Millipore Sigma Vibrant Logo
 

caffeine


78 Results Búsqueda avanzada  
Mostrar
Productos (7)
Documentos (54)
Páginas (17)

Acote sus resultados Utilice los filtros siguientes para refinar su búsqueda

Tipo de documento

  • (40)
  • (11)
  • (2)
  • (1)
¿No encuentra lo que está buscando?
Póngase en contacto con
el Servicio de Atención
al Cliente

 
¿Necesita ayuda para encontrar un documento?

  • Caffeine activates preferentially alpha1-isoform of 5'AMP-activated protein kinase in rat skeletal muscle. 20645930

    Abstract Aim: Caffeine activates 5'AMP-activated protein kinase (AMPK), a signalling intermediary implicated in the regulation of glucose, lipid, and energy metabolism in skeletal muscle. Skeletal muscle expresses two catalytic alpha subunits of AMPK, alpha1 and alpha2, but the isoform specificity of caffeine-induced AMPK activation is unclear. The aim of this study was to determine which alpha isoform is preferentially activated by caffeine in vitro and in vivo using rat skeletal muscle. Methods: Rat epitrochlearis muscle was isolated and incubated in vitro in the absence or presence of caffeine. In another experiment, the muscle was dissected after intravenous injection of caffeine. Isoform-specific AMPK activity, the phosphorylation status of AMPKalpha Thr(172) and acetyl-CoA carboxylase (ACC) Ser(79), the concentrations of ATP, phosphocreatine (PCr), and glycogen, and 3-O-methyl-d-glucose (3MG) transport activity were estimated. Results: Incubation of isolated epitrochlearis muscle with 1 mM of caffeine for 15 min increased AMPKalpha1 activity, but not AMPKalpha2 activity; concentrations of ATP, PCr and glycogen were not affected. Incubation with 3 mM of caffeine activated AMPKalpha2 and reduced PCr and glycogen concentrations. Incubation with 1 mM of caffeine increased the phosphorylation of AMPK and ACC and enhanced 3MG transport. Intravenous injection of caffeine (5 mg kg(-1)) predominantly activated AMPKalpha1 and increased 3MG transport without affecting energy status. Conclusion: Our results suggest that of the two alpha isoforms of AMPK, AMPKalpha1 is predominantly activated by caffeine via an energy-independent mechanism and that activation of AMPKalpha1 increases glucose transport and ACC phosphorylation in skeletal muscle.
    Tipo de documento:
    Referencia
    Referencia del producto:
    07-303
    Nombre del producto:
    Anti-phospho-Acetyl CoA Carboxylase (Ser79) Antibody

  • Caffeine promotes glutamate and histamine release in the posterior hypothalamus. 25031227

    Histamine neurons are active during waking and largely inactive during sleep, with minimal activity during rapid-eye movement (REM) sleep. Caffeine, the most widely used stimulant, causes a significant increase of sleep onset latency in rats and humans. We hypothesized that caffeine increases glutamate release in the posterior hypothalamus (PH) and produces increased activity of wake-active histamine neurons. Using in vivo microdialysis, we collected samples from the PH after caffeine administration in freely behaving rats. HPLC analysis and biosensor measurements showed a significant increase in glutamate levels beginning 30 min after caffeine administration. Glutamate levels remained elevated for at least 140 min. GABA levels did not significantly change over the same time period. Histamine level significantly increased beginning 30 min after caffeine administration and remained elevated for at least 140 min. Immunostaining showed a significantly elevated number of c-Fos-labeled histamine neurons in caffeine-treated rats compared with saline-treated animals. We conclude that increased glutamate levels in the PH activate histamine neurons and contribute to caffeine-induced waking and alertness.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AB176

  • Proliferation inhibition, DNA damage, and cell-cycle arrest of human astrocytoma cells after acrylamide exposure. 20734998

    Acrylamide (ACR) has been recognized as a neurological and reproductive toxin in humans and laboratory animals. This study aimed to determine the effects of ACR-induced DNA damage on cell cycle regulation in human astrocytoma cell lines. Treatment of U-1240 MG cells with 2 mM ACR for 48 h resulted in a significant inhibition of cell proliferation as evaluated by Ki-67 protein expression and MTT assay. The analysis of DNA damage with the comet assay showed that treatment of the cells with 0.5, 1, and 2 mM ACR for 48 h caused significant increases in DNA damage by 3.5-, 4-, and 14-fold, respectively. Meanwhile, analysis of cell-cycle arrest with flow cytometry revealed that the ACR treatments resulted in significant increases in the G(0)/G(1)-arrested cells in a time- and dose-dependent manner. Expression of DNA damage-associated/checkpoint-related signaling molecules, including phosphorylated-p53 (pp53), p53, p21, p27, Cdk2, and cyclin D(1), in three human astrocytoma cell lines (U-1240 MG, U-251 MG, and U-87 MG) was also analyzed by immunoblotting. Treatment of the three cell lines with 2 mM ACR for 48 h caused marked increases in pp53 and Cdk2, as well as decreases in cyclin D(1) and p27. Moreover, increases in p53 and p21 were detected in both U-1240 and U-87 MG cells, whereas no marked change in p53 and a decrease in p21 were observed in U-251 MG cells. To address the involvement of ataxia telangiectasia mutated/ATM-Rad3-related (ATM/ATR) kinase in the signaling of ACR-induced G(0)/G(1) arrest, caffeine was used to block the ATM/ATR pathway in U-1240 MG cells. Caffeine significantly attenuated the ACR-induced G(0)/G(1) arrest as well as the expression of DNA damage-associated/checkpoint-related signaling molecules in a dose-dependent manner. This in vitro study clearly demonstrates the critical role of ATM/ATR in the signaling of ACR-induced cell-cycle arrest in astrocytoma cells.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB3402
    Nombre del producto:
    Anti-Glial Fibrillary Acidic Protein Antibody, clone GA5

  • Caffeine acutely activates 5'adenosine monophosphate-activated protein kinase and increases insulin-independent glucose transport in rat skeletal muscles. 19608206

    Caffeine (1,3,7-trimethylxanthine) has been implicated in the regulation of glucose and lipid metabolism including actions such as insulin-independent glucose transport, glucose transporter 4 expression, and fatty acid utilization in skeletal muscle. These effects are similar to the exercise-induced and 5'adenosine monophosphate-activated protein kinase (AMPK)-mediated metabolic changes in skeletal muscle, suggesting that caffeine is involved in the regulation of muscle metabolism through AMPK activation. We explored whether caffeine acts on skeletal muscle to stimulate AMPK. Incubation of rat epitrochlearis and soleus muscles with Krebs buffer containing caffeine (> or =3 mmol/L, > or =15 minutes) increased the phosphorylation of AMPKalpha Thr(172), an essential step for full kinase activation, and acetyl-coenzyme A carboxylase Ser(79), a downstream target of AMPK, in dose- and time-dependent manners. Analysis of isoform-specific AMPK activity revealed that both AMPKalpha1 and alpha2 activities increased significantly. This enzyme activation was associated with a reduction in phosphocreatine content and an increased rate of 3-O-methyl-d-glucose transport activity in the absence of insulin. These results suggest that caffeine has similar actions to exercise by acutely stimulating skeletal muscle AMPK activity and insulin-independent glucose transport with a reduction of the intracellular energy status.,
    Tipo de documento:
    Referencia
    Referencia del producto:
    07-303
    Nombre del producto:
    Anti-phospho-Acetyl CoA Carboxylase (Ser79) Antibody

  • Caffeine - 19565

    Tipo de documento:
    Certificado de análisis
    Número de lote:
    19565
    Referencia del producto:
    19-156

  • Neuroprotective and anti-inflammatory properties of a coffee component in the MPTP model of Parkinson's disease. 23296837

    Consumption of coffee is associated with reduced risk of Parkinson's disease (PD), an effect that has largely been attributed to caffeine. However, coffee contains numerous components that may also be neuroprotective. One of these compounds is eicosanoyl-5-hydroxytryptamide (EHT), which ameliorates the phenotype of α-synuclein transgenic mice associated with decreased protein aggregation and phosphorylation, improved neuronal integrity and reduced neuroinflammation. Here, we sought to investigate if EHT has an effect in the MPTP model of PD. Mice fed a diet containing EHT for four weeks exhibited dose-dependent preservation of nigral dopaminergic neurons following MPTP challenge compared to animals given control feed. Reductions in striatal dopamine and tyrosine hydroxylase content were also less pronounced with EHT treatment. The neuroinflammatory response to MPTP was markedly attenuated, and indices of oxidative stress and JNK activation were significantly prevented with EHT. In cultured primary microglia and astrocytes, EHT had a direct anti-inflammatory effect demonstrated by repression of lipopolysaccharide-induced NFκB activation, iNOS induction, and nitric oxide production. EHT also exhibited a robust anti-oxidant activity in vitro. Additionally, in SH-SY5Y cells, MPP(+)-induced demethylation of phosphoprotein phosphatase 2A (PP2A), the master regulator of the cellular phosphoregulatory network, and cytotoxicity were ameliorated by EHT. These findings indicate that the neuroprotective effect of EHT against MPTP is through several mechanisms including its anti-inflammatory and antioxidant activities as well as its ability to modulate the methylation and hence activity of PP2A. Our data, therefore, reveal a strong beneficial effect of a novel component of coffee in multiple endpoints relevant to PD.
    Tipo de documento:
    Referencia
    Referencia del producto:
    06-222
    Nombre del producto:
    Anti-PP2A Antibody, C subunit

  • Caffeine consumption prevents diabetes-induced memory impairment and synaptotoxicity in the hippocampus of NONcZNO10/LTJ mice. 22514596

    Diabetic conditions are associated with modified brain function, namely with cognitive deficits, through largely undetermined processes. More than understanding the underlying mechanism, it is important to devise novel strategies to alleviate diabetes-induced cognitive deficits. Caffeine (a mixed antagonist of adenosine A(1) and A(2A) receptors) emerges as a promising candidate since caffeine consumption reduces the risk of diabetes and effectively prevents memory deficits caused by different noxious stimuli. Thus, we took advantage of a novel animal model of type 2 diabetes to investigate the behavioural, neurochemical and morphological modifications present in the hippocampus and tested if caffeine consumption might prevent these changes. We used a model closely mimicking the human type 2 diabetes condition, NONcNZO10/LtJ mice, which become diabetic at 7-11 months when kept under an 11% fat diet. Caffeine (1 g/l) was applied in the drinking water from 7 months onwards. Diabetic mice displayed a decreased spontaneous alternation in the Y-maze accompanied by a decreased density of nerve terminal markers (synaptophysin, SNAP25), mainly glutamatergic (vesicular glutamate transporters), and increased astrogliosis (GFAP immunoreactivity) compared to their wild type littermates kept under the same diet. Furthermore, diabetic mice displayed up-regulated A(2A) receptors and down-regulated A(1) receptors in the hippocampus. Caffeine consumption restored memory performance and abrogated the diabetes-induced loss of nerve terminals and astrogliosis. These results provide the first evidence that type 2 diabetic mice display a loss of nerve terminal markers and astrogliosis, which is associated with memory impairment; furthermore, caffeine consumption prevents synaptic dysfunction and astrogliosis as well as memory impairment in type 2 diabetes.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AB5905
    Nombre del producto:
    Anti-Vesicular Glutamate Transporter 1 Antibody

  • Caffeine regulates frontocorticostriatal dopamine transporter density and improves attention and cognitive deficits in an animal model of attention deficit hyperactivity ... 22561003

    Attention deficit hyperactivity disorder (ADHD) likely involves dopaminergic dysfunction in the frontal cortex and striatum, resulting in cognitive and motor abnormalities. Since both adenosine and dopamine modulation systems are tightly intertwined, we tested if caffeine (a non-selective adenosine receptor antagonist) attenuated the behavioral and neurochemical changes in adolescent spontaneously hypertensive rats (SHR, a validated ADHD animal model) compared to their control strain (Wistar Kyoto rats, WKY). SHR were hyperactive and had poorer performance in the attentional set-shifting and Y-maze paradigms and also displayed increased dopamine transporter (DAT) density and increased dopamine uptake in frontocortical and striatal terminals compared with WKY rats. Chronic caffeine treatment was devoid of effects in WKY rats while it improved memory and attention deficits and also normalized dopaminergic function in SHR. Additionally, we provide the first direct demonstration for the presence of adenosine A(2A) receptors (A(2A)R) in frontocortical nerve terminals, whose density was increased in SHR. These findings underscore the potential for caffeine treatment to normalize frontocortical dopaminergic function and to abrogate attention and cognitive changes characteristic of ADHD.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB369
    Nombre del producto:
    Anti-Dopamine Transporter Antibody, NT, clone DAT-Nt

  • Mutations in PNKD causing paroxysmal dyskinesia alters protein cleavage and stability. 21487022

    Paroxysmal non-kinesigenic dyskinesia (PNKD) is a rare autosomal dominant movement disorder triggered by stress, fatigue or consumption of either alcohol or caffeine. Attacks last 1-4 h and consist of dramatic dystonia and choreoathetosis in the limbs, trunk and face. The disease is associated with single amino acid changes (A7V or A9V) in PNKD, a protein of unknown function. Here we studied the stability, cellular localization and enzymatic activity of the PNKD protein in cultured cells and transgenic animals. The N-terminus of the wild-type (WT) long PNKD isoform (PNKD-L) undergoes a cleavage event in vitro, resistance to which is conferred by disease-associated mutations. Mutant PNKD-L protein is degraded faster than the WT protein. These results suggest that the disease mutations underlying PNKD may disrupt protein processing in vivo, a hypothesis supported by our observation of decreased cortical Pnkd-L levels in mutant transgenic mice. Pnkd is homologous to a superfamily of enzymes with conserved β-lactamase domains. It shares highest homology with glyoxalase II but does not catalyze the same reaction. Lower glutathione levels were found in cortex lysates from Pnkd knockout mice versus WT littermates. Taken together, our results suggest an important role for the Pnkd protein in maintaining cellular redox status.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB374
    Nombre del producto:
    Anti-Glyceraldehyde-3-Phosphate Dehydrogenase Antibody, clone 6C5