Effects of beta 2-adrenergic agonists on isolated guinea pig lung mast cells

The mast cell protective effects of the newly developed long-acting beta 2-agonists salmeterol and formoterol were compared with those of conventionally used beta 2-agonists, non-specific beta-agonists, disodium cromoglycate (DSCG) and theophylline. With the exception of DSCG, all the test agents inhibited ovalbumin-induced histamine release from enzymically dispersed guinea pig lung mast cells in a dose-dependent fashion. At the maximum concentration tested, theophylline produced the highest level of protection, inhibiting up to 90% of ovalbumin-induced histamine release whereas DSCG produced only 10% inhibition. The maximum inhibition produced by all the beta 2-agonists tested was around 45%. While salmeterol was equipotent with salbutamol, formoterol was at least a 100-fold more potent. Hence the present study confirmed the previously reported mast cell stabilizing actions of conventional beta 2-agonists and extended the observation to the newly developed long-acting analogues.