Bradykinin antagonists in human systems: Correlation between receptor binding, calcium signalling in isolated cells, and functional activity in isolated ileum

• Published in: Biochemical pharmacology Vol. 54; no. 2; pp. 283 - 291
• Main Authors: Wieczorek, Maciej, Pilyavskaya, Anna, Burkard, Michael, Zuzack, John S., Jones, Steven W., Francis, Mary D., Beckey, Virginia E., Ross, Sherman E., Goodfellow, Val S., Fitzpatrick, Timothy D., Marathe, Manoj V., Gyorkos, Albert, Spruce, Lyle W., Selig, William M., Stewart, John M., Gera, Lajos, Whalley, Eric T.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 15.07.1997; Elsevier Science
• Subjects: B 2 receptor; Biological and medical sciences; Bradykinin - antagonists & inhibitors; bradykinin antagonists; Calcium - metabolism; calcium flux; Dihydromorphine - pharmacology; human ileum; Humans; Ileum - metabolism; Ileum - physiology; In Vitro Techniques; Medical sciences; Neuropharmacology; Neurotransmitters. Neurotransmission. Receptors; Peptidergic system (neuropeptide, opioid peptide, opiates...). Adenosinergic and purinergic systems; Pharmacology. Drug treatments; Receptors, Bradykinin - metabolism; Signal Transduction; B 2, bradykinin 2 receptor; TES; mR; membane-bound receptor; bradykinin antagonists; calcium flux; BK; piperazine- N, N″-bis[2-ethanesulfonic acid]; Eagle's Minimum Essential Medium; PIPES; bradykinin, CHAPS, 3-[(-cholamidopropyl)dimethylammonio]-1-propane-sulfonate; pX, sR, soluble receptor; B 2 receptor; EMEM; fetal bovine serum; human ileum; FBS; N-tris[hydroxymethyl]methyl-2-aminoethanesulfonic acid; PCR; polymerase chain reaction; Human; Digestive system; Gut; Ion transport; Calcium Ions; Ileum; In vitro; Contraction; Biological fixation; Bradykinin; Peptidergic receptor; Antagonist; Inhibition; Fibroblast
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/S0006-2952(97)00186-X

The determination of the relationship between ligand affinity and bioactivity is important for the understanding of receptor function in biological systems and for drug development. Several physiological and pathophysiological functions of bradykinin (BK) are mediated via the B 2 receptor. In this study, we have examined the relationship between B 2 receptor (soluble and membrane-bound) binding of BK peptidic antagonists, inhibition of calcium signalling at a cellular level, and in vitro inhibition of ileum contraction. Only human systems were employed in the experiments. Good correlations between the studied activities of BK antagonists were observed for a variety of different peptidic structures. The correlation coefficients (r) were in the range of 0.905 to 0.955. In addition, we analyzed the effect of the C-terminal Arg 9 removal from BK and its analogs on E 2 receptor binding. The ratios of binding constants ( K i +Arg K i −Arg ) for the Arg 9 containing compounds and the corresponding des-Arg 9 analogs varied from about 10 to 250,000. These ratios strongly depend on the chemical structures of the compounds. The highest ratios were observed for two natural agonist pairs, BK/des-Arg 9-BK and Lys°-BK/des-Arg 9-Lys°-BK.