Characterization of the binding of [125I-iodo-histidyl, methyl-Phe7] neurokinin B to the neurokinin-3 receptor.
We have characterized the binding of [125I-iodo-histidyl, methyl Phe7]neurokinin B (125I-NKB) to the human neurokinin-3 (NK3) receptor. 125I-NKB specifically binds to the NK3 receptor expressed in CHO cells with a Kd of 0.2 nM. The ligand displays little crossreactivity with the human NK1 and NK2 receptors. The binding of 125I-NKB to the human NK3 receptor and to rat cortex membranes is inhibited by neurokinin B with IC50 of 1.5 nM and 4 nM, respectively. In contrast, 350- to 500-fold higher concentrations of substance P and neurokinin A are required to inhibit binding to either receptor preparation. The data suggest that 125I-NKB is a high affinity, selective ligand for the human and rat NK3 receptor.
Sadowski
S
S
Department of Molecular Pharmacology and Biochemistry, Merck Research Laboratories, Rahway, NJ 07065.
Huang
R R
RR
Fong
T M
TM
Marko
O
O
Cascieri
M A
MA
D000818:Animals; D016466:CHO Cells / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism; D006224:Cricetinae; D006801:Humans; D015288:Neurokinin A / Q000494:pharmacology; D015287:Neurokinin B / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D018041:Receptors, Neurokinin-2; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013373:Substance P / Q000494:pharmacology
D018041:Receptors, Neurokinin-2; D017981:Receptors, Neurotransmitter; D011994:Recombinant Proteins; C082567:neurokinin B, I-His-MePhe(7)-; D013373:Substance P; D015288:Neurokinin A; D015287:Neurokinin B