title: The influence of affinity, efficacy, and slope factor on the estimates obtained by the receptorial responsiveness method (RRM): a computer simulation study.
abstract: The receptorial responsiveness method (RRM) was proposed to characterize changes in the concentration of degradable agonists in the microenvironment of their receptors. The characterization is done by providing concentrations of a stable agonist for the same receptor that is equieffective with the change in concentration to be characterized. RRM is based on the analysis of concentration-effect (E/c) curves reflecting the simultaneous action of the degradable and the stable agonist. In the present study, we investigated whether dissimilar affinity and (or) efficacy of the coacting agonists as well as the steepness of the E/c curves influence the reliability of RRM. E/c curves were simulated based on the operational model and then analyzed with RRM. We found that dissimilarity in affinity of the coacting agonists did not affect the accuracy of RRM estimates. In contrast, accuracy of the estimation depended on the magnitude of the concentration to be assessed, the operational slope factor, and the operational efficacy ratio of the coacting agonists. However, our results suggest that proper choice of a stable agonist for a degradable one can help to ensure reliable results, since information about the change in concentration of a degradable agonist is otherwise difficult to obtain.
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy, University of Debrecen, P.O. Box 8, H-4012 Debrecen, Hungary.
authors.forename: Maria
authors.initials: M
authors.lastname: Grenczer
authors.forename: Akos
authors.initials: A
authors.lastname: Pinter
authors.forename: Judit
authors.initials: J
authors.lastname: Zsuga
authors.forename: Adam
authors.initials: A
authors.lastname: Kemeny-Beke
authors.forename: Bela
authors.initials: B
authors.lastname: Juhasz
authors.forename: Peter
authors.initials: P
authors.lastname: Szodoray
authors.forename: Arpad
authors.initials: A
authors.lastname: Tosaki
authors.forename: Rudolf
authors.initials: R
authors.lastname: Gesztelyi
mesh_terms: D015982:Bias; D003198:Computer Simulation; D004305:Dose-Response Relationship, Drug; D008954:Models, Biological; D011955:Receptors, Drug / Q000819:agonists* / Q000378:metabolism
chemical_list: D011955:Receptors, Drug