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125I-Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK, a radiolabelled B2 antagonist specifically interacts with two distinct binding sites on epithelial membranes of guinea pig ileum.
Agents Actions Suppl. 1992; 38 (Pt 1):526-39.AA

Abstract

Kinins are endogenously formed peptides that have diverse biological actions, including effects on the gastrointestinal tract. In the search of selective ligands, we studied the binding properties of a selective B2 radioiodinated antagonist (Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK) on epithelial membranes of guinea pig ileum. Equilibrium binding experiments showed that 125I-Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK specifically labels two different sites. One of these sites is the conventional B2 receptor. The new tracer recognized this site with a Kd of 34.7 nM and revealed a Bmax of 156 fmol/mg protein. In equilibrium binding experiments 125I-Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK also recognized a second specific site. Scatchard analysis showed that this second site was of high affinity (Kd of 16.8 nM) and very abundant (Bmax of 2.08 pmol/mg protein). Surprisingly, the natural B2 agonists bradykinin and kallidin were unable to inhibit the specific binding of 125I-Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK to the second site. A series of B2 antagonists failed to inhibit the specific binding of the new radiolabelled peptide. As expected, non related peptides such as angiotensin II, neurokinin A and B, substance P, vasopressin, calcitonin gene related peptide and bombesin were also inactive. These results show that the new tracer is interacting with two distinct binding sites in epithelial membranes of guinea pig ileum. One is the well known bradykinin B2 receptor and the other is a new, non characterized binding site that interacts exclusively with bradykinin receptor antagonists.

Authors+Show Affiliations

Department of Pharmacology, Medical School, University of Sherbrooke, Québec, Canada.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

1334630

Citation

Tousignant, C, et al. "125I-Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK, a Radiolabelled B2 Antagonist Specifically Interacts With Two Distinct Binding Sites On Epithelial Membranes of Guinea Pig Ileum." Agents and Actions. Supplements, vol. 38 (Pt 1), 1992, pp. 526-39.
Tousignant C, Regoli D, Rhaleb NE, et al. 125I-Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK, a radiolabelled B2 antagonist specifically interacts with two distinct binding sites on epithelial membranes of guinea pig ileum. Agents Actions Suppl. 1992;38 (Pt 1):526-39.
Tousignant, C., Regoli, D., Rhaleb, N. E., Jukic, D., & Guillemette, G. (1992). 125I-Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK, a radiolabelled B2 antagonist specifically interacts with two distinct binding sites on epithelial membranes of guinea pig ileum. Agents and Actions. Supplements, 38 (Pt 1), 526-39.
Tousignant C, et al. 125I-Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK, a Radiolabelled B2 Antagonist Specifically Interacts With Two Distinct Binding Sites On Epithelial Membranes of Guinea Pig Ileum. Agents Actions Suppl. 1992;38 (Pt 1):526-39. PubMed PMID: 1334630.
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TY - JOUR T1 - 125I-Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK, a radiolabelled B2 antagonist specifically interacts with two distinct binding sites on epithelial membranes of guinea pig ileum. AU - Tousignant,C, AU - Regoli,D, AU - Rhaleb,N E, AU - Jukic,D, AU - Guillemette,G, PY - 1992/1/1/pubmed PY - 1992/1/1/medline PY - 1992/1/1/entrez SP - 526 EP - 39 JF - Agents and actions. Supplements JO - Agents Actions Suppl VL - 38 (Pt 1) N2 - Kinins are endogenously formed peptides that have diverse biological actions, including effects on the gastrointestinal tract. In the search of selective ligands, we studied the binding properties of a selective B2 radioiodinated antagonist (Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK) on epithelial membranes of guinea pig ileum. Equilibrium binding experiments showed that 125I-Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK specifically labels two different sites. One of these sites is the conventional B2 receptor. The new tracer recognized this site with a Kd of 34.7 nM and revealed a Bmax of 156 fmol/mg protein. In equilibrium binding experiments 125I-Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK also recognized a second specific site. Scatchard analysis showed that this second site was of high affinity (Kd of 16.8 nM) and very abundant (Bmax of 2.08 pmol/mg protein). Surprisingly, the natural B2 agonists bradykinin and kallidin were unable to inhibit the specific binding of 125I-Tyr,D-Arg[Hyp3,D-Phe7,Leu8]BK to the second site. A series of B2 antagonists failed to inhibit the specific binding of the new radiolabelled peptide. As expected, non related peptides such as angiotensin II, neurokinin A and B, substance P, vasopressin, calcitonin gene related peptide and bombesin were also inactive. These results show that the new tracer is interacting with two distinct binding sites in epithelial membranes of guinea pig ileum. One is the well known bradykinin B2 receptor and the other is a new, non characterized binding site that interacts exclusively with bradykinin receptor antagonists. SN - 0379-0363 UR - https://www.unboundmedicine.com/medline/citation/1334630/125I_TyrD_Arg[Hyp3D_Phe7Leu8]BK_a_radiolabelled_B2_antagonist_specifically_interacts_with_two_distinct_binding_sites_on_epithelial_membranes_of_guinea_pig_ileum_ L2 - https://antibodies.cancer.gov/detail/CPTC-HLA-B-1 DB - PRIME DP - Unbound Medicine ER -