Apelin isoforms have comparable potencies at the apelin receptor expressed on cardiomyocytes, vascular endothelial and smooth muscle cells from human isolated cardiovascular tissue
EC50 values are geometric means. Values are mean ± S.E.M.
| Action | [Pyr1]Apelin-13 | Apelin-13 | Apelin-36 | ||||||
|---|---|---|---|---|---|---|---|---|---|
| EC50 | pD2 | EMAX | EC50 | pD2 | EMAX | EC50 | pD2 | EMAX | |
| Inotropya | 0.1 | 9.9 ± 0.2 | 49% | 0.08 | 10.1 ± 0.3 | 64% | 0.04 | 10.4 ± 0.2 | 39% |
| Vasodilatationb | 1.6 | 8.8 ± 0.1 | 39% | 0.6 | 9.2 ± 0.2 | 51% | 0.8 | 9.1 ± 0.2 | 43% |
| Vasoconstrictionc | 1.6 | 8.8 ± 0.5 | 30% | 0.8 | 9.1 ± 0.2 | 19% | 0.6 | 9.2 ± 0.5 | 17% |
EC50, the concentration (nmol/l) of apelin peptide producing 50% of the maximum response to that peptide; EMAX, maximum response, expressed as a % of a reference stimulus; pD2, negative log10 EC50.
↵a Human, electrically paced atrial strip. Maximum response is % inotropic response to calcium (8.95 mmol/l).
↵b Endothelium-dependent vasodilatation in human mammary artery pre-constricted with ET-1. Maximum response (EMAX) is % reversal of ET-1 response.
↵c Contraction of endothelium-denuded saphenous vein. Maximum response (EMAX) is %KCL (100 mmol/l). Tissues were maintained in organ baths at 37°C in oxygenated physiologic saline (Maguire et al., 2009).