(R)-(-)-Phenylephrine is a selective α 1 -adrenoceptor agonist with pK i values of 5.86, 4.87 and 4.70 for α 1D , α 1B and α 1A receptors respectively. Phenylephrine promotes cardiac fibroblast proliferation. Phenylephrine activates CaN and evokes NFAT3 nuclear translocation. It suggests that the Ca( 2+ )/CaN/NFAT pathway mediates phenylephrine -induced cardiac fibroblast proliferation, and this pathway might be a possible therapeutic target in cardiac fibrosis.
Perfusion of hearts with 100 μM phenylephrine causes a rapid (maximal at 10 min) 12-fold activation of two p38-MAPK isoforms. α 1 -adrenoceptor agonists such as phenylephrine increase the contractility of the heart. Phenylephrine also activates SAPKs/JNKs in neonatal ventricular myocytes. Phenylephrine could increase the alveolar fluid clearance in high tidal volume-ventilated rats and accelerate the absorption of pulmonary edema.