Cutaneous responses to allergen after local pretreatment with beta-adrenoceptor stimulating and blocking agents

beta-Adrenoceptor stimulating agents possess anti-allergic effects in vitro and in vivo. To study the mechanism of action further we compared in 10 atopic subjects the effects on allergen-induced cutaneous reactions of intradermally (i.d.) injected prenalterol (1-10 microgram) terbutaline (2.5-250 ng) and KWD 2131 (100 ng-2.5 microgram), i.e. compounds with preferential actions on beta 1-, beta 2-adrenoceptors and on beta-adrenoceptors not fitting this classification. All injections were given according to a double-blind design. Terbutaline and KWD 2131 produced a dose-dependent inhibition of the skin reactions induced by injecting horse dander allergen 5 min later. Terbutaline was about 20 times as potent as KWD 2131 whereas prenalterol was inactive. Propranolol fully blocked the anti-allergic effect produced by terbutaline. The results suggest that the cutaneous anti-allergic effect of beta-adrenoceptor-stimulating drugs is mediated via activation of beta 2-adrenoceptors, possibly on the mast cell, resulting in inhibition of mediator release.