Phenylephrine HCl is a selective agonist of α1-adrenergic receptor [1].?
α1-adrenergic receptors are one of the three main families of adrenergic receptors regulating the actions of? norepinephrine and epinephrine [1].?
Phenylephrine exhibits significant selectivity for α1-adrenergic receptors subtypes. When tested with hamster α1B-AR, bovine α1C-AR , and rat αA/D-AR, Phenylephrine showed inhibition of I-BE binding with pKi?values of 4.87, 4.70 and 5.86 for α1B, α1C?and αA/D?receptors respectively and intrinsic activities of activating cloned α1-adrenergic receptors subtypes with pEC50 values of? 6.47, 6.77 and 7.01 for α1B, α1C?and αA/D?receptors respectively [1].?
In high?tidal?volume ventilated rats, ?although 1×10-9 mol/L phenylephrine did not raise alveolar fluid clearance, alveolar space injection of phenylephrine at different concentrations of 1×10-5, 1×10-6, 1×10-7 and 1×10-8 increased the alveolar fluid clearance and promoted the absorption of pulmonary edema in a dose-dependent manner. [2].?
References:
[1]. Minneman KP, Theroux TL, Hollinger S, et al. Selectivity of agonists for cloned alpha 1-adrenergic receptor subtypes. Molecular Pharmacology. 1994, 46(5):929-36.
[2]. Li NJ, Gu X, Li W, et al. Effect of phenylephrine on alveolar fluid clearance in ventilator-induced lung injury. Chinese Medical Sciences Journal. 2013, 28(1):1-6.
