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Ligand Binding Kinetics of Substance P and Neurokinin A Receptors Stably Expressed in Chinese Hamster Ovary Cells and Evidence for Differential Stimulation of Inositol 1,4,5‐Trisphosphate and Cyclic AMP Second Messenger Responses
Author(s) -
Takeda Yasuo,
Blount Paul,
Sachais Bruce S.,
Hershey Andrew D.,
Raddatz Rita,
Krause James E.
Publication year - 1992
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.1471-4159.1992.tb09430.x
Subject(s) - chinese hamster ovary cell , receptor , neurokinin b , ligand (biochemistry) , biology , neurokinin a , inositol phosphate , agonist , substance p , stimulation , tachykinin receptor 1 , second messenger system , chemistry , endocrinology , inositol , medicine , microbiology and biotechnology , biochemistry , neuropeptide
Stably transfected Chinese hamster ovary cells expressing either the substance P receptor or neurokinin A receptor were constructed, isolated, and characterized. Equilibrium ligand binding studies performed on whole cells demonstrated that cell lines expressing either of these receptors contained a single class of high‐affinity binding sites with an apparent K D of 0.16 n M for the substance P receptor and an apparent K D of 2.1 n M for the neurokinin A receptor. The higher affinity of substance P for its receptor was accounted for by both a greater association rate constant and a lesser dissociation rate constant. The time course and extent of ligand‐stimulated inositol 1,4,5‐trisphosphate mass increases in both cell lines were similar and displayed rapid and transient kinetics. Ligand‐stimulated cyclic AMP accumulation was also apparent in the cell lines, although the time course and magnitude of the responses were substantially different, with the neurokinin A receptor mediating a greater and more prolonged response. These studies establish the presence of functional substance P receptors and neurokinin A receptors in the stably transfected cell lines and provide evidence for agonist‐dependent differential stimulation of second messenger responses.