Relaxant Action ofPlumula NelumbinisExtract on Mouse Airway Smooth Muscle

Abstract

The traditional herbPlumula Nelumbinisis widely used in the world because it has many biological activities, such as anti-inflammation, antioxidant, antihypertension, and butyrylcholinesterase inhibition. However, the action ofPlumula Nelumbinison airway smooth muscle (ASM) relaxation has not been investigated. A chloroform extract ofPlumula Nelumbinis(CEPN) was prepared, which completely inhibited precontraction induced by high K+in a concentration-dependent manner in mouse tracheal rings, but it had no effect on resting tension. CEPN also blocked voltage-dependent L-type Ca2+channel- (VDCC-) mediated currents. In addition, ACh-induced precontraction was also completely blocked by CEPN and partially inhibited by nifedipine or pyrazole 3. Besides, CEPN partially reduced ACh-activated nonselective cation channel (NSCC) currents. Taken together, our data demonstrate that CEPN blocked VDCC and NSCC to inhibit Ca2+influx, resulting in relaxation of precontracted ASM. This finding indicates that CEPN would be a candidate of new potent bronchodilators.