Characterization of [3H]substance P binding sites in human skin.
Radioligand binding experiments were performed with crude homogenates from normal human skin in order to investigate substance P receptor density. Binding of [3H]substance P ([3H]SP) reached equilibrium after 20 min and was saturable analysis of saturation curves gave a significantly better fit using two-site binding compared to the single-site model. Competition studies employing some selective agonists for NK1, NK2 and NK3 receptors have demonstrated that only the NK1 selective agonist, [Sar9, Met(O2)11]-SP, was a competitor for [3H]SP binding. In addition, the non-hydrolyzable guanosine 5'-0-(3-thiotriphosphate) altered the dissociation of SP from NK1 receptors by increasing the number of low-affinity sites. These data show that in the skin [3H]SP binds to a single population of substance P high-affinity sites, which represent NK1-type receptors.
Bianchi
B
B
Institute of Dermatology and Venereology, University of Florence, Italy.
Matucci
R
R
Danesi
A
A
Rossi
R
R
Ipponi
P
P
Giannotti
B
B
Johansson
O
O
Cappugi
P
P
D000368:Aged; D001667:Binding, Competitive / Q000187:drug effects; D005260:Female; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015288:Neurokinin A / Q000031:analogs & derivatives / Q000494:pharmacology; D015287:Neurokinin B / Q000031:analogs & derivatives / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D011869:Radioligand Assay; D018040:Receptors, Neurokinin-1 / Q000819:agonists / Q000378:metabolism; D018041:Receptors, Neurokinin-2 / Q000819:agonists; D018042:Receptors, Neurokinin-3 / Q000819:agonists; D012867:Skin / Q000187:drug effects / Q000378:metabolism*; D013373:Substance P / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D014316:Tritium
D010446:Peptide Fragments; D018040:Receptors, Neurokinin-1; D018041:Receptors, Neurokinin-2; D018042:Receptors, Neurokinin-3; C080394:neurokinin B, MePhe(7)-; D014316:Tritium; C062618:substance P, Sar(9)-Met(O2)(11)-; C069192:neurokinin A(4-10), Tyr(5)-Trp(6,8,9)-Lys(10)-; D013373:Substance P; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D015288:Neurokinin A; D015287:Neurokinin B