Measurement of free and bound fractions of extracellular ATP in biological solutions using bioluminescence

Douillet, Christelle; Suy, Sihong; Zarzaur, Ben L.; Robinson, William P.; Milano, Peter M.; Boucher, Richard C.; Rich, Preston B.

doi:10.1002/bio.869

Cited by 11 publications

(7 citation statements)

References 31 publications

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“…Thirdly, previous studies analysed ATP levels in plasma samples that had been frozen and stored, which may have affected the levels. We have recently observed that [ATP] in plasma samples increase after freezing (S. P. Mortensen and Y. Hellsten, unpublished observations), possibly due to ATP release from albumin (Douillet et al 2005). A limitation of the microdialysis technique compared to blood sampling is that sampling is slow such that transient changes cannot be detected.…”

Section: Discussionmentioning

confidence: 99%

Local release of ATP into the arterial inflow and venous drainage of human skeletal muscle: insight from ATP determination with the intravascular microdialysis technique

Mortensen

Thaning

Nyberg

et al. 2011

The Journal of Physiology

101

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Non-technical summary ATP has been proposed to contribute to the local regulation of skeletal muscle blood flow by inducing local vasodilatation. ATP is continuously released, degraded and taken up by cells and the physiological levels are therefore difficult to determine. In the present investigation, we used a novel technique involving microdialysis probes to determine plasma ATP levels in blood vessels supplying and draining resting and contracting human skeletal muscle and to investigate the stimuli for ATP release. The results show a local release of ATP into arterial and venous blood. In addition, we found that thigh compression is a stimulus for ATP release. Furthermore, we find that the half-life of ATP in arterial blood is <1 s.Abstract Intraluminal ATP could play an important role in the local regulation of skeletal muscle blood flow, but the stimuli that cause ATP release and the levels of plasma ATP in vessels supplying and draining human skeletal muscle remain unclear. To gain insight into the mechanisms by which ATP is released into plasma, we measured plasma [ATP] with the intravascular microdialysis technique at rest and during dynamic exercise (normoxia and hypoxia), passive exercise, thigh compressions and arterial ATP, tyramine and ACh infusion in a total of 16 healthy young men. Femoral arterial and venous [ATP] values were 109 ± 34 and 147 ± 45 nmol l −1 at rest and increased to 363 ± 83 and 560 ± 111 nmol l −1 , respectively, during exercise (P < 0.05), whereas these values did not increase when exercise was performed with the other leg. Hypoxia increased venous plasma [ATP] at rest compared to normoxia (P < 0.05), but not during exercise. Arterial ATP infusion (≤1.8 μmol min −1 ) increased arterial plasma [ATP] from 74 ± 17 to 486 ± 82 nmol l −1 (P < 0.05), whereas it remained unchanged in the femoral vein at ∼150 nmol l −1 . Both arterial and venous plasma [ATP] decreased during acetylcholine infusion (P < 0.05). Rhythmic thigh compressions increased arterial and venous plasma [ATP] compared to baseline conditions, whereas these values did not change during passive exercise or tyramine infusion. These results demonstrate that ATP is released locally into arterial and venous plasma during exercise and during hypoxia at rest. Compression of the vascular system could contribute to the increase during exercise whereas there appears to be little ATP release in response to increased blood flow, vascular stretch or sympathetic ATP release. Furthermore, the half-life of arterially infused ATP is <1 s.

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Section: Discussionmentioning

confidence: 99%

Local release of ATP into the arterial inflow and venous drainage of human skeletal muscle: insight from ATP determination with the intravascular microdialysis technique

Mortensen

Thaning

Nyberg

et al. 2011

The Journal of Physiology

101

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“…The endogenous free plasma ATP concentration has been measured as 93 Ϯ 27 nM in rats (6). Using a dialysate measurement, the basal interstitial fluid ATP concentration has been estimated to be 38 Ϯ 8 nM in the in situ rat heart (16).…”

Section: Discussionmentioning

confidence: 99%

P2X purinergic receptor-mediated ionic current in cardiac myocytes of calsequestrin model of cardiomyopathy: implications for the treatment of heart failure

Shen

Cronin²,

Sonin³

et al. 2007

American Journal of Physiology-Heart and Circulatory Physiology

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BT. P2X purinergic receptormediated ionic current in cardiac myocytes of calsequestrin model of cardiomyopathy: implications for the treatment of heart failure. Am J Physiol Heart Circ Physiol 292: H1077-H1084, 2007. First published October 13, 2006; doi:10.1152/ajpheart.00515.2006.-P2X purinergic receptors, activated by extracellular ATP, mediate a number of cardiac cellular effects and may be important under pathophysiological conditions. The objective of the present study was to characterize the P2X receptor-mediated ionic current and determine its role in heart failure using the calsequestrin (CSQ) model of cardiomyopathy. Membrane currents under voltage clamp were determined in myocytes from both wild-type (WT) and CSQ mice. The P2X agonist 2-methylthio-ATP (2-meSATP) induced an inward current that was greater in magnitude in CSQ than in WT ventricular cells. The novel agonist, MRS-2339, an N-methanocarba derivative of 2-chloro-AMP relatively resistant to nucleotidase, induced a current in the CSQ myocyte similar to that by 2-meSATP. When administered via a miniosmotic pump (Alzet), it significantly increased longevity compared with vehicle-injected mice (log rank test, P ϭ 0.02). The improvement in survival was associated with decreases in the heart weight-to-body weight ratio and in cardiac myocyte cross-sectional area [MRS-2339-treated mice: 281 Ϯ 15.4 (SE) m 2 , n ϭ 6 mice vs. vehicle-treated mice: 358 Ϯ 27.8 m 2 , n ϭ 6 mice, P Ͻ 0.05]. MRS-2339 had no vasodilator effect in mouse aorta ring preparations, indicating that its salutary effect in heart failure is not because of any vascular unloading. The cardiac P2X current is upregulated in the CSQ heart failure myocytes. Chronic administration of a nucleotidaseresistant agonist confers a beneficial effect in the CSQ model of heart failure, apparently via an activation of the cardiac P2X receptor. Cardiac P2X receptors represent a novel and potentially important therapeutic target for the treatment of heart failure. ion channels; membrane current; mouse; heart RECEPTORS FOR PURINE nucleotides, known as P2 purinergic receptors, mediate a number of potent and possibly important biological effects in the cardiovascular system (20,22,29). The P2X ion channels are receptor channels activated by extracellular ATP, whereas the P2Y receptors are G proteincoupled receptors. Together, they represent two subfamilies of the P2 nucleotide receptors. Previous studies have shown that extracellular ATP can cause an ionic current in murine (27), rat (26), and guinea pig (21) cardiac ventricular myocytes. The receptor that mediates this current appears to be a P2X receptor, of which the P2X 4 receptor is an important subunit (27). Activation of P2X receptors leads to the opening of a nonselective cation channel permeable to Na ϩ , K ϩ , and Ca 2ϩ . The current is inward at negative membrane potentials, reverses near 0 mV, and becomes outward at positive potentials. The continuous activation of this receptor channel by endogenous extracellular ATP may assume an important b...

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“…The current assay recovers 96.2% of exogenously added ATP (14 ). Some plasma ATP is bound to albumin and is not detected by the luciferin-luciferase assay (39 ). In rat plasma, heat denaturation increased average plasma ATP concentration from 93 to 150 nmol/L (39 ).…”

Section: Clinical Chemistry 53 No 2 2007mentioning

confidence: 95%

Human Plasma ATP Concentration

2007

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Background: Human plasma ATP concentration is reported in many studies as roughly 1000 nmol/L. The present study tested the hypothesis that the measured plasma ATP concentration is lower if ATP release from formed blood elements is inhibited during blood sample processing. A second hypothesis was that pretreatment with aspirin to inhibit platelets would reduce the measured plasma concentration of ATP.

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Measurement of free and bound fractions of extracellular ATP in biological solutions using bioluminescence

Cited by 11 publications

References 31 publications

Local release of ATP into the arterial inflow and venous drainage of human skeletal muscle: insight from ATP determination with the intravascular microdialysis technique

Local release of ATP into the arterial inflow and venous drainage of human skeletal muscle: insight from ATP determination with the intravascular microdialysis technique

P2X purinergic receptor-mediated ionic current in cardiac myocytes of calsequestrin model of cardiomyopathy: implications for the treatment of heart failure

Human Plasma ATP Concentration

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