OBJECTIVETo test the different contrctile responses of extracellular nucleotides, such as ATP, UTP and nucleotide uridine adenosine tetraphosphate (Up4A) in gastric longitudinal muscle (LM) and circular muscle (CM). Examined the effect of P2X and P2Y receptor antagonists (in this study, we used IP5I and suramin) and cyclooxygenase inhibitor (indomethacin) on Up4A induced contractile responses in LM and CM.

METHODSThe rats were sacrificed and the stomachs were opened to gain LM and CM. Using organ bath system to assess contrctile responses of smooth muscle.

RESULTSUp4A could induce contractile responses in both CM and LM, which were similar with ATP and UTP. IP5 did not attenuate Up4A could induce contractions in both LM and CM, but suramin and indomethacin significantly inhibited Up4A contraction in CM, but not in LM.

CONCLUSIONOur results suggest that extracellular nucleosides and their inhibitors induce different responses between LM and CM.

Adenosine Triphosphate ; pharmacology ; Animals ; Dinucleoside Phosphates ; pharmacology ; Indomethacin ; Muscle Contraction ; Muscle, Smooth ; physiology ; Nucleotides ; pharmacology ; Rats ; Suramin ; Uridine Triphosphate ; pharmacology

OBJECTIVETo study the effects of nucleotides on apoptosis of thymocytes in mice.

METHODSApoptosis model in vivo was first established and 25 KM mice, 4 weeks old, were randomly divided into 5 groups. One group was control, and the others were test groups. Mice in test groups were injected with DEX (25 mg/kg) and the controls were treated with normal saline. 4, 8, 16, and 24 hours later the thymus and spleen were weighed and lymphocytes in thymus were separated. The apoptosis of lymphocytes was analyzed by using DNA electrophoresis and flow cytometry. 16 hours later lymphocytes apoptosis reached a peak and lasted 24 hours. Methods used to establish apoptosis model in vivo were: mice (4 weeks old) were injected with DEX (25 mg/kg), and thymus lymphocytes were separated 16 hours later and analyzed. The effects of nucleotides on apoptosis of mice thymocytes were investigated in experiment 2. Sixty KM mice, 20 g +/- 2g, 4 weeks old, were divided into four treatments: negative control group (NC), positive control group (PC), nucleotides-additive group 1 (NTS1) and nucleotides-additive group 2 (NTS2).

RESULTSBody weight gained in NST1 and NST2 were 3.71 g, 4.01 g respectively, significantly higher than NC (2.74 g) (P < 0.01) and in NST2 was significantly higher than in PC (2.96 g) (P < 0.01). Thymus index and spleen index were decreased significantly (P < 0.01), and no difference was found with the supplementation of nucleotides (P > 0.05). [Ca2+]i increased to 167.37 nmol/L, 191.16 nmol/L, 180.78 nmol/L in PC, NST1 and NST2 with DEX, being significantly higher than in NC (103.76 nmol/L) (P < 0.01). The percent of apoptosised thymocytes in groups were 0.31%, 11.93%, 9.82%, 11.15%, respectively. Thymus index and spleen index, cell apoptosis and [Ca2+]i were not differed significantly among PC, NTS1 and NTS2 groups.

CONCLUSIONNucleotides should have no significant effects on apoptosis of thymocytes in mice in vivo.

Animals ; Apoptosis ; drug effects ; Dexamethasone ; pharmacology ; Lymphocytes ; cytology ; Male ; Mice ; Nucleotides ; pharmacology ; Random Allocation ; Thymus Gland ; cytology

AIMIn order to evaluate the regulatory effects of nucleotides and adenosine on ATP-sensitive potassium channel (K(ATP)) in artery smooth muscles, the effects of them on vascular relaxation induced by K(ATP) opener pinacidil(Pin) were investigated.

METHODSThe isolated endothelium- denuded aorta rings were preincubated with nucleotides or nucleotides and glibenclamide (Gli) for 10 min, the vascular relaxation induced by Pin in aorta precontracted with 20 mmol x L(-1) KCl was observed.

RESULTSAfter the isolated endothelium-denuded aorta rings were preincubated with ATP, ADP, UDP, GTP and adenosine (Ade) 100 micromol x L(-1) respectively, the vascular relaxation induced by Pin was changed as following: (1) ATP could inhibit the K(ATP) activation by Pin and enhance the blockade of K(ATP) by Gli. (2) ADP could inhibit the K(ATP) activation by Pin and attenuate the blockade of K(ATP) by Gli. (3) The regulatory effect of Ade on K(ATP) was similar with that of ADP. (4) UDP could enhance the K(ATP) activation by Pin and attenuate the blockade of K(ATP) by Gli. (5) GTP could enhance the K(ATP) activation by Pin, but had no effects on the blockade of K(ATP) by Gli.

CONCLUSIONNucleotides and adenosine, related to energy metabolism, could modulate the functions of K(ATP) in vascular smooth muscle. But their pharmacological characteristics were different.

Animals ; Aorta ; cytology ; drug effects ; Glyburide ; pharmacology ; In Vitro Techniques ; KATP Channels ; metabolism ; Male ; Muscle, Smooth, Vascular ; drug effects ; Nucleotides ; pharmacology ; Pinacidil ; pharmacology ; Rats ; Rats, Wistar ; Vasodilator Agents ; pharmacology

OBJECTIVETo study the changes of neutral alpha-glucoside activity in the epididymis of heroin-dependent and heroin-withdrawal rats, and to investigate the effects of intervention with purine nucleotide (AMP and GMP).

METHODSEighty Wistar rats were randomly divided into 8 groups of equal number, control, nucleotide, heroin, heroin + nucleotide, 3 d withdrawal, 9 d withdrawal, 3 d nucleotide (nucleotide administrated for 3 days after heroin withdrawal) and 9 d nucleotide (nucleotide administrated for 9 days after heroin withdrawal). Neutral alpha-glucosidase activity in the epididymis was detected in each group of rats.

RESULTSCompared with the control group, neutral alpha-glucoside activity was markedly decreased in the heroin group (P < 0.05), and also in the 3 d and 9 d withdrawal groups, although with no significant differences (P > 0.05).

CONCLUSIONHeroin reduces neutral alpha-glucoside activity in the epididymis of rats, and this effect may continue for some time after drug withdrawal, while purine nucleotide can keep neutral alpha-glucosidase activity in a relatively stable state.

Animals ; Epididymis ; chemistry ; Heroin ; adverse effects ; Heroin Dependence ; metabolism ; Male ; Purine Nucleotides ; pharmacology ; Rats ; Rats, Wistar ; alpha-Glucosidases ; metabolism

To explore the mechanism of autophagic death of acute myelocytic leukemia cell U937 induced by clofarabine, the MTT bioassay was used to analyze the growth inhibitory effect and half inhibition concentration on U937 incubated in vitro with different concentrations of clofarabine for 24 and 48 hours, and the flow cytometry was used to detect the autophagy rate of U937. The expression of Beclin 1 in U937 treated by clofarabine for 48h was measured by Western blot. The results indicated that when U937 cells were treated with 0.01 µmol/L and 0.15 µmol/L clofarabine for 48 hours, the proliferation inhibition rate was 46.92% ± 4.24% and 86.10% ± 1.16%, and the half inhibition concentration of clofarabine was 0.022 µmol/L. With 0.01 µmol/L and 0.1 µmol/L clofarabine on U937 for 48 hours, the autophagy rate was 11.0033% ± 1.4387% and 59.4133% ± 3.5409%, and increased in dose-dependent manner (r = 0.99). Meanwhile the Beclin 1 was upregulated along with increase of clofarabine concentration, as compared with control group, the difference was statistically significant (P < 0.05). It is concluded that the different concentrations of clofarabine can significantly inhibit the proliferation of U937 in dose-dependent manner, and the mechanism of autophagic cell death in U937 may be associated with the upregulation of Beclin 1 expression.
Adenine Nucleotides ; pharmacology ; Apoptosis ; drug effects ; Apoptosis Regulatory Proteins ; metabolism ; Arabinonucleosides ; pharmacology ; Autophagy ; drug effects ; Beclin-1 ; Cell Proliferation ; drug effects ; Humans ; Membrane Proteins ; metabolism ; U937 Cells

Antiviral Agents ; pharmacology ; therapeutic use ; Drug Administration Schedule ; Hepatitis B Vaccines ; therapeutic use ; Hepatitis B, Chronic ; drug therapy ; therapy ; Humans ; Interferons ; therapeutic use ; Nucleotides ; pharmacology ; therapeutic use

OBJECTIVES: To study the effect of procalcitonin (PCT) on lipopolysaccharide (LPS)-induced expression of the pyroptosis-related proteins nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) and caspase-1 in human umbilical vein endothelial cells (HUVECs). METHODS: HUVECs were induced by LPS to establish a model of sepsis-induced inflammatory endothelial cell injury. The experiment was divided into two parts. In the first part, HUVECs were randomly divided into four groups: normal control, LPS (1 μg/mL), PCT (10 ng/mL), and LPS+PCT (n=3 each). In the second part, HUVECs were randomly grouped: normal control, LPS, and LPS+PCT of different concentrations (0.1, 1, 10, and 100 ng/mL) (n=3 each). Quantitative real-time PCR and Western blot were used to measure the mRNA and protein expression levels of NLRP3 and caspase-1 in each group. RESULTS: In the first experiment: compared with the normal control group, the PCT, LPS, and LPS+PCT groups had significantly upregulated mRNA and protein expression levels of NLRP3 and caspase-1 (P<0.05); compared with the LPS group, the LPS+PCT group had significantly downregulated mRNA and protein expression levels of NLRP3 and caspase-1 (P<0.05). In the second experiment: compared with those in the LPS group, the mRNA and protein expression levels of NLRP3 and caspase-1 in the LPS+PCT of different concentrations groups were significantly downregulated in a concentration-dependent manner (P<0.05). CONCLUSIONS LPS can promote the expression of the pyroptosis-related proteins NLRP3 and caspase-1 in HUVECs, while PCT can inhibit the LPS-induced expression of the pyroptosis-related proteins NLRP3 and caspase-1 in HUVECs in a concentration-dependent manner.
Humans ; Caspase 1/metabolism* ; Human Umbilical Vein Endothelial Cells/metabolism* ; Lipopolysaccharides/pharmacology* ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Procalcitonin ; Nucleotides/pharmacology*

C-Terminal carboxyl methylation of a human placental 23 kDa protein catalyzed by membrane-associated methyltransferase has been investigated. The 23 kDa protein substrate methylated was partially purified by DEAE-Sephacel, hydroxyapatite and Sephadex G-100 gel filtration chromatographies. The substrate protein was eluted on Sephadex G-100 gel filtration chromatography as a protein of about 29 kDa. In the absence of Mg2+, the methylation was stimulated by guanine nucleotides (GTP, GDP and GTPgammaS), but in the presence of Mg2+, only GTPgammaS stimulated the methylation which was similar to the effect on the G25K/rhoGDI complex. AFC, an inhibitor of C-terminal carboxyl methylation, inhibited the methylation of human placental 23 kDa protein. These results suggests that the substrate is a small G protein different from the G25K and is methylated on C-terminal isoprenylated cysteine residue. This was also confirmed by vapor phase analysis. The methylated substrate protein was redistributed to membrane after in vitro methylation, suggesting that the methylation of this protein is important for the redistribution of the 23 kDa small G protein for its putative role in intracellular signaling.
Cysteine/metabolism* ; Female ; GTP-Binding Proteins/metabolism* ; Guanine Nucleotides/pharmacology ; Human ; Methylation ; Placenta/metabolism* ; Placenta/enzymology ; Pregnancy ; Pregnancy Proteins/metabolism* ; Protein Methyltransferases/metabolism*

Metallothionein-3 (MT-3), renamed as growth inhibitory factor (GIF), is a brain specific member of the metallothionein family. Human dUTPase is a recently found protein in brain that can interact with hMT-3. They have the growth inhibitory activity on neuron cell by interaction. To study the affection of hMT-3 to dUTPase's eliminating the cellular toxicity caused by dUTP, the pSVHA-dUTPase and pFLag-hMT-3 genes have been transfected into HEK293 cells. In addition, the dUTPase and hMT-3 proteins were expressed in BL21 to study the role of hMT-3 on the hydrolyzation of dUTP by dUTPase. The results demonstrate that the cells co-transfected with dUTPase and hMT-3 genes have more strong resistibility to dUTP than the cells transfected only with dUTPase gene. And that the hMT-3 protein can accelerate the hydrolyzation of dUTP by dUTPase. All these indicate that hMT-3 can cooperate with dUTPase to protect better the 293 cells from dUTP. This research offered the theoretic elements for the application of hMT-3 and dUTPase in chemic cure.
Cell Line ; Deoxyuracil Nucleotides ; antagonists & inhibitors ; chemistry ; Nerve Tissue Proteins ; chemistry ; genetics ; pharmacology ; Neurons ; cytology ; drug effects ; Protein Interaction Domains and Motifs ; Pyrophosphatases ; chemistry ; genetics ; pharmacology ; Recombinant Proteins ; biosynthesis ; genetics ; pharmacology ; Transfection

Adult ; Aged ; Antiviral Agents ; pharmacology ; DNA-Directed DNA Polymerase ; genetics ; Drug Resistance, Viral ; genetics ; Female ; Genes, Viral ; Hepatitis B virus ; drug effects ; genetics ; Humans ; Lamivudine ; pharmacology ; Male ; Middle Aged ; Nucleotides ; pharmacology ; Young Adult