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High‐ and Low‐Affinity Binding of [ 3 H]Imipramine in Rat Hypothalamus
Author(s) -
Moret C.,
Briley M.
Publication year - 1986
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.1471-4159.1986.tb00802.x
Subject(s) - imipramine , tricyclic , tricyclic antidepressant , sodium , chemistry , hypothalamus , binding site , serotonin , endocrinology , medicine , pharmacology , antidepressant , stereochemistry , receptor , biology , biochemistry , hippocampus , organic chemistry , alternative medicine , pathology
In the rat hypothalamus [ 3 H]imipramine binding is inhibited by tricyclic and nontricyclic antidepressant drugs in a complex manner, with biphasic curves and Hill coefficients <1.0. 5‐Hydroxytryptamine (serotonin) inhibited with high affinity a decreasing proportion of the [ 3 H]‐imipramine binding sites as the [ 3 H]imipramine concentration was raised. In the absence of sodium ions, IC 50 values for the inhibition by tricyclic and nontricyclic antidepressants were increased by approximately 1,000‐fold, and the inhibition curves became classically monophasic with Hill coefficients close to 1.0. These data are interpreted as suggesting that [ 3 H]imipramine binds to two independent sites in the rat hypothalamus. One site is sodium‐dependent with a high affinity for the drugs tested; the other is sodium‐independent and has a low affinity for these drugs.