Erianin Relaxes Mouse Airway Smooth Muscle

Aim:The aim of this study was to find a new bronchodilator for the treatment of asthma.Methods:The effects of erianin on 80 mM K⁺?high K⁺?-and 100?M acetylcholine?ACh?-induced precontractions on mouse tracheal rings were observed using muscle tension measurement.The lung slice technique was used to measure the effect of erianin on the intrapulmonary trachea contraction.Patch clamp technique and calcium imaging system were used to study the effects of erianin on L-type voltage-dependent Ca²⁺channels?LVDCCs?-and store-operated Ca²⁺channels?SOCCs?-mediated currents,and these channels-mediated Ca²⁺influx in airway smooth muscle cells?ASMCs?,respectively;Western Blotting method was used to define whether erianin affects the phosphorylation of myosin phosphatase target subunit 1?MYPT1?that is one step of the Ca²⁺sensitization pathway.Results:We found that erianin inhibited high K⁺-or ACh-induced precontractions of mouse airway smooth muscle?ASM?.ACh-induced contractions were also partially inhibited by nifedipine,YM-58483 and Y-27632,which are a selective inhibitor of LVDCCs,SOCCs and ROCK.In addition,erianin inhibited the currents mediated by LVDCCs and SOCCs,and reduced intracellular Ca²⁺concentration and phosphorylation of MYPT1.Conclusion:Erianin inhibits ASM contraction by inhibiting LVDCCs and SOCCs and Ca²⁺sensitization,suggesting that erianin could be developed as a new bronchodilator.