Abstract
Nitroglycerin (NTG), the agent most commonly used to treat acute angina pectoris, is a vasodilator whose mechanism of action remains unknown. We hypothesized that NTG might induce endothelial cells to synthesize prostacyclin (PGI2), a known vasodilator and inhibitor of platelet aggregation. Therefore, cultured human endothelial cells were incubated with NTG at various concentrations for 1-3 min. PGI2 biologic activity in the endothelial cell supernates was assayed by inhibition of platelet aggregation in vitro. The concentration of 6-keto-PGF1α, the stable hydrolysis product of PGI2, was measured by specific radioimmunoassay.
NTG alone significantly inhibited platelet aggregation and thromboxane A2 synthesis only at suprapharmacologic concentrations (≥1 μg/ml). However, when NTG at clinically attainable concentrations (0.1-10 ng/ml) was incubated with endothelial cells, the endothelial cell supernates inhibited platelet aggregation in a dose-dependent manner. The inhibitor was heat labile. Radioimmunoassay of the endothelial cell supernates for 6-keto-PGF1α demonstrated that NTG elicited dose-dependent increments in the synthesis of PGI2 by endothelial cells, ranging from 13% at NTG 10 pg/ml to 63% at NTG 10 ng/ml (P < 0.01, n = 10). Pretreatment of endothelial cells with either aspirin (50 μM for 120 min) or the prostacyclin synthetase inhibitor 15-hydroperoxyarachidonic acid (20 μg/ml for 15 min) abolished production of the platelet inhibitory substance. Synergy between NTG and PGI2 in the inhibition of platelet aggregation was not present at clinically attainable concentrations of NTG.
Thus, NTG at clinically attainable concentrations causes a dose-dependent increase in PGI2 synthesis by endothelial cells. If this phenomenon occurs in vivo, the PGI2 produced could ameliorate myocardial ischemia by causing peripheral vasodilation and decreasing cardiac work, inhibiting platelet aggregation and thromboxane A2 synthesis, and possibly reversing coronary artery vasospasm.
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- Amezcua J. L., O'Grady J., Salmon J. A., Moncada S. Prolonged paradoxical effect of aspirin on platelet behaviour and bleeding time in man. Thromb Res. 1979;16(1-2):69–79. doi: 10.1016/0049-3848(79)90270-6. [DOI] [PubMed] [Google Scholar]
- Armstrong J. M., Lattimer N., Moncada S., Vane J. R. Comparison of the vasodepressor effects of prostacyclin and 6-oxo-prostaglandin F1alpha with those of prostaglandin E2 in rats and rabbits. Br J Pharmacol. 1978 Jan;62(1):125–130. doi: 10.1111/j.1476-5381.1978.tb07014.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Armstrong P. W., Armstrong J. A., Marks G. S. Blood levels after sublingual nitroglycerin. Circulation. 1979 Mar;59(3):585–588. doi: 10.1161/01.cir.59.3.585. [DOI] [PubMed] [Google Scholar]
- Armstrong P. W., Armstrong J. A., Marks G. S. Pharmacokinetic-hemodynamic studies of intravenous nitroglycerin in congestive cardiac failure. Circulation. 1980 Jul;62(1):160–166. doi: 10.1161/01.cir.62.1.160. [DOI] [PubMed] [Google Scholar]
- Axelsson K. L., Wikberg J. E., Andersson R. G. Relationship between nitroglycerin, cyclic GMP and relaxation of vascular smooth muscle. Life Sci. 1979 May 7;24(19):1779–1786. doi: 10.1016/0024-3205(79)90067-5. [DOI] [PubMed] [Google Scholar]
- Baaske D. M., Amann A. H., Wagenknecht D. M., Mooers M., Carter J. E., Hoyt H. J., Stoll R. G. Nitroglycerin compatibility with intravenous fluid filters, containers, and administration sets. Am J Hosp Pharm. 1980 Feb;37(2):201–205. [PubMed] [Google Scholar]
- Blumenthal H. P., Fung H. L., McNiff E. F., Yap S. K. Plasma nitroglycerin levels after sublingual, oral and topical administration. Br J Clin Pharmacol. 1977 Apr;4(2):241–242. doi: 10.1111/j.1365-2125.1977.tb00703.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bogaert M. G., Rosseel M. T. Plasma levels in man of nitroglycerin after buccal administration. J Pharm Pharmacol. 1972 Sep;24(9):737–738. doi: 10.1111/j.2042-7158.1972.tb09100.x. [DOI] [PubMed] [Google Scholar]
- Burns T. S., Saunders R. N. Antiplatelet activity of hydralazine. Thromb Res. 1979;16(5-6):837–842. doi: 10.1016/0049-3848(79)90227-5. [DOI] [PubMed] [Google Scholar]
- Crutchley D. J., Ryan U. S., Ryan J. W. Effects of aspirin and dipyridamole on the degradation of adenosine diphosphate by cultured cells derived from bovine pulmonary artery. J Clin Invest. 1980 Jul;66(1):29–35. doi: 10.1172/JCI109831. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Di Minno G., Silver M. J., de Gaetano G. Prostaglandins as inhibitors of human platelet aggregation. Br J Haematol. 1979 Dec;43(4):637–647. doi: 10.1111/j.1365-2141.1979.tb03797.x. [DOI] [PubMed] [Google Scholar]
- Diamond J., Blisard K. S. Effects of stimulant and relaxant drugs on tension and cyclic nucleotide levels in canine femoral artery. Mol Pharmacol. 1976 Jul;12(4):668–692. [PubMed] [Google Scholar]
- Feigen L. P., Chapnick B. M., Flemming J. E., Kadowitz P. J. Prostaglandins: renal vascular responses to bradykinin, histamine, and nitroglycerine. Am J Physiol. 1978 Apr;234(4):H496–H502. doi: 10.1152/ajpheart.1978.234.4.H496. [DOI] [PubMed] [Google Scholar]
- Fitzpatrick F. A., Gorman R. R. A comparison of imidazole and 9,11-azoprosta-5,13-dienoic acid. Two selective thromboxane synthetase inhibitors. Biochim Biophys Acta. 1978 Mar 1;539(2):162–172. doi: 10.1016/0304-4165(78)90003-x. [DOI] [PubMed] [Google Scholar]
- Fitzpatrick F. A., Gorman R. R., Mc Guire J. C., Kelly R. C., Wynalda M. A., Sun F. F. A radioimmunoassay for thromboxane B2. Anal Biochem. 1977 Sep;82(1):1–7. doi: 10.1016/0003-2697(77)90127-0. [DOI] [PubMed] [Google Scholar]
- Förster W. Significance of prostaglandins and thromboxane A2 for the mode of action of cardiovascular drugs. Adv Prostaglandin Thromboxane Res. 1980;7:609–618. [PubMed] [Google Scholar]
- Ganz W., Marcus H. S. Failure of intracoronary nitroglycerin to alleviate pacing-induced angina. Circulation. 1972 Nov;46(5):880–889. doi: 10.1161/01.cir.46.5.880. [DOI] [PubMed] [Google Scholar]
- Hampton J. R., Harrison M. J., Honour A. J., Mitchell J. R. Platelet behaviour and drugs used in cardiovascular disease. Cardiovasc Res. 1967 Apr;1(2):101–107. doi: 10.1093/cvr/1.2.101. [DOI] [PubMed] [Google Scholar]
- Harder D. R., Belardinelli L., Sperelakis N., Rubio R., Berne R. M. Differential effects of adenosine and nitroglycerin on the action potentials of large and small coronary arteries. Circ Res. 1979 Feb;44(2):176–182. doi: 10.1161/01.res.44.2.176. [DOI] [PubMed] [Google Scholar]
- Haslam R. J., Rosson G. M. Effects of adenosine on levels of adenosine cyclic 3',5'-monophosphate in human blood platelets in relation to adenosine incorporation and platelet aggregation. Mol Pharmacol. 1975 Sep;11(5):528–544. [PubMed] [Google Scholar]
- Hood W. P., Jr, Amende I., Simon R., Lichtlen P. R. The effects of intracoronary nitroglycerin on left ventricular systolic and diastolic function in man. Circulation. 1980 Jun;61(6):1098–1104. doi: 10.1161/01.cir.61.6.1098. [DOI] [PubMed] [Google Scholar]
- Jaffe E. A., Mosher D. F. Synthesis of fibronectin by cultured human endothelial cells. J Exp Med. 1978 Jun 1;147(6):1779–1791. doi: 10.1084/jem.147.6.1779. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jaffe E. A., Nachman R. L., Becker C. G., Minick C. R. Culture of human endothelial cells derived from umbilical veins. Identification by morphologic and immunologic criteria. J Clin Invest. 1973 Nov;52(11):2745–2756. doi: 10.1172/JCI107470. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jaffe E. A., Weksler B. B. Recovery of endothelial cell prostacyclin production after inhibition by low doses of aspirin. J Clin Invest. 1979 Mar;63(3):532–535. doi: 10.1172/JCI109332. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Katsuki S., Arnold W. P., Murad F. Effects of sodium nitroprusside, nitroglycerin, and sodium azide on levels of cyclic nucleotides and mechanical activity of various tissues. J Cyclic Nucleotide Res. 1977 Aug;3(4):239–247. [PubMed] [Google Scholar]
- Kukovetz W. R., Holzmann S., Wurm A., Pöch G. Prostacyclin increases cAMP in coronary arteries. J Cyclic Nucleotide Res. 1979 Dec;5(6):469–476. [PubMed] [Google Scholar]
- Marcus A. J., Weksler B. B., Jaffe E. A., Broekman M. J. Synthesis of prostacyclin from platelet-derived endoperoxides by cultured human endothelial cells. J Clin Invest. 1980 Nov;66(5):979–986. doi: 10.1172/JCI109967. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Marcus A. J., Weksler B. B., Jaffe E. A. Enzymatic conversion of prostaglandin endoperoxide H2 and arachidonic acid to prostacyclin by cultured human endothelial cells. J Biol Chem. 1978 Oct 25;253(20):7138–7141. [PubMed] [Google Scholar]
- Moncada S., Needleman P., Bunting S., Vane J. R. Prostaglandin endoperoxide and thromboxane generating systems and their selective inhibition. Prostaglandins. 1976 Sep;12(3):323–335. doi: 10.1016/0090-6980(76)90014-9. [DOI] [PubMed] [Google Scholar]
- Moncada S., Vane J. R. Unstable metabolites of arachidonic acid and their role in haemostasis and thrombosis. Br Med Bull. 1978 May;34(2):129–135. doi: 10.1093/oxfordjournals.bmb.a071482. [DOI] [PubMed] [Google Scholar]
- Morcillio E., Reid P. R., Dubin N., Ghodgaonkar R., Pitt B. Myocardial prostaglandin E release by nitroglycerin and modification by indomethacin. Am J Cardiol. 1980 Jan;45(1):53–57. doi: 10.1016/0002-9149(80)90219-2. [DOI] [PubMed] [Google Scholar]
- Neichi T., Tomisawa S., Kubodera N., Uchida Y. Enhancement of PGI2 formation by a new vasodilator, 2-nicotinamidoethyl nitrate in the coupled system of platelets and aortic microsomes. Prostaglandins. 1980 Apr;19(4):577–586. doi: 10.1016/s0090-6980(80)80007-4. [DOI] [PubMed] [Google Scholar]
- Oliva P. B., Breckinridge J. C. Arteriographic evidence of coronary arterial spasm in acute myocardial infarction. Circulation. 1977 Sep;56(3):366–374. doi: 10.1161/01.cir.56.3.366. [DOI] [PubMed] [Google Scholar]
- Pearson J. D., Gordon J. L. Vascular endothelial and smooth muscle cells in culture selectively release adenine nucleotides. Nature. 1979 Oct 4;281(5730):384–386. doi: 10.1038/281384a0. [DOI] [PubMed] [Google Scholar]
- Saxon A., Kattlove H. E. Platelet inhibition by sodium nitroprusside, a smooth muscle inhibitor. Blood. 1976 Jun;47(6):957–961. [PubMed] [Google Scholar]
- Schafer A. I., Alexander R. W., Handin R. I. Inhibition of platelet function by organic nitrate vasodilators. Blood. 1980 Apr;55(4):649–654. [PubMed] [Google Scholar]
- Sturek J. K., Sokoloski T. D., Winsley W. T., Stach P. E. Stability of nitroglycerin injection determined by gas chromatography. Am J Hosp Pharm. 1978 May;35(5):537–541. [PubMed] [Google Scholar]
- Swain J. L., Parker J. P., McHale P. A., Greenfield J. C., Jr Effects of nitroglycerin and propranolol on the distribution of transmural myocardial blood flow during ischemia in the absence of hemodynamic changes in the unanesthetized dog. J Clin Invest. 1979 May;63(5):947–953. doi: 10.1172/JCI109395. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Synek P., Rysánek K., Spánková H., Mlejnková M. The effect of ethanol and nitroglycerin on platelet aggregation. Act Nerv Super (Praha) 1970 Jan 12;12(1):77–78. [PubMed] [Google Scholar]
- Vatner S. F., Higgins C. B., Milland R. W., Franklin D. Direct and reflex effects of nitroglycerin on coronary and left ventricular dynamics in conscious dogs. J Clin Invest. 1972 Nov;51(11):2872–2882. doi: 10.1172/JCI107110. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wei J. Y., Reid P. R. Quantitative determination of trinitroglycerin in human plasma. Circulation. 1979 Mar;59(3):588–592. doi: 10.1161/01.cir.59.3.588. [DOI] [PubMed] [Google Scholar]
- Weksler B. B., Gillick M., Pink J. Effect of propranolol on platelet function. Blood. 1977 Feb;49(2):185–196. [PubMed] [Google Scholar]
- Weksler B. B., Marcus A. J., Jaffe E. A. Synthesis of prostaglandin I2 (prostacyclin) by cultured human and bovine endothelial cells. Proc Natl Acad Sci U S A. 1977 Sep;74(9):3922–3926. doi: 10.1073/pnas.74.9.3922. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wong P. Y., Lee W. H., Chao P. H., Reiss R. F., McGiff J. C. Metabolism of prostacyclin by 9-hydroxyprostaglandin dehydrogenase in human platelets. Formation of a potent inhibitor of platelet aggregation and enzyme purification. J Biol Chem. 1980 Oct 10;255(19):9021–9024. [PubMed] [Google Scholar]
- Wong P. Y., McGiff J. C., Sun F. F., Lee W. H. 6-Keto-prostaglandin E1 inhibits the aggregation of human platelets. Eur J Pharmacol. 1979 Dec 7;60(2-3):245–248. doi: 10.1016/0014-2999(79)90225-5. [DOI] [PubMed] [Google Scholar]