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Characterization of [ 3 H]Quipazine Binding to 5‐Hydroxytryptamine 3 Receptors in Rat Brain Membranes
Author(s) -
Milburn Christina M.,
Peroutka Stephen J.
Publication year - 1989
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.1471-4159.1989.tb07258.x
Subject(s) - quipazine , receptor , radioligand , binding site , 5 ht receptor , stereochemistry , population , serotonin , radioligand assay , guanine , chemistry , membrane , biology , biochemistry , biophysics , nucleotide , medicine , environmental health , gene
[ 3 H]Quipazine was used to label binding sites in rat brain membranes that display characteristics of a 5‐hydroxytryptamine 3 (5‐HT 3 ) receptor. The radioligand binds with high affinity ( K D , 1.2 ± 0.1 n M ) to a saturable population of sites ( B max , 3.0 ± 0.4 pmol/g of tissue) that are differentially located in the brain. Specific [ 3 H]quipazine binding is not affected by guanine or adenine nucleotides. ICS 205–930, BRL 43964, Lilly 278584, and zacopride display less than nanomolar affinity for these sites whereas MDL 72222 is approximately one order of magnitude less potent. The pharmacological profile of the binding site is in excellent agreement with that of 5‐HT 3 receptors characterized in peripheral physiological models. We conclude that [ 3 H]quipazine labels a 5‐HT 3 receptor in the rat CNS.