we propose physicochemical properties of αSN and membrane surfaces, and their propensity to drive electrostatic interactions as decisive factors of amyloidogenesis.

scholarly journals Anticonvulsant effects of nimodipine alone and combination with phenytoin on MES induced seizures

2018 ◽  
Vol 7 (6) ◽  
pp. 1160
Author(s):  
Raina Jain ◽  
Ashish Jain
Keyword(s):  
Synergistic Effect ◽  
Anticonvulsant Activity ◽  
Hind Limb ◽  
Channel Blockers ◽  
Dependent Manner ◽  
The Novel ◽  
Antiepileptic Activity ◽  
Effective Doses ◽  
Dose Dependent ◽  
Anticonvulsant Effects

Background: To evaluate the anticonvulsant activity of Nimodipine alone and in combination with Phenytoin, in MES induced seizures.Methods: The study was conducted in mice and MES seizure was induced by Techno electroconvulsometer. In first part of study, animals were treated with Nimodipine (20mg/kg i.p. and 40mg/kg i.p.) and Phenytoin (0.5 mg/100g i.p. and 1.0mg/100g i.p.), MES was induced and durations of various phases were noted. Duration of Tonic hind limb extension (THLE) was taken as index for antiepileptic activity. In second part, the animals were treated with combination of sub effective doses of Nimodipine (20mg/kg i.p.) and Phenytoin (0.5mg/100g i.p.), MES was induced and durations of various phases were noted.Results: Nimodipine produced significant antiepileptic activity, in dose dependent manner. Phenytoin produced significant antiepileptic effect in dose of 1.0mg/100g but failed to produce any such effect in dose of 0.5mg/100g, when administered alone. But when sub effective doses.Of Nimodipine and Phenytoin were combined, a synergistic effect was seen.Conclusions: Nimodipine possess significant antiepileptic activity, alone, as well as it potentiates the antiepileptic effect of Phenytoin, suggesting the novel application of already proven safe and efficacious calcium channel blockers.

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