Epinephrine-induced cyclic AMP accumulation in the psoriatic epidermis.
Although there are many reports concerning different beta-adrenergic responsiveness in involved and uninvolved skin of psoriasis, previous experiments have been done mainly by using keratome-sliced skin, which contains unknown amounts of stratum corneum, dermis, skin appendages, etc. In order to determine the effect of epinephrine on the cyclic AMP level of 'pure' epidermis in psoriasis, a microdissection technique was employed. Basal levels of cyclic AMP in the involved epidermis were slightly higher than in the uninvolved epidermis (involved 1.9 +/- 0.3 pmoles/mg dry weight; uninvolved 1.3 +/- 0.3 pmoles/mg d.w.). This difference was not statistically significant (p greater than 0.1). The response to epinephrine by the involved epidermis (8.4 +/- 1.0 pmoles/mg d.w.) was much lower than that in the uninvolved epidermis (23.3 +/- 4.3 pmoles/mg d.w.). The difference was statistically highly significant (p less than 0.005). Our data show that psoriatic involved epidermis per se had a reduced beta-adrenergic responsiveness, which might be significantly involved in the pathophysiology of psoriasis.