Characterization of the binding sites of [3H]SR 48968, a potent nonpeptide radioligand antagonist of the neurokinin-2 receptor

• Published in: Biochemical and biophysical research communications Vol. 191; no. 3; p. 1172
• Main Authors: Emonds-Alt, X, Golliot, F, Pointeau, P, Le Fur, G, Breliere, J C
• Format: Journal Article
• Language: English
• Published: United States 31-03-1993
• Subjects: Animals; Benzamides - metabolism; Binding Sites; Binding, Competitive; Cricetinae; Duodenum - metabolism; Guinea Pigs; In Vitro Techniques; Kinetics; Mesocricetus; Piperidines - metabolism; Rats; Rats, Sprague-Dawley; Receptors, Neurokinin-2; Receptors, Neurotransmitter - antagonists & inhibitors; Receptors, Neurotransmitter - metabolism; Substance P - antagonists & inhibitors; Urinary Bladder - metabolism
• ISSN: 0006-291X
• DOI: 10.1006/bbrc.1993.1340

[3H]SR 48968, a radiolabeled nonpeptide antagonist of NK-2 receptor, has been tested in ligand-receptor binding assays using rat duodenum, hamster urinary bladder and guinea pig ileum membranes. [3H]SR 48968 bound to a single class of high affinity binding sites. Its affinity was slightly species-dependent. Its binding was inhibited by neurokinins, following the rank order of potency NKA > NKB > SP. It was also inhibited by peptide antagonists of NK-2 receptor (MEN 10,376, L 659,877), but their relative potencies were highly species-dependent. Unlabeled SR 48968, but not its R-enantiomer (SR 48965), also potently inhibited its binding. These data show that [3H]SR 48968 potently binds to NK-2 receptor and therefore is a useful tool to study NK-2 receptor.