Different Subtypes of Tachykinin NK₁ Receptor Binding Sites Are Present in the Rat Brain

Effects of Substance P in the Amygdala, Ventromedial Hypothalamus, and Periaqueductal Gray on Fear-Potentiated Startle

“…However, in the hypothalamus, the primary SP receptors are the non-septide-sensitive SP receptors to which GR 82334 has a lower affinity (Beaujouan et al, 2000). Therefore, a higher dose of GR 82334 may be required to block SP neurotransmisson in the VMH.…”

Neurokinin A engages neurokinin-1 receptor to induce NF-κB-dependent gene expression in murine macrophages: implications of ERK1/2 and PI 3-kinase/Akt pathways

“…However, a number of studies show that NKA is also a functional ligand for the NK-1 receptor in vivo and in vitro (1,5,8,17,45). NKA is a high-affinity ligand for the NK-1 receptors expressed in transfected cell lines, despite its weak ability to displace SP-NK-1 receptor binding (17).…”

Involvement of the Second Extracellular Loop (E2) of the Neurokinin-1 Receptor in the Binding of Substance P

“…4 for a review). Binding experiments with SP analogs in tissues and in cells transfected with the NK-1 receptor have shown that two types of non-stoichiometric binding sites with distinct pharmacological profiles are associated with the NK-1 receptor (5)(6)(7)(8)(9)(10)(11)(12). In CHO cells, B max values for the two binding sites were found to be 6000 fmol/mg proteins and 800 fmol/mg proteins for the major binding site ( 11 ]SP-(7-11), respectively (7).…”

“…In the CHO clone used herein, the more and less abundant binding sites represent 85 and 15% of the total population of receptors (6 pmol/mg of proteins), respectively (7). Substance P binds the two binding sites with high affinity, whereas some C-terminal fragment analogs of substance P and some substance P-(1-11) analogs, as well as the endogenous tachykinin NK-2 ligand neurokinin A, bind only the less abundant one (7)(8)(9)(10)(11)(12). Although several structure-activity relationship studies have been carried out, little is known about the differences in the molecular recognition of these two binding sites (8 -12).…”

“…Both photoactivatable SP analogs, [BAPA-Lys 6 ,(p-Bz)Phe 8 ,Pro 9 ,-Met (O 2 ) 11 ]SP- (7)(8)(9)(10)(11) and [BAPA 0 ,(p-Bz)Phe 8 ]SP, contain a biotinyl sulfone moiety at the N-terminal end, which is separated from the first amino acid by an aminopentanoic acid flexible spacer (BAPA). After photolabeling and enzymatic digestion(s), this biotinyl sulfone moiety is used to purify the fragment of interest via streptavidin-coated magnetic beads (14,15).…”