sentences:  Ki equilibrium constants ~20-45 nanomolar) and Δ12-PGJ2 having 10-fold lesser potency, at least on mouse DP2 receptor.These PGJ2's also bind and activate a second G protein-coupled receptor, Prostaglandin DP1 receptor, but require high concentrations to do so; this activation is not considered physiological.DP2 and DP1 are G protein-coupled receptors, with the DP2 receptor coupled to Gi alpha subunit-dependent depression of cellular cAMP levels and causing the potentiation cell injury in neural tissue cultures and with the DP1 receptor coupled to Gs alpha subunit-dependent increases in cellular cAMP levels and the suppression of cell injury in neural tissue cultures.