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CARDIOVASCULAR
Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri
Received December 19, 2003; accepted February 5, 2004.
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Abstract |
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; Sprague et al., 1996). The release of ATP from intracellular stores into the surrounding environment is reported to occur in response to distinct physiological stimuli. One such stimulus, mechanical deformation, can occur as the erythrocyte passes through small resistance vessels and capillaries of the microcirculation or in response to increases in linear flow velocity. Sprague et al. (1996) reported that both rabbit and human erythrocytes release ATP in response to mechanical deformation produced by passage of erythrocytes through filters with an average pore size of 5 µm. Human and hamster erythrocytes have also been reported to release ATP in response to decreased oxygen tension and/or reduced pH (Bergfeld and Forrester, 1992; Ellsworth et al., 1995), environments the erythrocyte would encounter as it traverses skeletal muscle and other oxygen-consuming organs.
Once released from the erythrocyte into the circulation, ATP can activate purinergic receptors, specifically those of the P2y subfamily, present on the vascular endothelium, resulting in the synthesis and release of NO. NO released abluminally interacts with vascular smooth muscle, resulting in its relaxation. The resultant increase in vascular caliber would decrease the stimulus for deformation-induced ATP release. An increase in vascular caliber would also decrease ATP release in response to decreased oxygen tension by increasing oxygen delivery to the tissue, resulting in improved matching of oxygen supply with metabolic demand (Ellsworth, 2000).
In addition to being released abluminally, NO is released luminally where it can interact directly with formed elements in the blood, including the erythrocyte. NO is a highly reactive free radical that has been identified as a regulatory molecule in a number of systems, including, but not limited to, the immune, nervous and cardiovascular systems (Garthwaite, 1991; Bredt and Snyder, 1994; Garthwaite and Boulton, 1995). NO regulates these systems by stimulating or inhibiting the activity of several proteins (Garthwaite, 1991; Bredt and Snyder, 1994; Garthwaite and Boulton, 1995). Therefore, it is possible that luminal release of NO could interact with circulating erythrocytes, modulating their release of ATP.
In the present studies, we investigate the hypothesis that NO functions in a negative feedback manner to inhibit ATP from circulating erythrocytes. We determined the effect of increasing concentrations of N-(2-aminoethyl-N-(2-hydroxy-2-nitrosohydrazino)-1,2-ethylenediamine (spermine NONOate), a NO donor, on total pulmonary vascular resistance in the isolated rabbit lung. In addition, we investigated the effect of spermine NONOate on ATP release in response to decreased oxygen tension and mechanical deformation. Finally, we examined the effect of spermine, the polyamine remaining after the liberation of NO from spermine NONOate, on ATP release in response to decreased oxygen tension, as well as the effect of NO-depleted spermine NONOate on mechanical deformation-induced ATP release from erythrocytes.
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Materials and Methods |
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Isolation of Rabbit and Human Erythrocytes. Rabbits were anesthetized, ventilated, and exsanguinated as described above. Human erythrocytes were obtained by venipuncture performed in an antecubital vein without the use of a tourniquet. Sixty milliliters of blood were collected into a syringe containing 50 U of heparin. Protocols used to obtain rabbit and human blood were approved by the Institutional Animal Care and Use Committee and the Institutional Review Board of Saint Louis University, respectively.
Rabbit or human blood was centrifuged at 500g for 10 min at 4°C. The plasma, buffy coat, and uppermost erythrocytes were removed by aspiration and discarded. The remaining erythrocytes were washed three times in buffer solution containing 140.5 mM NaCl, 21.0 mM Tris-HCl, 4.7 mM KCl, 2.0 mM CaCl2, 1.2 mM MgSO4, 0.1% dextrose, and 0.5% bovine albumin, fraction V (ICN Biomedicals, Aurora, OH), final pH 7.4. The hematocrit of the washed erythrocytes was determined using an Autocrit Ultra 3 centrifuge (BD Biosciences, Bedford, MA).
Decreased Oxygen Tension-Induced ATP Release. Washed rabbit or human erythrocytes were brought to a 10% hematocrit with a buffered solution containing 140.5 mM NaCl, 21.0 mM Tris-HCl, 4.7 mM KCl, 2.0 mM CaCl2, 1.2 mM MgSO4, and 0.5% dextrose, pH 7.4. The resuspended erythrocytes were then diluted to a 0.1% hematocrit with buffered solution in a tissue chamber set at 37°C. The buffered solution in each tissue chamber was equilibrated with either 15% O2,6%CO2, 79% N2 (PO2 = 100-110 mm Hg, PCO2 = 30-32 mm Hg, pH 7.38 ± 0.01) or 0% O2,6%CO2, 94% N2 (PO2 = 35-40 mm Hg, PCO2 = 30-32 mm Hg, pH 7.38 ± 0.01). Immediately after the addition of the erythrocytes to the tissue chamber, the chamber was covered and the gas turned off. The ATP released into the buffered solution was measured 1 min after the addition of the erythrocytes to the chamber. The pH and gas tensions were determined immediately after the measurement of ATP, using a blood-gas analyzer (Radiometer, Bronshoj, Denmark).
Mechanical Deformation of Washed Erythrocytes. Washed rabbit erythrocytes were brought to 10% hematocrit with a physiological salt solution containing 140.5 mM NaCl, 21.0 mM Tris-HCl, 4.7 mM KCl, 2.0 mM CaCl2, 1.2 mM MgSO4, 0.1% dextrose, and 0.5% bovine albumin (pH 7.4) and then subjected to mechanical deformation using the St. George's blood filtrometer (Carri-Med Ltd., Dorking, UK). As described previously, this device creates a calibrated pressure gradient across a vertically mounted filter with pores having an average diameter of 5 µm (Sprague et al., 1996). Deformation was achieved by passing the suspended erythrocytes through the filter. The red cell transit time, a measure of erythrocyte deformability, as well as the concentration of ATP in the filter effluent were determined.
Measurement of ATP. ATP was measured using the luciferinluciferase technique (Strehler, 1968). A 200-µl sample of an erythrocyte suspension was injected into a cuvette containing 100 µl of a 1 mg/ml crude firefly-tail extract (Sigma-Aldrich, St. Louis, MO) and 100 µl of a 0.5 mg/ml solution of D-luciferin (Sigma-Aldrich). The addition of D-luciferin to the reaction mixture increases the sensitivity of the assay (Bergfeld and Forrester, 1992). The light emitted from the reaction of ATP with the crude firefly extract/D-luciferin was measured using a luminometer set at a wavelength of 565 nm (model TD-20/20; Turner Designs, Sunnyvale, CA). The emission peak was compared with an ATP standard curve generated on the day of the experiment. The concentration of ATP was determined by comparing the sample signal with that of the standard curve. We have established that standard curves run in the absence of erythrocytes are not different from those run in the presence of nonstimulated erythrocytes. Spermine NONOate, at the concentrations used in these experiments, did not alter the ATP signal.
Measurement of Erythrocyte Lysis. To exclude the possibility that erythrocyte lysis contributes to the measurement of ATP release, after measuring ATP in the erythrocyte suspension, erythrocytes were sedimented by centrifugation at 500g for 10 min. The presence of hemoglobin in the supernatant was determined by light absorption at 405 nm (van Kampen and Zijlstra, 1983).
To ensure that the method used to detect erythrocyte lysis is as sensitive as the assay used to measure ATP release, washed rabbit erythrocytes were lysed and serial dilutions made. The concentration of ATP and the absorbance at 405 nm was measured for each dilution. In dilutions where ATP was measured, an absorbance at 405 nm was also detected, verifying that the assay used to measure erythrocyte lysis is as sensitive as the assay used to measure ATP release.
Statistical Methods. Statistical significance between experimental periods was determined with an analysis of variance, or where appropriate a student's t test. When using an analysis of variance, a least significant difference test was used to identify individual differences, in the event that the F ratio indicated that changes had occurred. P values of 0.05 or less were considered statistically significant. Results are reported as means ± S.E.M.
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Results |
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Effect of Spermine NONOate on ATP Release from Erythrocytes in Response to Decreased Oxygen Tension. To demonstrate that NO inhibits ATP release in response to decreased oxygen tension, washed rabbit erythrocytes were incubated with the NO donor spermine NONOate (100 nM, 20 min) and then exposed to either a normal or a decreased oxygen tension. As illustrated in Fig. 2A, preincubation of rabbit erythrocytes with spermine NONOate inhibited ATP release in response to decreased oxygen tension. In separate experiments, spermine NONOate also inhibited ATP release from human erythrocytes in response to decreased oxygen tension (Fig. 2B). In experiments using rabbit or human erythrocytes, there was no measurable difference in the total intracellular concentration of ATP between erythrocytes treated with spermine NONOate and those that were untreated (rabbit: 1.2 x 10-3 M and 1.2 x 10-3 M ATP; human: 1.6 x 10-3 M and 1.9 x 10-3 M ATP for untreated and spermine NONOate treated erythrocytes, respectively). Importantly, increases in ATP release measured from both rabbit and human erythrocytes were not the result of erythrocyte lysis, because free hemoglobin was not detected in any of the samples.
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Basal ATP release is measured when erythrocytes are exposed to a normal oxygen tension (Fig. 2). To determine whether spermine NONOate could inhibit the basal release of ATP, washed rabbit erythrocytes were incubated with spermine NONOate (100 nM, 20 min) and then exposed to a normal oxygen tension. Spermine NONOate had no effect on basal release of ATP (15.9 ± 2.7 versus 17.4 ± 4.1 nM ATP per 2 x 104 erythrocytes/mm3 for untreated and spermine NONOate treated erythrocytes, respectively; n = 4). It is possible that the ATP measured under a normal oxygen tension is the result of the method used to obtain erythrocytes.
Effect of Spermine on ATP Release from Erythrocytes in Response to Decreased Oxygen Tension. Spermine NONOate is synthesized by exposing a nucleophilic species, spermine, to NO in the absence of oxygen. This process yields the stable NO donor in powdered form. When spermine NONOate is dissolved it dissociates to regenerate NO and the nucleophilic species, spermine, as a by-product. Although the by-products of most NO donors are inactive in most biological systems, it is not known whether the byproduct of spermine NONOate, spermine, can influence ATP release from erythrocytes. To ensure that the inhibition in ATP release in response to decreased oxygen tension resulted from the action of NO and not spermine, washed rabbit erythrocytes were incubated with spermine and then exposed to either a normal or decreased oxygen tension. As described in Fig. 3, spermine had no effect on ATP release from rabbit erythrocytes in response to decreased oxygen tension. Incubating rabbit erythrocytes with spermine did not alter intracellular concentrations of ATP (1.6 x 10-3 ± 2.4 x 10-4 M ATP for untreated erythrocytes versus 1.7 x 10-3 ± 3.1 x 10-4 M ATP for treated erythrocytes) or induce erythrocyte lysis.
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Effect of Spermine NONOate on ATP Release from Erythrocytes in Response to Mechanical Deformation. To provide support for the hypothesis that NO inhibits ATP release from erythrocytes and that this inhibition is not unique to decreased oxygen tension, washed rabbit erythrocytes were incubated with spermine NONOate (100 nM, 20 min) and then mechanically deformed by passage through filters with a pore size of 5 µm using the St. George's blood filtrometer. As depicted in Fig. 4A, spermine NONOate inhibited mechanical deformation-induced ATP release from rabbit erythrocytes. In these experiments, incubating rabbit erythrocytes with spermine NONOate did not alter erythrocyte deformability or intracellular concentrations of ATP. In addition, increases in ATP were not the result of erythrocyte lysis as increases in free hemoglobin were not detected in any of the samples.
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Effect of NO-Depleted Spermine NONOate on Mechanical Deformation-Induced ATP Release from Erythrocytes. To ensure that the inhibition of mechanical deformation-induced ATP release was not the result of the by-product formed from the liberation of NO, washed rabbit erythrocytes were incubated with NO-depleted spermine NONOate. In these experiments, spermine NONOate was dissolved in aqueous solution 12 h before its use. This time interval allows for the complete liberation of NO, leaving only the degradation product. Washed rabbit erythrocytes were incubated with the NO-depleted spermine NONOate and then mechanically deformed. The NO-depleted donor had no effect on mechanical deformation-induced ATP release (Fig. 4B). In addition, incubation of erythrocytes with spermine NONOate did not alter the red cell transit time, indicating that incubating with NO-depleted spermine NONOate did not alter erythrocyte deformability. This provides support for the hypothesis that NO itself, not the by-product resulting from the liberation of NO, inhibits ATP release from erythrocytes in response to mechanical deformation.
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Discussion |
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TopAbstractMaterials and MethodsResultsDiscussionReferences |
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; Ellsworth et al., 1995; Sprague et al., 1996). Previously, we reported that ATP released from erythrocytes in the pulmonary circulation produced decreases in vascular resistance via stimulation of endogenous NO synthesis (Sprague et al., 1996). NO that is released abluminally from the endothelium interacts with vascular smooth muscle, resulting in vasorelaxation. However, NO is also released into the vascular lumen where it can interact directly with formed elements in the blood, including the erythrocyte. In the present study, we hypothesize that NO released luminally from the vascular endothelium in response to erythrocyte-derived ATP serves as a signal to inhibit additional ATP release from circulating erythrocytes.
Addition of the NO donor spermine NONOate to the perfusate of isolated rabbit lungs in which the pulmonary vascular resistance is increased with 5-HT resulted in a concentration-dependent decrease in total pulmonary vascular resistance (Fig. 1). In identical experiments, spermine, the polyamine remaining from the liberation of NO from spermine NONOate, had no effect on total pulmonary vascular resistance. These experiments demonstrate that NO liberated from spermine NONOate can influence vascular reactivity and serve to identify a physiologically relevant dose of spermine NONOate (100 nM) used in subsequent experiments. Concentrations of NO in the nanomolar range are consistent with previously reported measurements from endothelial cells in vitro and in vivo (Kalinowski et al., 2001; Balbatun et al., 2003; Kalinowski et al., 2003). Spermine NONOate, but not spermine, the polyamine remaining from the liberation of NO from spermine NONOate, inhibited ATP release from rabbit and human erythrocytes in response to decreased oxygen tension (Figs. 2 and 3, respectively). In separate experiments, spermine NONOate, but not NO-depleted spermine NONOate, inhibited ATP release in response to mechanical deformation (Fig. 4). Together, these data provide support for the hypothesis that NO inhibits ATP release from erythrocytes.
The ability of NO to serve as a regulatory molecule is not limited to the inhibition of ATP release from erythrocytes. NO has been identified as an important regulatory molecule in other systems, including the immune, nervous, and cardiovascular systems (Garthwaite, 1991; Bredt and Snyder, 1994; Garthwaite and Boulton, 1995). NO can regulate these systems by stimulating or inhibiting the activity of several proteins (Garthwaite, 1991; Bredt and Snyder, 1994; Garthwaite and Boulton, 1995). Among these proteins are adenylyl cyclase and the heterotrimeric G protein Gi, both of which are components of a proposed signal transduction pathway for ATP release from erythrocytes (Sprague et al., 2001; Olearczyk et al., 2003). NO gas as well as the NO donors 3-morpholinosydnonimine and S-nitroso-N-acetlypenicillamine were reported to directly inhibit the catalytic activity of adenylyl cyclase types V and VI, but not other types of adenylyl cyclase (Tao et al., 1992; Duhe et al., 1994; McVey et al., 1999; Hill et al., 2000). Inhibition of adenylyl cyclase activity by NO was proposed to result from S-nitrosylation. S-Nitrosylation is the nonenzymatic addition of NO to a protein thiol, a cysteine residue in the case of adenylyl cyclase (Stamler, 1994). Therefore, if the adenylyl cyclase in the proposed signal transduction pathway for ATP release from erythrocytes is type V or type VI, NO could inhibit ATP release via S-nitrosylation.
In addition to inhibiting adenylyl cyclase activity, NO has also been reported to indirectly inhibit the activity of the heterotrimeric G protein Gi/o (Brune and Lapetina, 1989; Dimmeler and Brune, 1991; Pozdnyakov et al., 1997). Incubating the cytosolic or membrane fractions from a variety of cell types with NO gas or various NO donors in the presence of [32P]NAD increased the 32P-labeling of several proteins, including the heterotrimeric G protein Gi/o (Pozdnyakov et al., 1993; Sheffler et al., 1995; Zoche and Koch, 1995; Sullivan et al., 1997). This action of NO resulted from the stimulation of an endogenous mono-ADP-ribosyltransferase, an enzyme that catalyzes the addition of the ADP-ribose moiety from nicotinamide adenine dinucleotide to protein (Brune and Lapetina, 1989; Dimmeler and Brune, 1991; Schuman et al., 1994). An endogenous mono-ADP-ribosyltransferase has been identified and purified from the cytosol of human erythrocytes (Tanuma et al., 1988). This mono-ADP-ribosyltransferase mono-ADP-ribosylates the 
-subunit of Gi/o. We have identified the heterotrimeric G proteins Gi1, Gi2 and Gi3 but not Go in rabbit and human erythrocyte membranes (Olearczyk et al., 2003). The identification of an endogenous mono-ADP-ribosyltransferase in erythrocytes that ADP-ribosylates Gi and that may be activated by NO suggests a second possible mechanism for the regulation of ATP release from erythrocytes.
The ability of NO to directly inhibit adenylyl cyclase activity and/or indirectly inhibit the activity of the heterotrimeric G protein Gi/o, via stimulation of an endogenous mono-ADP-ribosyltransferase, is consistent with the hypothesis that NO inhibits a signal transduction pathway for ATP release from erythrocytes. Under this regulatory mechanism, ATP released from the erythrocyte, in response to mechanical deformation or decreased oxygen tension, would activate P2y receptors located on the vascular endothelium, stimulating the synthesis and bidirectional release of NO. NO released abluminally would result in relaxation of vascular smooth muscle, thereby increasing vascular caliber and decreasing mechanical deformation-induced ATP release. In addition, an increase in vascular caliber would decrease ATP release in response to decreased oxygen tension by increasing oxygen delivery to the tissue, thereby matching oxygen supply with metabolic demand. The NO released luminally would interact with the erythrocyte where it could directly inhibit adenylyl cyclase activity and/or indirectly inhibit the activity of Gi/o via stimulation of an endogenous mono-ADP-ribosyltransferase. Either action of NO would be expected to inhibit a signal transduction pathway for ATP release from erythrocytes and thereby identifies an additional role of NO in the regulation of vascular resistance.
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Acknowledgements |
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Footnotes |
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ABBREVIATIONS: NO, nitric oxide; spermine NONOate, N-(2-aminoethyl)-N-(2-hydroxy-2-nitrosohydrazino)-1,2-ethylenediamine; Ppa, pulmonary arterial pressure; Pla, left atrial pressure, Paw, airway pressure; 5-HT, 5-hydroxytryptamine.
Address correspondence to: Dr. Jeffrey J. Olearczyk, Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, 1402 South Grand Blvd., St. Louis, MO 63104. E-mail: olearcjj{at}slu.edu
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References |
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TopAbstractMaterials and MethodsResultsDiscussionReferences |
|---|
Balbatun A, Louka FR, and Malinski T (2003) Dynamics of nitric oxide release in the cardiovascular system. Acta Bioch Pol 50: 61-68.
Bergfeld GR and Forrester T (1992) Release of ATP from human erythrocytes in response to a brief period of hypoxia and hypercapnia. Cardiovasc Res 26: 40-47.
Bredt DS and Snyder SH (1994) Nitric oxide: a physiologic messenger molecule. Annu Rev Biochem 63: 175-195.[CrossRef][Medline]
Brune B and Lapetina EG (1989) Activation of a cytosolic ADP-ribosyltransferase by nitric oxide-generating agents. J Biol Chem 264: 8455-8458.
Dimmeler S and Brune B (1991) L-arginine stimulates an endogenous ADP-ribosyltransferase. Biochem Biophys Res Commun 178: 848-855.[CrossRef][Medline]
Duhe RJ, Nielsen MD, Dittman AH, Villacres EC, Choi EJ, and Storm DR (1994) Oxidation of critical cysteine residues of type I adenylyl cyclase by oiodosobenzoate or nitric oxide reversibly inhibits stimulation by calcium and calmodulin. J Biol Chem 269: 7290-7296.
Ellsworth ML (2000) The red blood cell as an oxygen sensor: what is the evidence? Acta Physiol Scand 168: 551-559.[CrossRef][Medline]
Ellsworth ML, Forrester T, Ellis CG, and Dietrich HH (1995) The erythrocyte as a regulator of vascular tone. Am J Physiol 269: H2155-H2161.
Garthwaite J (1991) Glutamate, nitric oxide and cell-cell signalling in the nervous system. Trends Neurosci 14: 60-67.[CrossRef][Medline]
Garthwaite J and Boulton CL (1995) Nitric oxide signaling in the central nervous system. Annu Rev Physiol 57: 683-706.[CrossRef][Medline]
Hill J, Howlett A, and Klein C (2000) Nitric oxide selectively inhibits adenylyl cyclase isoforms 5 and 6. Cell Signal 12: 233-237.[CrossRef][Medline]
Kalinowski L, Dobrucki LW, and Malinski T (2001) Nitric oxide as a second messenger in parathyroid hormone-related protein signaling. J Endocrinol 170: 433-440.[Abstract]
Kalinowski L, Dobrucki LW, Szczepanska-Konkel M, Jankowski M, Martyniec L, Angielski S, and Malinski T (2003) Third-generation beta-blockers stimulate nitric oxide release from endothelial cells through ATP efflux: a novel mechanism for antihypertensive action. Circulation 107: 2747-2752.
McVey M, Hill J, Howlett A, and Klein C (1999) Adenylyl cyclase, a coincidence detector for nitric oxide. J Biol Chem 274: 18887-18892.
Olearczyk JJ, Stephenson AH, Lonigro AJ, and Sprague RS (2003) The heterotrimeric G protein Gi is involved in a signal transduction pathway for ATP release from erythrocytes. Am J Physiol Heart Circ Physiol 286: H940-H945.
Pozdnyakov N, Lloyd A, Reddy VN, and Sitaramayya A (1993) Nitric oxide-regulated endogenous ADP-ribosylation of rod outer segment proteins. Biochem Biophys Res Commun 192: 610-615.[CrossRef][Medline]
Pozdnyakov N, Margulis A, and Sitaramayya A (1997) Endogenous ADP-ribosylation of a G(alpha i) protein in bovine ciliary body is stimulated by nitric oxide. Biochem Biophys Res Commun 235: 482-486.[CrossRef][Medline]
Schuman EM, Meffert MK, Schulman H, and Madison DV (1994) An ADP-ribosyltransferase as a potential target for nitric oxide action in hippocampal long-term potentiation. Proc Natl Acad Sci USA 91: 11958-11962.
Sheffler LA, Wink DA, Melillo G, and Cox GW (1995) Characterization of nitric oxide-stimulated ADP-ribosylation of various proteins from the mouse macrophage cell line ANA-1 using sodium nitroprusside and the novel nitric oxide-donating compound diethylamine dinitric oxide. J Leukoc Biol 57: 152-159.[Abstract]
Sprague RS, Ellsworth ML, Stephenson AH, and Lonigro AJ (1996) ATP: the red blood cell link to NO and local control of the pulmonary circulation. Am J Physiol 271: H2717-H2722.
Sprague RS, Ellsworth ML, Stephenson AH, and Lonigro AJ (2001) Participation of cAMP in a signal-transduction pathway relating erythrocyte deformation to ATP release. Am J Physiol 281: C1158-C1164.
Stamler JS (1994) Redox signaling: nitrosylation and related target interactions of nitric oxide. Cell 78: 931-936.[CrossRef][Medline]
Strehler BL (1968) Bioluminescence assay: principles and practice. Methods Biochem Anal 16: 99-181.[CrossRef][Medline]
Sullivan BM, Wong S, and Schuman EM (1997) Modification of hippocampal synaptic proteins by nitric oxide-stimulated ADP ribosylation. Learn Mem 3: 414-424.
Tanuma S, Kawashima K, and Endo H (1988) Eukaryotic mono(ADP-ribosyl)transferase that ADP-ribosylates GTP-binding regulatory Gi protein. J Biol Chem 263: 5485-5489.
Tao Y, Howlett A, and Klein C (1992) Nitric oxide stimulates the ADP-ribosylation of a 41-kDa cytosolic protein in Dictyostelium discoideum. Proc Natl Acad Sci USA 89: 5902-5906.
van Kampen EJ and Zijlstra WG (1983) Spectrophotometry of hemoglobin and hemoglobin derivatives. Adv Clin Chem 23: 199-257.[Medline]
Zoche M and Koch KW (1995) Purified retinal nitric oxide synthase enhances ADP-ribosylation of rod outer segment proteins. FEBS Lett 357: 178-182.[CrossRef][Medline]
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, P < 0.01, different from 1 and 10 nM spermine NONOate; 
