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Stable expression of high affinity NK 1 (substance P) and NK 2 (neurokinin A) receptors but low affinity NK 3 (neurokinin B) receptors in transfected CHO cells
Author(s) -
Gether Ulrik,
Marray Taisser,
Schwartz Thue W.,
Johansen Teit E.
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80295-r
Subject(s) - receptor , tachykinin receptor , neurokinin b , chinese hamster ovary cell , neurokinin a , transfection , microbiology and biotechnology , biology , chemistry , substance p , biochemistry , neuropeptide , gene
Stable CHO cell clones which selectively express all three rat tachykinin receptors were established by transfection. The binding of radiolabeled substance P and neurokinin A (substance K) to CHO clones expressing the NK 1 and NK 2 receptors, respectively, were saturatable and of high affinity ( K d 1=0.17 nM (NK 1 ); 3.4 nM (NK 2 )). Scatchard analysis of the binding data indicated for both receptors binding to a single population of binding sites, and competition binding studies showed that the binding specificities of the receptors corresponded to those of classical NK 1 and NK 2 receptors. In contrast, the binding of eledoisin to the NK 3 receptor expressed in the transfected CHO cells was of low affinity (IC 50 =240 nM) compared to the high affinity of the receptor found when it was transiently expressed in COS‐7 cells (IC 50 =8 nM). However, in both cases the receptor exhibited the specificity of a classical NK 3 receptor. The established cell clones may provide an important tool for further analysis of the molecular mechanisms involved in binding, activation, and coupling of receptors for tachykinin peptides.