Identification of a beta 2-adrenergic receptor in mammalian epidermis

The presence of a beta₂-adrenergic receptor in the epidermis has been demonstrated, based on the following pieces of information: (1) the addition of salbutamol, a beta₂-agonist, to slices of epidermal tissue increased the levels of cyclic AMP in the tissue above control levels in a dose-dependent manner with a maximum response after 5 min of incubation in 5 × 10^?5 M salbutamol, (2) the addition of butoxamine, a beta₂-antagonist, in conjunction with isoproterenol or salbutamol reduced the epidermal cyclic AMP levels when compared to levels obtained with agonist alone, (3) practolol, a beta₁-antagonist. had little effect on the salbutamol-induced increases in the cyclic AMP levels and further elevated the levels of cyclic AMP obtained by the addition of isoproterenol, (4) the addition of propranolol to the tissue in conjunction with isoproterenol or salbutamol reduced the levels of cyclic AMP to near control values, and (5) Ro 20-1724, a cyclic nucleotide phosphodiesterase inhibitor, maintained the salbutamolelevated cyclic AMP levels for a longer period of time.