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Binding of [ 3 H]SKF 38393 to Dopamine D‐l Receptors in Rat Striatum In Vitro; Estimation of Receptor Molecular Size by Radiation Inactivation
Author(s) -
Gredal Ole,
Nielsen Mogens
Publication year - 1987
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1987.tb04103.x
Subject(s) - striatum , dopamine , agonist , dopamine receptor , receptor , chemistry , antagonist , d 1 , binding site , sch 23390 , dopamine agonist , dopamine antagonist , in vitro , pharmacology , biochemistry , endocrinology , biology
[ 3 H]SKF 38393 (2,3,4,5,‐tetrahydro‐7,8‐dihy‐droxy‐l‐phenyl‐l H ‐3‐benzazepine) binds with high affinity to 3,4‐dihydroxyphenylethylamine (dopamine) D‐l receptors in rat striatum in vitro ( K D = 7 and 14 n M in nonfrozen and frozen striatum, respectively). The number of binding sites (5 max ) was ∼ 80.0 pmol/g of original tissue, a value similar to the B max for the dopamine D‐l antagonist SCH 23390. Nondisplaceable [ 3 H]SKF 38393 binding was ∼45% of total binding. Irradiation (0–4 Mrad) of frozen whole striata decreased the number of [ 3 H]SKF 38393 binding sites monoexponentially without changing the binding affinity. The functional molecular mass for the agonist dopamine D‐1 binding site was 132,800 daltons, which is higher than the functional molecular mass of the antagonist dopamine D‐1 binding site (∼80,000 daltons).