PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “ATP (adenosine triphosphate)”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2007

Enzyme-based field-effect transistor for adenosine triphosphate (ATP) sensing.

Adenosine triphosphate (ATP) not only functions as an energy-carrier substance and an informative molecule, but also acts as a marker substance in studies of both bio-traces and cellular/tissular viability. Due to the importance of the ATP function for living organisms, in situ assays of ATP are in demand in various fields, e.g., hygiene. In the present study, we developed an ATP sensor that combines the selective catalytic activity of enzyme and the properties of an ion selective field effect transistor (ISFET). In this system, the ATP hydrolyrase, "apyrase (EC 3.6.1.5.)" is encased in a gel and mounted on a Ta(2)O(5) ISFET gate surface. When the enzyme layer selectively catalyzes the dephosphorylation of ATP, protons are accumulated at the gate because the enzymatic reaction produces H(+) as a byproduct. Based on the interfacial enzymatic reaction, the response from the ISFET is completely dependent upon the ATP concentration in the bulk solution. This device is readily applicable to practical in situ ATP measurement, e.g. hygienic usage.

Adenosine Triphosphate↗
PubMed2001

Differential regulations between adenosine triphosphate (ATP)- and uridine triphosphate-induced Cl(-) secretion in bovine tracheal epithelium. Direct stimulation of P1-like receptor by ATP.

Adenosine 5'-triphosphate (ATP) stimulates airway epithelial Cl(-) secretion in a complicated manner. We examined the difference between ATP- and uridine 5'-triphosphate (UTP)-induced responses of short-circuit current (Isc) in bovine tracheal epithelium treated with amiloride. Each nucleotide caused an increase in Isc composed of the first and second peaks, where the second peak induced by ATP was higher compared with UTP. The ATP-induced second peak was inhibited by the protein kinase (PK) A inhibitor H89, saturation of P1 receptor with adenosine, and the P1 receptor antagonist 8-p-sulfophenyltheophylline, but not by the Ca(2+) chelator ethyleneglycol-bis-(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid plus the endoplasmic reticulum Ca(2+)-pump inhibitor thapsigargin, the adenosine breakdown enzyme adenosine deaminase, the ectonucleotidase inhibitor alpha,beta-methyleneadenosine 5'-diphosphate, or saturation of P2Y2 receptor with UTP. Thus, the response is associated with PKA-dependent pathway via P1-like receptor but not with Ca(2+)-dependent pathway via P2Y2 receptor, and ATP degradation products do not contribute to this response. Further, stimulation of cells with ATP increased PKA activity. In addition, pretreatment with glybenclamide, an inhibitor of cystic fibrosis transmembrane conductance regulator, reduced the second peak of Isc induced by ATP but was without effect on that induced by UTP. Therefore, ATP stimulates glybenclamide-sensitive Cl(-) secretion, and this action is partly mediated by PKA-dependent pathway via P1-like receptor.

Adenosine↗
PubMedDate not supplied

Adenosine triphosphate (ATP) in human spermatozoa.

The seminal adenosine triphosphate (ATP) content was determined by bioluminescence after treatment with trichloroacetic acid (TCA) in 81 semen samples 1.5 h after ejaculation obtained from men attending our fertility clinic, and selected to contain either 20% or less spermatozoa with good progressive motility (n = 22), or 60% or more spermatozoa with good progressive motility (n = 59) (Study I), and in 18 semen samples from fertile men 30 min and 3.5 h after ejaculation (Study II). The latter samples were divided into 2 equally large groups according to sperm motility. In Study I the mean sperm ATP concentration was significantly higher in the semen samples with bad motility (0.63 nmol per living spermatozoa x 10(-6)) than in semen samples with good motility (0.39 nmol per living spermatozoa x 10(-6); P less than 0.01). In Study II the ATP concentration per living spermatozoa was also lower in the group with the best motility in comparison with the spermatozoa with lower motility (P less than 0.01), both 30 min and 3.5 h after ejaculation. During the 3-5 h incubation the sperm ATP concentration decreased by 21% (P less than 0.01) in the former group of samples but remained unchanged in the latter group. The results indicate that, in semen samples with highly motile spermatozoa, the consumption of ATP is higher than in semen samples with impaired sperm motility. It is therefore essential that the time between ejaculation and ATP measurement is as short as possible to obtain comparable results. Repeated ATP measurements in combination with an analysis of the number of living spermatozoa, may provide further information on the fertilizing capacity of spermatozoa.

Adenosine Triphosphate↗
PubMed1982

Adenosine triphosphate (ATP) hydrolysis promoted by cobalt (III). Participation of polynuclear metal complexes.

Complex formation between ATP (adenosine 5'-triphosphate) and tn2COIII(aq) (tn = trimethylenediamine) and resulting hydrolysis of the ATP to ADP (adenosine 5'-diphosphate), AMP (adenosine 5'-monophosphate), PPi (pyrophosphate), and Pi (orthophosphate) have been examined by means of 31P nmr. With ATP approximately 0.1 M and tn2CoIII-(aq) up to 0.3 M, complex formation was promoted by equilibrating solutions for a period at pH 4, after which hydrolysis was allowed to proceed at each of several pHs in the range 5 to 9 prior to quenching by addition of strong base. With ATP 0.01 M and tn2CoIII(aq) up to 0.08 M, the above procedure was followed in some cases; in other experiments the pH of each ATP/tn2CoIII(aq) solution was adjusted immediately to a value in the range 5 to 9 with the remainder of the procedure as before. In most cases the hydrolysis was at 25 degrees C, but temperature dependence was also examined. The integrals for the beta-phosphorus resonance have been used to analyze for ATP in the quenched solutions; independent measurements of ATP by an enzyme/spectrophotometric method (Bergmeyer) gave similar results. Cobalt to ATP molar ratios up to 1 produce tn2CoIII-ATP as the predominant ATP complex; this 1:1 complex shows no detectable acceleration in hydrolysis compared to free ATP. Cobalt to ATP molar ratios of greater than 1 lead to complexes of type (tn2CoIII)2ATP and (tn2CoIII)3ATP, which exhibit greatly enhanced reactivity towards ATP hydrolysis. At a 2:1 molar ratio (0.1 or 0.01 M ATP), the enhancement in rate is approximately 10(5) at pH 7 where the rate is a maximum (comparison for 25 degrees C); at higher molar ratios the rate enhancements are even greater. The results support the view that effective metal ion catalysis of ATP hydrolysis requires formation of reactive species involving more than one metal ion per ATP.

Adenosine Triphosphate↗
PubMed1997

Halothane attenuates endothelium-dependent pulmonary vasorelaxant response to lemakalim, an adenosine triphosphate (ATP)-sensitive potassium channel agonist.

BACKGROUND: Lemakalim, an adenosine triphosphate (ATP)-sensitive potassium (K+(ATP)) channel agonist, causes profound pulmonary vasodilation in conscious dogs, which is attenuated during halothane anesthesia. The goal of the present study was to investigate the mechanism responsible for this attenuating effect of halothane. METHODS: Isolated canine pulmonary arterial rings were suspended for isometric tension recording in 25 ml organ baths. Rings with and without endothelium were contracted to 50% of their maximal response to phenylephrine, followed by the cumulative administration of lemakalim with or without exposure to halothane (0.5-1.5 minimum alveolar concentration [MAC] in dogs). Lemakalim dose-response curves were also generated in rings pretreated with the nitric oxide synthase inhibitor, Nw-nitro-L-arginine methyl ester (L-NAME); the cyclooxygenase inhibitor, indomethacin; or the K+(ATP) channel antagonist, glybenclamide. RESULTS: Compared with intact rings, the pulmonary vasorelaxant response to lemakalim was attenuated (P < 0.05) in endothelium-denuded rings. Halothane at 0.5 MAC had no effect on the vasorelaxant response to lemakalim. Halothane at 1 MAC attenuated (P < 0.05) the vasorelaxant response to lemakalim in intact rings, but not in endothelium-denuded rings. Halothane at 1.5 MAC attenuated (P < 0.05) the vasorelaxant response to lemakalim in both intact and endothelium-denuded rings. In endothelium-intact rings, indomethacin attenuated (P < 0.05) the vasorelaxant response to lemakalim, whereas L-NAME had no effect. Further, indomethacin, but not L-NAME, abolished the endothelium-dependent, halothane-induced attenuation of the lemakalim vasorelaxation response. Glybenclamide markedly attenuated (P < 0.05) lemakalim vasorelaxation at lemakalim doses less than 10(-6) M. CONCLUSIONS: Lemakalim-induced pulmonary vasorelaxation involves an endothelium-dependent and vascular smooth muscle component. Further, halothane attenuates the endothelium-dependent pulmonary vasorelaxant response to lemakalim via an inhibitory effect on vasodilator metabolites of the cyclooxygenase pathway.

Adenosine Triphosphate↗
PubMed1987

Permeability of red-cell membrane to adenosine triphosphate (ATP) molecules during hemorrhagic shock.

The findings of decreased adenosine triphosphate (ATP) levels in liver, kidney, and other tissues of animals in hemorrhagic shock were the rationale for previous experimental attempts to improve cell function by administration of fluids that contained high concentrations of ATP. The beneficial effects of this resuscitation, which are still controversial, were attributed to cellular uptake of ATP--it was assumed that cell membranes are permeable to this substrate. The effect of a high concentration of ATP in extracellular medium on intracellular ATP content was studied by using red blood cells (RBCs) from rabbits in control (normal) and in hemorrhagic shock states. The glucose-depleted RBCs were incubated in medium with 5 mMol/L ATP, and their ATP concentration fell markedly to the same level as seen in glucose-depleted RBCs incubated without ATP. The decrease of ATP in glucose-repleted RBCs, incubated with or without ATP, also did not show any significant difference. Similar to parallel experiments that used normal RBCs, the high extracellular ATP content did not substantially affect the intracellular ATP concentration in RBCs from animals in shock. This study indicates that ATP molecules in extracellular medium cannot penetrate either the normal RBC membrane or the RBC membrane during shock.

Adenosine Triphosphate↗
PubMed2004

Role of macula densa adenosine triphosphate (ATP) in tubuloglomerular feedback.

BACKGROUND: Recent studies have shown that adenosine triphosphate (ATP) is liberated from macula densa cells in response to increased tubular NaCl in vitro. We tested the hypothesis that increased NaCl in the macula densa stimulates the release of ATP, resulting in extracellular formation of adenosine which is involved in signal transmission of the tubuloglomerular feedback response. METHODS: Rabbit afferent arterioles and attached macula densas were simultaneously microperfused in vitro. Tubuloglomerular feedback was induced by increasing macula densa Na/Cl from 11/10 to 81/80 mmol/L and was measured before and after treatment. RESULTS: We first tested whether hydrolysis of ATP is required for tubuloglomerular feedback. When we enhanced conversion of ATP to adenosine by adding hexokinase or apyrase to the bath and arteriole lumen, the tubuloglomerular feedback response was augmented. During the control period, tubuloglomerular feedback decreased arteriole diameter by 2.2 +/- 0.2 microm. In the presence of hexokinase, tubuloglomerular feedback decreased diameter by 3.4 +/- 0.3 microm (N= 8) (P < 0.05, with vs. without hexokinase). In the apyrase group, tubuloglomerular feedback decreased diameter by 2.7 +/- 0.4 microm during the control period. When apyrase was added, tubuloglomerular feedback decreased diameter by 4.7 +/- 0.4 microm (N= 8) (P < 0.05, with vs. without apyrase). When hydrolysis of adenosine monophosphate (AMP) to adenosine was blocked by supplementing the bath with 100 micromol/L alpha,beta-methylene adenosine 5'-diphosphate (MADP), an inhibitor of 5'-nucleotidase, tubuloglomerular feedback response was blocked and diameter remained unchanged. We next studied whether ATP released from the macula densa binds to P(2) receptors and activates the tubuloglomerular feedback response. The P(2) purinergic receptor inhibitor suramin was added to both arteriole lumen and bath. During the control period, tubuloglomerular feedback decreased diameter by 3.7 +/- 0.5 microm. Suramin (100 micromol/L) did not significantly inhibit tubuloglomerular feedback, since in the presence of suramin diameter decreased by 3.8 +/- 0.3 microm (N= 7). Finally, we added the adenosine A(1) receptor inhibitor FK838 to both bath and lumen and found that it completely blocked high NaCl-induced tubuloglomerular feedback. CONCLUSION: We concluded that ATP released from the macula densa is broken down to form AMP in the extracellular space. AMP in turn is degraded by ecto-5'-nucleotidases to adenosine, which mediates signal transmission of the tubuloglomerular feedback response.

5'-Nucleotidase↗
PubMedDate not supplied

Adenosine triphosphate (ATP) concentrations and ATP/adenosine diphosphate ratios in human sperm of normospermic, oligospermic, and asthenospermic specimens and in their swim-up fractions: lack of correlation between ATP parameters and sperm creatine kinase concentrations.

The authors had previously found an inverse correlation between per sperm creatine phosphokinase activity and sperm concentrations in men. Because creatine phosphokinase is a key enzyme in sperm energy transport, the possible relationship of sperm creatine phosphokinase activity, sperm adenosine triphosphate (ATP) concentrations, sperm ATP/ADP (adenosine diphosphate) ratios, and computer-aided semen analysis sperm motility parameters were then studied. The ATP concentrations and ATP/ADP ratios, measured by high-pressure liquid chromatography in washed sperm, were similar in normospermic and oligospermic specimens (ATP: 123.1 +/- 21.6 vs. 90.0 +/- 24.5 pmol/10(6) sperm; ATP/ADP: 2.8 +/- 0.4 vs. 2.1 +/- 0.4, N = 32 and 17, mean +/- SEM), and in samples with normal and less than 40% sperm motility (ATP: 96.8 +/- 27.2 vs. 122.2 +/- 19.6 pmol/10(6) sperm; ATP/ADP: 2.4 +/- 0.5 vs. 2.8 +/- 0.4, n = 26 and 23). In the swim-up sperm fractions, which showed improved motility, the ATP concentrations, but not the ATP/ADP ratios, were lower than in the initial semen samples (ATP: 152.9 +/- 28.4 vs. 90.3 +/- 10.6 pmol/10(6) sperm, P less than 0.05; ATP/ADP: 3.3 +/- 0.5 vs. 3.9 +/- 0.7, N = 18 pairs of samples). This is consistent with our previous finding of a lower cytoplasmic content in sperm in swim-up fractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed1984

[Erythrocyte deformability and adenosine triphosphate (ATP) levels in normal pregnancy and puerperium].

Erythrocyte deformability and erythrocyte adenosine triphosphate (ATP) levels were measured in normal pregnancy and puerperium. Erythrocyte deformability was determined by measuring filtered volumes of red cell-plasma or buffer suspension per second. Erythrocytes from pregnant women at 16-27 weeks, 28-31 weeks and 36-41 weeks of gestation were found to be significantly less deformable than erythrocytes from non pregnant women. On 0-1 day after delivery, erythrocyte deformability was significantly reduced, compared with that at 36-41 weeks of gestation. Erythrocyte ATP levels at 16-27 weeks, 28-31 weeks and 36-41 weeks of gestation were significantly lower than that in non pregnant women. In puerperium, erythrocyte ATP levels dropped significantly compared with those in late gestational period. From these results, it was suggested that the depressed erythrocyte deformabilities were accompanied by a lowering of erythrocyte ATP levels in pregnancy and puerperium.

Adenosine Triphosphate↗
PubMedDate not supplied

The diagnostic value of seminal adenosine triphosphate (ATP) in an in vitro fertilization (IVF) program.

The level of adenosine triphosphate (ATP) was quantitated in semen samples used for in vitro fertilization of human oocytes. Seminal ATP level correlated with the concentration and percentage motility of spermatozoa but not with the in vitro fertilization rate of human oocytes. Seminal ATP measurement appears to have little diagnostic value in predicting the fertilizing capacity of spermatozoa as evaluated by the multivariate stepwise discriminant analysis.

Adenosine Triphosphate↗
PubMed1984

Metabolic intervention to affect myocardial recovery following ischemia.

Myocardial recovery during reperfusion following ischemia is critical to patient survival in a broad spectrum of clinical settings. Myocardial functional recovery following ischemia correlates well with recovery of myocardial adenosine triphosphate (ATP). Adenosine triphosphate recovery is uniformly incomplete during reperfusion following moderate ischemic injury and is therefore subject to manipulation by metabolic intervention. By definition ATP recovery is limited either by (1) energy availability and application in the phosphorylation of adenosine monophosphate (AMP) to ATP or (2) availability of AMP for this conversion. Experimental data suggest that substrate energy and the mechanisms required for its application in the creation of high energy phosphate bonds (AMP conversion to ATP) are more than adequate during reperfusion following moderate ischemic injury. Adenosine monophosphate availability, however, is inadequate following ischemia due to loss of diffusable adenine nucleotide purine metabolites. These purine precursors are necessary to fuel adenine nucleotide salvage pathways. Metabolic interventions that enhance AMP recovery rather than those that improve substrate energy availability during reperfusion are therefore recommended. The mechanisms of various metabolic interventions are discussed in this framework along with the rationale for or against their clinical application.

Adenine↗
PubMed1991

Adenosine triphosphate (ATP) and other nucleotides stimulate the hydrolysis of phosphatidylethanolamine in intact fibroblasts.

Addition of adenosine triphosphate (ATP) to [14C]ethanolamine-prelabeled NIH 3T3 fibroblasts resulted in rapid formation of [14C]ethanolamine from the prelabeled cellular phosphatidylethanolamine (PtdEtn) pool. After 2-min exposure, 10 microM ATP had near maximal effects on PtdEtn hydrolysis. Several other nucleotides, including UTP, ITP, and the stable ATP analog adenosine 5'-O-(3-thiotriphosphate) (ATP gamma S), also had stimulatory effects on PtdEtn hydrolysis with a potency comparable to that observed with ATP. The same nucleotides which acted on PtdEtn hydrolysis also had similar stimulatory effects on the hydrolysis of phosphatidylcholine (PtdCho) in [14C]choline-labeled cells. In isolated membranes, Mg2+ greatly enhanced the stimulatory effects of ATP and ATP gamma S, but not of other nucleotides, on the hydrolysis of PtdEtn and PtdCho. Results indicate that in isolated membranes, both ATP and ATP gamma S stimulate phospholipid hydrolysis by two different mechanisms, but in intact cells only one of these mechanisms appears to be responsive to externally added nucleotides.

Adenosine Diphosphate↗
PubMed1992

The effect of hypothermia on liver adenosine triphosphate (ATP) recovery following combined shock and ischemia.

During both hemorrhagic shock and ischemia, adenosine triphosphate (ATP) concentrations fall in liver tissue. Incomplete recovery of ATP correlates with cell death and subsequent organ dysfunction. Changes in liver ATP levels were evaluated in paired groups of rats subjected to combined hemorrhagic shock and ischemia. A second set of paired animals was studied over time with shock alone. One animal in each pair was maintained at 28 degrees C and the other at 37 degrees C. Ischemia was produced by occluding inflow to the left half of the liver, and tissue was obtained from this area in all animals studied. Adenosine triphosphate levels fell in warm and cold animals subjected to both shock and 60 minutes of ischemia but recovered more completely during reperfusion in the cold animals. Shock alone caused a steady fall in ATP levels in the warm, but not the cold rats. These biochemical changes may indicate a beneficial effect of moderate hypothermia in the management of severe liver hemorrhage requiring temporary occlusion of blood flow.

Adenosine Triphosphate↗
PubMed1993

Selective killing of murine leukemic cells by adenosine triphosphate (ATP): a study of the value of autologous bone marrow transplantation.

To assess the value of adenosine triphosphate (ATP) for ex vivo purging of leukemic cells in autologous bone marrow transplantation, its biological effects on the murine leukemic cell lines (WEHI3B and L1210) and normal murine bone marrow hemopoietic stem cells (CFU-C and CFU-S) were studied. After treatment with 4 mM of ATP for 6 h, the number of viable WEHI3B cells decreased to less than 0.1% of that of the control. Furthermore, 3H-thymidine incorporations were also completely inhibited in both WEHI3B cells and L1210 cells. These phenomena were related to the concentration and exposure period of ATP. Treatment of bone marrow mononuclear cells with ATP under the same condition reduced the number of CFU-C, day 9 CFU-S and day 12 CFU-S to only 58.5 +/- 8.7%, 92.6 +/- 8.2% and 83.5 +/- 28.5%, respectively, with no change in the number of marrow nucleated cells. Although the effect of ATP is not entirely specific to leukemic cells, these findings provide evidence that ATP is useful for purging residual tumor cells in autologous bone marrow transplantation.

Adenosine Triphosphate↗