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. 1982 Jul;70(1):209–212. doi: 10.1172/JCI110596

Binding of a Calcium Antagonist, [3H]Nitrendipine, to High Affinity Sites in Bovine Aortic Smooth Muscle and Canine Cardiac Membranes

Lewis T Williams 1,2, Patrice Tremble 1,2
PMCID: PMC370245  PMID: 6282938

Abstract

[3H]Nitrendipine, a potent calcium channel antagonist [3-ethyl-5-methyl-1-1,4-dihydro-2,6 - dimethyl - 4 - (3 - nitrophenyl) - 3,5 - pyridine carboxylate], was used to label high affinity binding sites on membranes prepared from bovine aortic smooth muscle. The binding of [3H]nitrendipine is rapid (t1/2 < 5 min) and reversible at 37°C. The binding sites have a high affinity for [3H]nitrendipine with an equilibrium dissociation constant of 2.1 nM. The density of sites is 40-60 fmol/mg of membrane protein. Analogues of nitrendipine compete for the binding sites with affinities consistent with their known biological effects as calcium antagonists. Nisoldipine, [isobutyl methyl 1,4-dihydro-2,6-dimethyl-4-(2-nitrophenyl)-3,5-pyridine carboxylate], a calcium antagonist more potent than nifedipine [2,6-dimethyl-3,5-dicarbomethoxy-4-(2-nitrophenyl)-1,4-dihydropyridine] in relaxing vascular smooth muscle, has an affinity three-fold higher than that of nifedipine in competing for the binding sites. A biologically inactive derivative of nifedipine does not compete for [3H]nitrendipine binding. Verapamil (α-isopropyl-α[(N-methyl - N-homoveratryl) -α-aminopropyl]-3,4-dimethyoxyphenyl acetonitrile), a structurally different calcium antagonist, only partially (25%) inhibits binding at high concentrations (1 μM). Prazosin, an alpha adrenergic antagonist does not compete for [3H]nitrendipine binding sites. The binding of [3H]nitrendipine is not affected by 1.5 mM calcium. Canine cardiac membranes also have high affinity [3H]nitrendipine binding sites, (KD = 6 nM) but bovine erythrocytes do not. The relative affinities of nisoldipine and nifedipine for the cardiac membrane binding sites reflect the relative activities of these compounds as calcium channel antagonists. These results suggest that the [3H]nitrendipine binding sites are the sites through which dihydropyridines act as calcium channel antagonists.

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Selected References

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  1. Bolger G. T., Gengo P. J., Luchowski E. M., Siegel H., Triggle D. J., Janis R. A. High affinity binding of a calcium channel antagonist to smooth and cardiac muscle. Biochem Biophys Res Commun. 1982 Feb 26;104(4):1604–1609. doi: 10.1016/0006-291x(82)91436-x. [DOI] [PubMed] [Google Scholar]
  2. Catterall W. A. Neurotoxins that act on voltage-sensitive sodium channels in excitable membranes. Annu Rev Pharmacol Toxicol. 1980;20:15–43. doi: 10.1146/annurev.pa.20.040180.000311. [DOI] [PubMed] [Google Scholar]
  3. Dangman K. H., Hoffman B. F. Effects of nifedipine on electrical activity of cardiac cells. Am J Cardiol. 1980 Dec 1;46(6):1059–1067. doi: 10.1016/0002-9149(80)90367-7. [DOI] [PubMed] [Google Scholar]
  4. Fleckenstein A. Specific pharmacology of calcium in myocardium, cardiac pacemakers, and vascular smooth muscle. Annu Rev Pharmacol Toxicol. 1977;17:149–166. doi: 10.1146/annurev.pa.17.040177.001053. [DOI] [PubMed] [Google Scholar]
  5. Henry P. D. Comparative pharmacology of calcium antagonists: nifedipine, verapamil and diltiazem. Am J Cardiol. 1980 Dec 1;46(6):1047–1058. doi: 10.1016/0002-9149(80)90366-5. [DOI] [PubMed] [Google Scholar]
  6. Kazda S., Garthoff B., Meyer H., Schlossmann K., Stoepel K., Towart R., Vater W., Wehinger E. Pharmacology of a new calcium antagonistic compound, isobutyl methyl 1,4-dihydro-2,6-dimethyl-4(2-nitrophenyl)-3,5-pyridinedicarboxylate (Nisoldipine, Bay k 5552). Arzneimittelforschung. 1980;30(12):2144–2162. [PubMed] [Google Scholar]
  7. Kohlhardt M., Fleckenstein A. Inhibition of the slow inward current by nifedipine in mammalian ventricular myocardium. Naunyn Schmiedebergs Arch Pharmacol. 1977 Jul;298(3):267–272. doi: 10.1007/BF00500899. [DOI] [PubMed] [Google Scholar]
  8. Meyer H., Bossert F., Wehinger E., Stoepel K., Vater W. Synthese und vergleichende pharmakologische Untersuchungen von 1,4-Dihydro-2,6-dimethyl-4-(3-nitrophenyl)pyridin-3,5-dicarbonsäureestern mit nicht-identischen Esterfunktionen. Arzneimittelforschung. 1981;31(3):407–409. [PubMed] [Google Scholar]
  9. Murphy K. M., Snyder S. H. Calcium antagonist receptor binding sites labeled with [3H]nitrendipine. Eur J Pharmacol. 1982 Jan 22;77(2-3):201–202. doi: 10.1016/0014-2999(82)90021-8. [DOI] [PubMed] [Google Scholar]
  10. Rosenberger L. B., Ticku M. K., Triggle D. J. The effect of Ca2+ antagonists on mechanical responses and Ca2+ movements in guinea pig ileal longitudinal smooth muscle. Can J Physiol Pharmacol. 1979 Apr;57(4):333–347. doi: 10.1139/y79-052. [DOI] [PubMed] [Google Scholar]
  11. Stone P. H., Antman E. M., Muller J. E., Braunwald E. Calcium channel blocking agents in the treatment of cardiovascular disorders. Part II: Hemodynamic effects and clinical applications. Ann Intern Med. 1980 Dec;93(6):886–904. doi: 10.7326/0003-4819-93-6-886. [DOI] [PubMed] [Google Scholar]
  12. Towart R. The selective inhibition of serotonin-induced contractions of rabbit cerebral vascular smooth muscle by calcium-antagonistic dihydropyridines. An investigation of the mechanism of action of nimodipine. Circ Res. 1981 May;48(5):650–657. doi: 10.1161/01.res.48.5.650. [DOI] [PubMed] [Google Scholar]

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