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At least 343 records · Page 19Linked to original sources
PubMed1968

The release of adenosine triphosphate from frog skeletal muscle in vitro.

1. Active frog sartorius muscle in vitro liberates a substance into the bathing solution which has a pronounced stimulatory action on the frog heart.2. The stimulatory effect is not due to an increase in the K(+) concentration of the bathing solution, nor is it due to the liberation of catecholamines.3. In a molecular sieve chromatography procedure the stimulatory substance can be eluted in a single fraction which shows a maximum absorption of U.V. light at a wave-length of 265 nm, indicative of the presence of substances containing a purine ring.4. Low concentrations (10(-7)-10(-8) g/ml.) of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and uridine triphosphate (UTP) have a marked stimulatory action on the frog heart. The action of ATP and ADP on the heart is qualitatively very similar to that of the muscle bathing solution, while the action of UTP is distinctly different. The triphosphates of inosine, cytidine and guanosine stimulate the heart when in high concentration only. Adenosine and adenosine monophosphate do not stimulate the heart.5. Incubation of the muscle bathing solution and of solutions of ATP with the enzyme apyrase for the same time produces a similar marked reduction in the stimulatory action of both on the heart. Apyrase catalyses the break-down of nucleotide triphosphates to monophosphates.6. The elution behaviour of the stimulatory substance determined by molecular sieve chromatography is the same as that for ATP.7. The muscle bathing solution causes light to be emitted from firefly lantern extract, the pattern of light emission being similar to that produced by nucleotide triphosphates.8. The concentrations of ATP having the same quantitative action on the frog heart and on firefly extract as a given muscle bathing solution are almost identical, whereas the matching concentrations of ADP and UTP in the two methods of assay are widely different.9. It is concluded that ATP is released from active frog skeletal muscle in vitro. This release may play an important part in the reactive hyperaemia of muscular exercise since ATP has a powerful vasodilator action.

Adenosine Triphosphate↗
PubMed1980

The effect of exogenous adenosine triphosphate on potassium movements in HeLa cells.

The effect of exogenous adenosine triphosphate (ATP) on the potassium movements of cultured HeLa cells has been studied. The results obtained were consistent with the hypothesis that, in these cells, externally applied ATP activates a tightly coupled potassium-potassium (K-K) exchange mechanism. The response to ATP was characterized by a transient, 20-fold increase in both the potassium influx and potassium efflux. The tight coupling of the K-K exchange mechanism was confirmed by the results of several different types of experiment, all of which demonstrated the consistent matching of the ATP-stimulated fluxes. Two different strains of HeLa cells gave quantitatively different responses under similar experimental conditions. The reason for this difference was investigated and evidence was obtained which was consistent with the view that the membrane potential also influenced the HeLa cell K-K exchange mechanism.

Adenosine Triphosphate↗
PubMed1992

Glycine cytoprotection during lethal hepatocellular injury from adenosine triphosphate depletion.

Glycine protects renal tubule cells from cell death during adenosine triphosphate (ATP) depletion. Although the liver plays a key role in glycine metabolism, information is lacking regarding the effects of glycine on lethal hepatocellular injury. Thus, the aim of this study was to determine the potential cytoprotective role of glycine during ATP depletion of rat hepatocytes. Metabolic inhibition with 2.5 mmol/L potassium cyanide (KCN) was used to produce ATP depletion. Hepatocyte suspensions treated with KCN had a 2-hour viability of 5.9% +/- 2.0%, whereas cells treated with KCN in the presence of 2.0 mmol/L glycine had a viability of 80.2% +/- 1.5%, which was virtually identical to controls (81.5% +/- 1.9%). Glycine cytoprotection was dose dependent and amino acid specific. The cytoprotective effect of glycine was not mediated by protein synthesis, glycine mitochondrial metabolism, cytosolic acidosis, or preservation of either intracellular cellular glutathione or ATP. However, glycine did decrease total cellular proteolysis by 18% +/- 2%, 25% +/- 3%, and 33% +/- 1% after 1, 2, and 3 hours of KCN treatment, respectively (P less than 0.01). Inhibition of proteolysis by glycine was dose dependent over the same range as its cytoprotection. The results suggest that glycine protects against hepatocellular injury by inhibiting degradative proteolytic activity. It was concluded that proteolysis may be an important mechanism contributing to lethal injury of hepatocytes during ATP depletion.

Adenosine Triphosphate↗
PubMed2003

Distinct intracellular Ca2+ response to extracellular adenosine triphosphate in pancreatic beta-cells in rats and mice.

Extracellular adenosine triphosphate (ATP) has distinct effects on insulin secretion from pancreatic beta-cells between rats and mice. Using a confocal microscope, we compared changes between rats and mice in cytosolic free calcium concentration ([Ca2+]c) in pancreatic beta-cells stimulated by extracellular ATP. Extracellular ATP (50 microM) induced calcium release from intracellular calcium stores by activating P2Y receptors in both rat and mouse beta-cells. The intracellular calcium release stimulated by extracellular ATP is significantly smaller in amplitude and longer in duration in rat beta-cells than in mouse. In response to extracellular ATP, rat beta-cells activate store-operated calcium entry following intracellular calcium release. This response is lacking in mouse beta-cells. Rat and mouse beta-cells both responded to 9 mM glucose by increasing [Ca2+]c. This increase, however, was pronounced only in the rat beta-cells. In 9 mM glucose, extracellular ATP induced a pronounced calcium release above the increased level of [Ca2+]c in rat beta-cells. In mouse beta-cells, however, extracellular ATP did not exhibit calcium release on top of the increased level of [Ca2+]c in 9 mM glucose. These results demonstrate distinct responses between rat and mouse beta-cells to extracellular ATP under the condition of low and high glucose. Considering that extracellular ATP inhibits insulin secretion from mouse beta-cells but stimulates insulin secretion from rat beta-cells, we suggest that store-operated Ca2+ entry may be related to exocytosis in pancreatic rat beta-cells.

Adenosine Triphosphate↗
PubMed1994

beta-Hydroxybutyrate decreases adenosine triphosphate degradation products in human subjects.

Many disease states decrease intracellular adenosine triphosphate (ATP) levels and elevate body fluid purine levels. The use of specific metabolic substrates may reverse this process. This study was designed to test the hypothesis that beta-hydroxybutyrate, a substrate for ATP synthesis, decreases body fluid purine levels during interventions that induce ATP degradation. Decreases in these purine levels are metabolic markers for diminished ATP degradation. Two human models for stimulating ATP degradation were used to test the hypothesis. Rapid fructose infusion causes acute degradation of hepatic ATP, and ischemic exercise stimulates ATP consumption in skeletal muscle. The activity of beta-hydroxybutyrate was used in combination with phosphate, another important substrate for ATP synthesis. The studies were performed during a low-phosphate state in 10 normal subjects and during a high-phosphate state in 7 normal subjects. Metabolic variables, such as serum or urinary phosphate level, blood beta-hydroxybutyrate level, blood acetoacetate level, plasma or urinary purine level, blood lactate level, and blood ammonia level, were monitored during the study. After ischemic exercise of the forearm muscle, beta-hydroxybutyrate decreased the level of plasma total purines, blood lactate, and blood ammonia during the low-phosphate state but not during the high-phosphate state. During fructose-induced hepatic ATP breakdown, beta-hydroxybutyrate decreased late phase plasma purine increases under low-phosphate conditions only and decreased urinary total and radiolabeled purine elevations under both phosphate conditions. These data indicate that the infusion of beta-hydroxybutyrate may alter the balance from ATP degradation toward ATP resynthesis in muscle and liver by providing an immediate source of fuel and reducing equivalents under under specific metabolic conditions. This activity in combination with other metabolic interventions may have therapeutic value by restoring ATP pools in ATP-depleted tissues.

3-Hydroxybutyric Acid↗
PubMed1999

Evaluation of the internal thoracic arterial graft patency by the transthoracic Doppler method under continuous intravenous infusion of adenosine triphosphate disodium.

Usefulness of the Doppler method under continuous infusion of adenosine triphosphate disodium (ATP) for improvement of accuracy in the diagnosis of the left internal thoracic arterial graft (LITA) patency was examined using transthoracic ultrasonic echocardiography. 1) Influence of ATP on the Doppler velocity in a graft was examined in 7 patients with good LITA grafts using physiological saline as the control. In the ATP group, 80 mg of ATP was dissolved in 20 ml physiological saline and continuously infused at 0.14 mg/kg/min. In the saline group, an equal volume of physiological saline was administered and the blood flow velocity in the LITA was recorded continuously by the transthoracic Doppler method from the supraclavicular fossa approach. Results; ATP administration increased the blood flow velocity in the LITA and the rate of increase was 48.3% for systolic peak velocity, 111% for diastolic peak velocity, 64.4% for systolic time velocity integral and 99% for diastolic time velocity integral indicating particularly high rates of increase in diastolic components. The diastolic/systolic peak velocity ratio or diastolic fraction did not increase significantly. In the saline group, none of the parameters showed a change. 2) Angiographic findings of the LITA were compared with the measurement values of the diastolic components by the Doppler method to examine usefulness of diastolic component measurement with ATP infusion for diagnosis of LITA patency. Subjects were 19 patients with good LITA (group A) and 8 patients with bad LITA (group B). Results; while there were significant differences in the mean baseline diastolic peak velocity, mean diastolic time velocity integral and mean diastolic fraction between the groups, overlapping was seen in individual cases. However, the inter-group differences were more distinct by ATP infusion and the borderline values were 30 cm/sec for diastolic peak velocity and 10 for diastolic time velocity integral. 3) Reliability of the diagnosis for LITA patency by measuring the diastolic components using the Doppler method with ATP infusion was examined and compared with the angiographic findings as the gold standard. Subjects were 27 patients and the diagnostic criteria for good LITA were set at 30 cm/sec for diastolic peak velocity and 10 for diastolic time velocity integral. Results; sensitivity and specificity of the Doppler method with ATP infusion were 100% for diagnosis of LITA patency by measuring the diastolic components. Conclusion, in diagnosis of LITA patency by the transthoracic ultrasonic cardiography, diagnostic accuracy was improved by measuring the diastolic parameters under continuous infusion of ATP.

Adenosine Triphosphate↗
PubMed1968

Adenosine triphosphate and synchronous mitosis in Physarum polycephalum.

Synchronous mitoses occur in Physarum polycephalum in the absence of cell division. Nucleoside and nucleotide profiles were prepared from synchronously growing P. polycephalum at intervals throughout the growth cycle. Comparison of these profiles demonstrates that the pool of adenosine triphosphate decreases from a high level at prophase to a minimum through mitosis and increases again in the postmitotic period. These events appear to coincide with changes in the pools of adenosine diphosphate and adenosine but not with that of adenosine monophosphate. This observed decrease in the pool of adenosine triphosphate during mitosis was confirmed by direct enzymatic assay. These results presumably reflect the energy demands of the cell during mitosis.

Adenine Nucleotides↗
PubMed2002

Effects of adenosine triphosphate dependent potassium channel opener on bladder overactivity in rats with cerebral infarction.

PURPOSE: We evaluated the effect of the adenosine triphosphate dependent K channel opener KRN2391 (N-cyano-N' -(2-nitroxyethyl)-3-pyridinecarboximidamide methanesulfonate) (Kirin Brewery Co., Gunma, Japan) on bladder overactivity induced by middle cerebral artery occlusion. MATERIALS AND METHODS: At 7 days after implantation of a bladder catheter in male Sprague-Dawley rats a cannula for intracerebroventricular administration was implanted and the left middle cerebral artery was occluded with 4-zero monofilament nylon thread. At 22 hours after the induction of cerebral ischemia saline was infused into the bladder at a constant rate (200 microl. per minute) and a cystometrogram was obtained with the rat in the conscious state. KRN2391 (5 microl.) was administered in intracerebroventricular fashion at graded doses (0.15 to 15 microg.). RESULTS: Bladder capacity in conscious rats was significantly reduced after left middle cerebral artery occlusion. Intracerebroventricular administration of KRN2391 significantly increased bladder capacity in cerebral infarcted but not in sham operated rats. CONCLUSIONS: These results show that a adenosine triphosphate dependent K channel opener may be useful for neurogenic bladder overactivity after cerebral infarction via action on the central nervous system.

Animals↗
PubMedDate not supplied

Reactive oxygen species and human spermatozoa. II. Depletion of adenosine triphosphate plays an important role in the inhibition of sperm motility.

Under moderate conditions, reactive oxygen species (ROS) have been shown to inhibit sperm motility after several hours of incubation. The rapid decrease in flagellar beat frequency observed within the first hour of contact between ROS and spermatozoa was associated with a rapid loss of intracellular adenosine triphosphate (ATP). Motility of intact spermatozoa ceased when their ATP concentration was reduced by 85 +/- 5%. Axonemal damage was confirmed when ROS-treated spermatozoa could not reactivate motility after demembranation in a medium containing magnesium adenosine triphosphate (Mg.ATP). However, in conditions allowing rephosphorylation of the axonemes (addition of cyclic adenosine monophosphate, or cAMP, and protein kinase or sperm extracts to the demembranation medium), the motility could reactivate. Three lines of evidence suggested that ATP depletion induced by ROS treatment was responsible for the effects observed in spermatozoa. First, the rapid decrease in intracellular ATP observed after ROS treatment was closely followed by a decrease in beat frequency, loss of intact sperm motility, and axonemal damage due to insufficient phosphorylation. Second, incubation of spermatozoa with the combination pyruvate-lactate allowed maintenance of sperm ATP at a normal level and prevented the effects of ROS; furthermore, spermatozoa immobilized after ROS treatment, then supplemented with pyruvate-lactate, were able to reinitiate motility in parallel with an increase in their ATP level. Third, treatment of spermatozoa with rotenone, an ATP depleting agent, produced effects similar to ROS treatment and could also be reversed by the addition of pyruvate-lactate. These data are consistent with the conclusion that ROS treatment produced axonemal damage mostly as a result of ATP depletion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1978

Protective effects of adenosine triphosphate administration in burns.

The effects of intramuscular adenosine triphosphate (ATP) administration after thermal skin injury on the ATP content and morphology of the liver and heart were studied in male Sprague-Dawley rats. The results showed that exogenous ATP injected during the early post-burn period could restore the ATP content of the liver and heart to near normal values and modify the burn-related morphological alterations in the liver.

Adenosine Triphosphatases↗
PubMed1979

Effect of divalent metal cations upon the fluorescence and phosphorescence properties of adenosine triphosphate.

The fluorescence and phosphorescence properties of various divalent metal cations and adenosine triphosphate (ATP) dissolved in 1:1 volume by volume of ethylene glycol and water at 77 K have been studied. The present results indicate that Co2+, Ni2+ and Mn2+ quench the phosphorescence of ATP, whereas the fluorescence and the phosphorescence decays are not or only slightly affected. On the other hand, Ca2+ and Mg2+ have no remarkable effect upon the fluorescence and phosphorescence properties.

Adenosine Triphosphate↗
PubMed1981

Erythrocyte 2,3-diphosphoglycerate and adenosine triphosphate in polycythaemia vera.

Erythrocyte 2,3-diphosphoglycerate (2,3-DPG) and adenosine triphosphate (ATP) were measured in 16 patients with polycythaemia vera and found to be normal. The determination of erythrocyte organic phosphate concentration can be helpful in the differential diagnosis of different types of polycythaemia due to the lack of 2,3-DPG rise in patients with polycythaemia vera, as compared to the 2,3-DPG increase usually observed in patients with secondary polycythaemia.

2,3-Diphosphoglycerate↗
PubMedDate not supplied

Effect of adenosine triphosphate and related purines in the rat gastric fundus.

The effect of adenosine triphosphate (ATP) and its analogues was studied in longitudinal muscle strips of the rat gastric fundus in order to characterize the purinoceptors involved. At resting tension, 10(-4) M ATP usually induced a small initial relaxation followed by a contraction; when tone was raised by administration of carbachol (10(-7) M), ATP (10(-4) M) induced a larger relaxation followed by a smaller rebound contraction. Both the contraction at resting tension and the rebound contraction were antagonized by indomethacin. With raised tone, both ATP and 2-methylthioATP induced concentration-dependent relaxations, followed by small rebound contractions, but the slope of the concentration-response curve was very shallow. alpha, beta-MethyleneATP and adenosine induced only concentration-dependent relaxations and the maximal effect was much more pronounced than that of ATP and 2-methyl-thioATP. The rank order of potency of the purines producing relaxation was 2-methylthioATP greater than alpha, beta-methyleneATP greater than ATP greater than adenosine. The relaxant effect of ATP (10(-4) M) at raised tone was clearly antagonized by both reactive blue 2 (10(-4) M) and desensitization to alpha, beta-methyleneATP. It is concluded that the contractile effect of ATP in the rat gastric fundus is due to stimulation of prostaglandin biosynthesis, but identification of the purinoceptor subtype mediating relaxation is problematic and it may differ from the P2x- and P2y-receptors, which are clearly distinguishable in a number of other tissues.

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↗
PubMed1988

Liposomally entrapped adenosine triphosphate. Improved efficiency against experimental brain ischaemia in the rat.

Liposomally entrapped adenosine triphosphate (ATP) was administered intracerebroventricularly and intracarotidally to rats subjected to brain ischaemic episodes by clamping of the carotid arteries and lowering of the systemic blood pressure. It was observed that, when entrapped in liposomes, ATP greatly increased the number of ischaemic episodes before brain electrical silence and death. The results open new perspectives in brain ATP supply, which will potentially be useful in human resuscitation from deep brain hypoergic states.

Adenosine Triphosphate↗
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↗