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THE BINDING OF [ 3 H]‐PROSTACYCLIN TO MEMBRANES OF A NEURONAL SOMATIC HYBRID
Author(s) -
BLAIR I.A.,
MACDERMOT J.
Publication year - 1981
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1981.tb10994.x
Subject(s) - prostacyclin , dissociation constant , receptor , dissociation (chemistry) , reaction rate constant , chemistry , population , ligand (biochemistry) , biophysics , membrane , binding site , prostaglandin , stereochemistry , biochemistry , kinetics , biology , physics , quantum mechanics , demography , sociology
1 [ 3 H]‐prostacylin bound to a washed membrane preparation of the NCB‐20 neuronal hybrid cell line. 2 Kinetic analysis of [ 3 H]‐prostacyclin binding suggested a simple, non‐cooperative bimolecular interaction between the ligand and a single receptor population. The equilibrium dissociation constant was 16.6 n m , and binding at a saturating [ 3 H]‐prostacyclin concentration enabled the receptor density of 2.57 × 10 5 receptor molecules per cell to be calculated. 3 At 20°C the rate constant for the forward reaction ( k +1 ) was 2.26 × 10 5 m −1 s −1 , and the rate constant for the dissociation of the ligand‐receptor complex ( k ‐1 ) was 3.85 × 10 −3 s −1 . Thus the dissociation constant ( k ‐1 / k +1 ) was 17.0 n m . 4 Prostaglandin E 1 and prostacyclin compete for a single receptor in these cells, and comparison of other prostaglandins as inhibitors of [ 3 H]‐prostacyclin binding revealed some of the structural requirements for high‐affinity occupation of prostacyclin receptors.