AMP Content Research Articles

In silico study of protein to protein interaction analysis of AMP-activated protein kinase and mitochondrial activity in three different farm animal species

AMP-activated protein kinase (AMPK) is cellular energy censor which works based on ATP and AMP concentration. This protein interacts with mitochondria in determine its activity to generate energy for cell metabolism purposes. For that, this paper aims to compare the protein to protein interaction of AMPK and mitochondrial activity genes in the metabolism of known animal farm (domesticated) that are cattle (Bos taurus), pig (Sus scrofa) and chicken (Gallus gallus). In silico study was done using STRING V.10 as prominent protein interaction database, followed with biological function comparison in KEGG PATHWAY database. Set of genes (12 in total) were used as input analysis that are PRKAA1, PRKAA2, PRKAB1, PRKAB2, PRKAG1, PRKAG2, PRKAG3, PPARGC1, ACC, CPT1B, NRF2 and SOD. The first 7 genes belong to gene in AMPK family, while the last 5 belong to mitochondrial activity genes. The protein interaction result shows 11, 8 and 5 metabolism pathways in Bos taurus, Sus scrofa and Gallus gallus, respectively. The top pathway in Bos taurus is AMPK signaling pathway (10 genes), Sus scrofa is Adipocytokine signaling pathway (8 genes) and Gallus gallus is FoxO signaling pathway (5 genes). Moreover, the common pathways found in those 3 species are Adipocytokine signaling pathway, Insulin signaling pathway and FoxO signaling pathway. Genes clustered in Adipocytokine and Insulin signaling pathway are PRKAA2, PPARGC1A, PRKAB1 and PRKAG2. While, in FoxO signaling pathway are PRKAA2, PRKAB1, PRKAG2. According to that, we found PRKAA2, PRKAB1 and PRKAG2 are the common genes. Based on the bioinformatics analysis, we can demonstrate that protein to protein interaction shows distinct different of metabolism in different species. However, further validation is needed to give a clear explanation.

Identification of Clustered Phosphorylation Sites in PKD2L1: How PKD2L1 Channel Activation is Regulated by Cyclic AMP Signaling Pathway

Polycystic kidney disease 2-like-1 (PKD2L1), or polycystin-L or TRPP2, formerly TRPP3, is a transient receptor potential (TRP) superfamily member. It is a calcium-permeable non-selective cation channel that regulates intracellular calcium concentration and thereby calcium signaling. PKD2L1 has been reported to take part in hedgehog signaling in renal primary cilia and sour tasting coupling with PKD1L3. In addition to the previous reports, PKD2L1 is recently found to play a crucial role in localization with β2-adrenergic receptor (β2AR) on the neuronal primary cilia. The disruption of PKD2L1 leads to the loss of β2AR on the primary cilia and reduction in intracellular concentration of cyclic AMP (cAMP). Since the role of cAMP and PKA is frequently studied in relation to PKD diseases, we investigated on the mechanism of cAMP regulation in relation to the function of PKD2L1 channel. In this study, we observed the activity of PKD2L1 channel increased by the downstream cascades of β2AR and found the clustered phosphorylation sites, S682, S685, and S686 that are significant in the channel regulation by phosphorylation.

Kinetics of CO2 Absorption into Aqueous AMP/HMDA/TEG Mixtures

AbstractMixtures of 2‐amino‐2‐methyl‐1‐propanol (AMP), 1,6‐hexamethyl diamine (HMDA), triethylene glycol (TEG) and water, which merge the loading capacity of AMP, reactivity of HMDA and low volatility of TEG, are improved CO2‐capturing solvents. In the present study, kinetic aspects of the reaction of CO2 with the blend AMP+HMDA were investigated using co‐solvents TEG+Water. Kinetic data were experimentally obtained in a stirred cell at 303–318 K. The concentrations of AMP and HMDA in the mixtures were changed in the 2–3 and 0.1‐0.5 M range whereas TEG concentration was changed between 0.7 and 2 M. Pseudo‐first order rate constants were measured. Knowing the CO2 absorption rates in the aforesaid mixtures, the second‐order rate constant (65195 M−1 s−1) for the reaction between CO2 and HMDA at 308 K was found. The activation energy for the CO2‐HMDA system in aqueous solution was 33.1 kJ/mol. Equilibrium solubility of CO2 in AMP/HMDA/TEG/Water mixtures was measured. Finally, it was established that N,N’‐dimethyl‐1,6‐hexamethyl diamine (or HMDA−N,N’) – a dialkyl derivative of HMDA – is a further attractive promoter for AMP in TEG+Water mixtures.

Determination of Adenine Nucleotide Concentrations in Cells and Tissues by High-Performance Liquid Chromatography.

The serine/threonine AMP-activated protein kinase (AMPK) is a central player in the regulation of energy homeostasis, and its activity is tightly controlled, among other mechanisms, by subtle changes in cellular adenine nucleotide levels. In this chapter, we describe a step-by-step protocol for rapid, highly sensitive, reproducible, and simultaneous determination of ATP, ADP, and AMP concentrations in cell or tissue samples by reversed-phase high-performance liquid chromatography (HPLC).

Histoprognostic Factors in Bladder Cancer: A Case Series of 156 Patients

Background: For a long time, phenomenon of defective immune-surveillance in cancer patients from pathological standpoint was not elucidated. I have reported 1985 that lowering seral cyclic AMP is biochemical reason of defective immunesurveillance from adoptive lymphocyte immunotherapy experiment among cancer patients. Recently, Honjo Tasku et al., reported why T cell don’t attack cancer cells by the covering of PD-L1 on its receptor of PD-1. This is also one of defective immune-surveillance from cellular side. I have recently surveyed the correlation between seral cyclic AMP concentration and immune activity in cancer patients. I have confirmed the biochemical reason of lowering cyclic AMP leads to seral defective immune-surveillance in cancer patient’s serum. Methods: I have surveyed seral cyclic AMP concentration and T cell number and NK cell among 40 cancer patients and preclinical cancer patients. Results: The averaged seral cyclic AMP has a positive tendency between lower immune activity and lower cyclic AMP in the serum when cancer is developing beforehand. Conclusion: As cyclic AMP is elevated after fasting therapy, adoptive lymphocyte immunotherapy become useful as immuno-potentiation even if in advanced cancer patients.

Protein Kinase A Distribution Differentiates Human Glioblastoma from Brain Tissue.

Brain tumor glioblastoma has no clear molecular signature and there is no effective therapy. In rodents, the intracellular distribution of the cyclic AMP (cAMP)-dependent protein kinase (Protein kinase A, PKA) R2Alpha subunit was previously shown to differentiate tumor cells from healthy brain cells. Now, we aim to validate this observation in human tumors. The distribution of regulatory (R1 and R2) and catalytic subunits of PKA was examined via immunohistochemistry and Western blot in primary cell cultures and biopsies from 11 glioblastoma patients. Data were compared with information obtained from 17 other different tumor samples. The R1 subunit was clearly detectable only in some samples. The catalytic subunit was variably distributed in the different tumors. Similar to rodent tumors, all human glioblastoma specimens showed perinuclear R2 distribution in the Golgi area, while it was undetectable outside the tumor. To test the effect of targeting PKA as a therapeutic strategy, the intracellular cyclic AMP concentration was modulated with different agents in four human glioblastoma cell lines. A significant increase in cell death was detected after increasing cAMP levels or modulating PKA activity. These data raise the possibility of targeting the PKA intracellular pathway for the development of diagnostic and/or therapeutic tools for human glioblastoma.

Evolution of the metabolome in response to selection for increased immunity in populations of Drosophila melanogaster.

We used NMR-based metabolomics to test two hypotheses–(i) there will be evolved differences in the metabolome of selected and control populations even under un-infected conditions and (ii) post infection, the metabolomes of the selected and control populations will respond differently. We selected replicate populations of Drosophila melanogaster for increased survivorship (I) against a gram-negative pathogen. We subjected the selected (I) and their control populations (S) to three different treatments: (1) infected with heat-killed bacteria (i), (2) sham infected (s), and (3) untreated (u). We performed 1D and 2D NMR experiments to identify the metabolic differences. Multivariate analysis of the metabolic profiles of the untreated (Iu and Su) flies yielded higher concentrations of lipids, organic acids, sugars, amino acids, NAD and AMP in the Iu treatment as compared to the Su treatment, showing that even in the absence of infection, the metabolome of the I and S regimes was different. In the S and I regimes, post infection/injury, concentration of metabolites directly or indirectly associated with energy related pathways (lipids, organic acids, sugars) declined while the concentration of metabolites that are probably associated with immune response (amino acids) increased. However, in most cases, the I regime flies had a higher concentration of such metabolites even under un-infected conditions. The change in the metabolite concentration upon infection/injury was not always comparable between I and S regimes (in case of lactate, alanine, leucine, lysine, threonine) indicating that the I and S regimes had evolved to respond differentially to infection and to injury.

Preslaughter Transport Effect on Broiler Meat Quality and Post-mortem Glycolysis Metabolism of Muscles with Different Fiber Types

Preslaughter transport has been reported to decrease the quality of breast meat but not thigh meat of broilers. However, tissue-specific difference in glycogen metabolism between breast and thigh muscles of transported broilers has not been well studied. We thus investigated the differences in meat quality, adenosine phosphates, glycolysis, and bound key enzymes associated with glycolysis metabolism in skeletal muscles with different fiber types of preslaughter transported broilers during summer. Compared to a 0.5 h transport, a 3 h transport during summer decreased ATP content, increased AMP content and AMP/ATP ratio, and accelerated glycolysis metabolism via the upregulation of glycogen phosphorylase expression accompanied by increased activities of bound glycolytic enzymes (hexokinase, pyruvate kinase, and lactate dehydrogenase) in pectoralis major muscle, which subsequently increased the likelihood of pale, soft, and exudative-like breast meat. On the other hand, a 3 h transport induced only a moderate glycolysis metabolism in tibialis anterior muscle, which did not cause any noticeable changes in the quality traits of the thigh meat.

Action mechanism of acupuncture along meridians on improving energy metabolism in cardiomyocytes

To explore the protective effect of acupuncture along meridians on rats with myocardial ischemia and its effect and action mechanism on cardiomyocyte energy metabolism. A total of 104 healthy 12-week-old SD rats were fed adaptively for 1 week and included into study with no disease symptoms observed. Of them, 24 SD rats were selected regardless of gender, and were randomly divided into a blank group and a sham operation group, 12 rats in each one. The remaining 80 SD rats were treated with ligation of left anterior descending coronary artery to establish the model of myocardial ischemia. The successful rate of model establishment was 60%, and 48 rats survived. They were randomly divided into a model group, an acupuncture along meridian group, an acupuncture along another-meridian group and a non-acupoint group, 12 rats in each one. The blank group was not treated with operation, but only bundle fixation. The sham operation group was treated with sham operation (coronary artery was not ligatured). The model group bundle fixation. The acupuncture along meridian group were treated with electroacupuncture (EA) at "Neiguan" (PC 6), the acupuncture along another-meridian group were treated with EA at "Hegu" (LI 4), and the non-acupoints group were treated at a non-acupoint which located in the hollow of the 3rd and 4th metatarsal bones of the dorsal foot of fore rate limb. Each bundle fixation or EA was given for 30 min, once a day for consecutive 5 days. The electrocardiogram was tested in all groups; the apoptosis rate of cardiomyocytes was detected by Tunel; the contents of ATP, ADP and AMP in myocardium were detected by high performance liquid chromatography. The ST segment voltage after model establishment was higher than that before modeling (all P<0.05). Compared with the model group after intervention, the ST segment was elevated in the acupuncture along meridian group, acupuncture along another-meridian group and non-acupoint group (P<0.01, P<0.05), but the apoptosis rate of cardiomyocytes was significantly reduced (all P<0.01). Compared with the acupuncture along another-meridian group and non-acupoint group, the apoptosis rate of cardiomyocytes in the acupuncture along meridian group was significantly decreased (both P<0.01). Compared with the model group after intervention, the content of ATP was increased in acupuncture along meridian group (P<0.05); compared with the non-acupoint group, the content of ATP was increased in the acupuncture along meridian group (P<0.05); compared with the model group, the contents of ADP and AMP were reduced in the acupuncture along meridian group, acupuncture along another-meridian group and non-acupoint group (all P<0.05); the energy charge EC in the acupuncture along meridian group was higher than that in the model group (P<0.05). Acupuncture along meridians can effectively relieve the damage of cardiac muscle tissue; the possible mechanism is to increase ATP and reduce ADP, AMP of cardiomyocytes, so EC level is elevated and myocardial cell apoptosis is inhibited, leading to protective effect on cardiac muscle tissue and cells.

Absorption heat, solubility, absorption and desorption rates, cyclic capacity, heat duty, and absorption kinetic modeling of AMP–DETA blend for post–combustion CO2 capture

Abstract This study investigated the absorption heat, equilibrium CO2 solubility, absorption and desorption rates, cyclic capacities, heat duty, and absorption kinetic modeling of amine blends containing AMP and DETA. The AMP and DETA concentrations were varied (1–2.5 kmol/m3 and 0.5–2 kmol/m3, respectively) while the total amine concentration was constant at 3 kmol/m3. The absorption experiment was conducted at 15 %v/v CO2 and 313 K while the desorption temperature was at 363 K. Experimental results revealed that the absorption rates, cyclic capacities and desorption rates of some AMP–DETA blends were higher than those of 5 kmol/m3 MEA. The absorption heat of the blends is comparable to that of MEA while the heat duty of some AMP–DETA blends are much lower than that of 5 kmol/m3 MEA. The optimal amine blend was confirmed to be 2 kmol/m3 AMP – 1 kmol/m3 DETA. A model similar to the power law kinetic model showed that CO2 composition in the feed gas affected the initial absorption rates as compared to AMP/DETA molar concentration ratio. The model predicted the initial absorption rate with a %AAD of 0.52%. These results provide good prospects for AMP–DETA blends towards CO2 capture.

Blue whiting (Micromesistius poutassou) muscle protein hydrolysate with in vitro and in vivo antidiabetic properties

A blue whiting (Micromesistius poutassou) protein hydrolysate generated using Alcalase 2.4L and Flavourzyme 500L and its simulated gastrointestinal digestion (SGID) sample was assessed for antidiabetic potential in vitro and in vivo. In addition to inhibiting dipeptidyl peptidase-IV (DPP–IV), the hydrolysates mediated insulin and glucagon-like peptide-1 (GLP-1) release from BRIN-BD11 and GLUTag cells, respectively. No significant difference was observed in insulinotropic and DPP-IV inhibitory activity following SGID, while GLP-1 secretion increased significantly (p < 0.01). SGID resulted in a significant increase in membrane potential, intracellular calcium and cyclic AMP concentration (p < 0.001) versus a glucose control, indicating that insulin secretion may be mediated by the KATP channel-dependent and the protein kinase A pathways. Additionally, acute (90–120 min) and persistent (4 h) glucose-lowering effects of the blue whiting hydrolysate were observed in normal healthy mice. These results demonstrate that the blue whiting protein hydrolysate had significant metabolic effects relevant to glucose control in vivo.

Targeted mitochondrial therapy using MitoQ shows equivalent renoprotection to angiotensin converting enzyme inhibition but no combined synergy in diabetes

Mitochondrial dysfunction is a pathological mediator of diabetic kidney disease (DKD). Our objective was to test the mitochondrially targeted agent, MitoQ, alone and in combination with first line therapy for DKD. Intervention therapies (i) vehicle (D); (ii) MitoQ (DMitoQ;0.6 mg/kg/day); (iii) Ramipril (DRam;3 mg/kg/day) or (iv) combination (DCoAd) were administered to male diabetic db/db mice for 12 weeks (n = 11–13/group). Non-diabetic (C) db/m mice were followed concurrently. No therapy altered glycaemic control or body weight. By the study end, both monotherapies improved renal function, decreasing glomerular hyperfiltration and albuminuria. All therapies prevented tubulointerstitial collagen deposition, but glomerular mesangial expansion was unaffected. Renal cortical concentrations of ATP, ADP, AMP, cAMP, creatinine phosphate and ATP:AMP ratio were increased by diabetes and mostly decreased with therapy. A higher creatine phosphate:ATP ratio in diabetic kidney cortices, suggested a decrease in ATP consumption. Diabetes elevated glucose 6-phosphate, fructose 6-phosphate and oxidised (NAD+ and NADP+) and reduced (NADH) nicotinamide dinucleotides, which therapy decreased generally. Diabetes increased mitochondrial oxygen consumption (OCR) at complex II-IV. MitoQ further increased OCR but decreased ATP, suggesting mitochondrial uncoupling as its mechanism of action. MitoQ showed renoprotection equivalent to ramipril but no synergistic benefits of combining these agents were shown.

Heptamethoxyflavone Reduces Phosphodiesterase Activity and T-Cell Growth in vitro

In a previous study, we reported that interleukin-4 production was reduced in spleen cells of mice administered 3,5,6,7,8,3′,4′-heptamethoxyflavone (HMF), which is a polymethoxyflavone found at high concentrations in the peel of various citrus fruits. In this study, we investigated the function of HMF on the growth of T cells cultured from the spleens of mice. HMF decreased the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) by anti-CD3/CD28 antibody-stimulated mouse spleen cells. HMF inhibited the activities of phosphodiesterase (PDE) enzymes prepared from bovine brain and human PDE_4B and PDE_3B enzymes. The cyclic AMP (cAMP) content in anti-CD3/CD28 antibody-stimulated spleen cells increased after HMF treatment in vitro. These results suggest that HMF inhibits T-cell growth and affects immune function via reduced PDE activity and increased cAMP content.

Gold nanoparticles/tetraaminophenyl porphyrin functionalized multiwalled carbon nanotubes nanocomposites modified glassy carbon electrode for the simultaneous determination of p-acetaminophen and p-aminophenol

A novel electrochemical platform was designed and prepared for simultaneous determination of p-acetaminophen (AMP) and p-aminophenol (AP) by combining the excellent conductivity and electrocatalytic activities of tetraaminophenyl porphyrin functionalized multi-walled carbon nanotubes (CNTs-CONH-TAPP) and gold nanoparticles (AuNPs). The as-synthesized CNTs-CONH-TAPP composites were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscope. The incisive oxidation current responses of AMP and AP at the modified electrode promised a sensitive and selective simultaneous determination of AMP and AP. Under optimized conditions, the peak currents were directly proportional to the concentrations of AMP and AP over the ranges of 4.5–500μmolL−1 and 0.08–60μmolL−1, respectively, and the limits of detection were 0.44μmolL−1 for AMP and 0.025μmolL−1 for AP(S/N=3) respectively. The proposed modified electrode showed excellent selectivity, reproducibility and long-term stability and could be applied in simultaneous determination of p-acetaminophen and p-aminophenol in real samples.

Thermal Degradation Rate of 2-Amino-2-methyl-1-propanol to Cyclic 4,4-Dimethyl-1,3-oxazolidin-2-one; Mechanistic Aspects and Kinetics Investigation

Using initial rate data, the mechanistic investigation for the thermal degradation kinetics of 2-amino-2-methyl-1-propanol (AMP) to 4,4-dimethyl-1,3-oxazolidin-2-one (DMOZD) as a function of amine and CO2 concentration in the solution was performed. Activation energies of different reaction steps in introduced mechanisms imply that the reaction between AMP and CO2 to produce carbamate will happen close to equilibrium conditions, while the carbamate will tends to revert back to initial amine rather than convert to the DMOZD at lower temperatures. Investigation of different forms of reaction pathways and various reaction orders for reactants including AMP and CO2 demonstrates that the actual reaction mechanism is complex. The closest and simplest mechanism to fit the experimental data provides noninteger reaction order with respect to AMP and CO2 concentration in the rate equation, which indicated more complexity of the reaction mechanism. Through the degradation rate data, the activation energy and reactio...

Creatine Monohydrate Enhances Energy Status and Reduces Glycolysis via Inhibition of AMPK Pathway in Pectoralis Major Muscle of Transport-Stressed Broilers.

Creatine monohydrate (CMH) contributes to reduce transport-induced muscle rapid glycolysis and improve meat quality of broilers, but the underlying mechanism is still unknown. Therefore, this study aimed to investigate the molecular mechanisms underlying the ameliorative effects of CMH on muscle glycolysis metabolism of transported broilers during summer. The results showed that 3 h transport during summer elevated chicken live weight loss and plasma corticosterone concentration; decreased muscle concentrations of ATP, creatine, and energy charge value; increased muscle AMP concentration and AMP/ATP ratio; and upregulated muscle mRNA expression of LKB1 and AMPKα2, as well as protein expression of p-LKB1Thr189 and p-AMPKαThr172, which subsequently resulted in rapid glycolysis in the pectoralis major muscle and consequent reduction of meat quality. Dietary addition of CMH at 1200 mg/kg ameliorated transport-induced rapid muscle glycolysis and reduction of meat quality via enhancement of the energy-buffering capacity of intramuscular phosphocreatine/creatine system and inhibition of AMPK pathway.

P14 LW-AFC treatment improves learning-memory ability and brain glucose metabolism in a mouse model of Alzheimer’s Disease

Objective: Alzheimer’s disease (AD) causes progressive hippocampus dysfunctions leading to the impairment of learning and memory ability and a reduced uptake rate of glucose in the hippocampus. LW-AFC is a new formula derived from the classical traditional Chinese medicinal prescription Liuwei Dihuang decoction. In this study, we investigated the beneficial and protective effects of LW-AFC in learning-memory ability and brain glucose metabolism in a widely used AD model, the senescence-accelerated prone mouse (SAMP8). Methods: SAMP8 mice were administrated LW-AFC (1.6 g/kg) for 2 months. The Morris water maze (MWM) test, shuttle box test, and novel object recognition test, were all used to evaluate cognition abilities. Fluorodeoxyglucose positron emission tomography (FDG-PET) was employed to detect the level of glucose uptake in the mouse brain. The concentrations of ATP, ADP and AMP were determined by HPLC. Results: The results from the MWM, shuttle box, and novel object recognition tests showed impairments in object recognition memory and spatial learning and memory, and active avoidance in SAMP8 mice. Administration of LW-AFC ameliorated the impairments in learning and memory abilities. The FDG-PET results showed a decrease in the uptake of glucose in the brains of SAMP8 mice with increasing age. LW-AFC enhanced glucose uptake in the brain of SAMP8 mice. Decreases in the concentrations of ATP, ADP and AMP were also found in the brains of SAMP8 mice. Administration of LW-AFC increased the concentration of all energy substances. Conclusion: LW-AFC could ameliorate deterioration of cognition in SAMP8 mice by improving glucose metabolism.

O34 Endothelium-independent vasorelaxant effect of Thymus linearis via inhibition of phosphodiesterases in porcine coronary artery

Thymus linearis Benth. indigenous to Pakistan has been traditionally used for the treatment of various diseases including hypertension. The aim of the study was to investigate the vasorelaxant effect of Thymus linearis in porcine coronary artery rings. Aqueous-methanolic extract and various fractions (butanol, ethyacetate and aqueous) of Thymus linearis were prepared. The effects of extract and fractions were assessed using coronary artery rings and various pharmacological tools were applied to characterize the underlying mechanism of active fraction (butanol). The inhibitory effect of butanolic fraction was also studied on phosphodiesterases using radio enzymatic assay. Phytochemical studies were also carried out using GCMS. The aqueous-methanolic extract of Thymus linearis elicited similar relaxations in coronary artery rings with and without endothelium in a dose-dependent manner. Among the fractions butanolic fraction of Thymus linearis (TLB) was found to be the most potent. TLB significantly potentiated the relaxation induced by forskolin, isoproterenol, sodium nitroprusside and atrial natriuretic peptide whereas the relaxation induced by YC-1, BAY 41-2272, levcromakalim and 1-EBIO was unaffected by TLB. Pretreatment with TLB inhibited the contraction induced by KCl, CaCl2 and U46619 in endothelium denuded coronary artery rings. Furthermore, TLB significantly inhibited the PDE activity (PDE1CaM activated PDE2, PDE3, PDE4 AND PDE5) in a concentration-dependent manner. GCMS analysis revealed the presence of thymol and Carvacrolas as major constituents. In conclusion, TLB induced endothelium-independent relaxations in porcine coronary artery rings by acting directly at the vascular smooth muscle to increase concentrations of both cyclic AMP and cyclic GMP via inhibition of various PDEs.

New insights on the regulation of the adenine nucleotide pool of erythrocytes in mouse models.

The observation that induced torpor in non-hibernating mammals could result from an increased AMP concentration in circulation led our investigation to reveal that the added AMP altered oxygen transport of erythrocytes. To further study the effect of AMP in regulation of erythrocyte function and systemic metabolism, we generated mouse models deficient in key erythrocyte enzymes in AMP metabolism. We have previously reported altered erythrocyte adenine nucleotide levels corresponding to altered oxygen saturation in mice deficient in both CD73 and AMPD3. Here we further investigate how these Ampd3-/-/Cd73-/- mice respond to the administered dose of AMP in comparison with the control models of single enzyme deficiency and wild type. We found that Ampd3-/-/Cd73-/- mice are more sensitive to AMP-induced hypometabolism than mice with a single enzyme deficiency, which are more sensitive than wild type. A dose-dependent rightward shift of erythrocyte p50 values in response to increasing amounts of extracellular AMP was observed. We provide further evidence for the direct uptake of AMP by erythrocytes that is insensitive to dipyridamole, a blocker for ENT1. The uptake of AMP by the erythrocytes remained linear at the highest concentration tested, 10mM. We also observed competitive inhibition of AMP uptake by ATP and ADP but not by the other nucleotides and metabolites tested. Importantly, our studies suggest that AMP uptake is associated with an erythrocyte ATP release that is partially sensitive to inhibition by TRO19622 and Ca++ ion. Taken together, our study suggests a novel mechanism by which erythrocytes recycle and maintain their adenine nucleotide pool through AMP uptake and ATP release.

Downregulation of iNOS and elevation of cAMP mediate the anti-inflammatory effect of glabridin in rats with ulcerative colitis.

Alternative medicine is widely accepted by public and becoming an attractive approach for treatment of various diseases. Glabridin (Gla), a major flavonoid present in licorice root, was reported to have antioxidant and anti-inflammatory properties. The study aimed to investigate the possible protective role of Gla against dextran sulphate sodium (DSS)-induced ulcerative colitis (UC) in rats and to clarify the molecular mechanisms underlying Gla function. Forty male Wistar rats were divided into control, colitis group (rats received 5% DSS in drinking water for 7days), Gla group (50mg/kg, orally, once daily), and sulfasalazine (SLZ) group (500mg/kg, orally, once daily). Each of Gla and SLZ was administered 1week ahead of DSS and parallel with its administration. Gla ameliorated the inflammatory alterations induced by DSS. Gla group showed a reduction in colon concentration of tumor necrosis factor-alpha (TNF-α) and a decreased colon myeloperoxidase activity (MPO). Gla treatment downregulated inducible nitric oxide synthase (iNOS) gene expression in rat colon with a decreased content of nitric oxide (NO). Gla also increased cyclic AMP (cAMP) concentration in rat colon compared to colitis group. Such findings were comparable to or even better than those obtained by SLZ treatment. The histological features of UC such as ulceration and inflammatory cell infiltrations were improved in rat group treated by Gla. Gla proved a potent anti-inflammatory role in UC through different mechanisms and, being a natural product, it could be safely used as a protective measure in inflammatory bowel diseases.