LargeconductanceCa~(2+)-activatedK~+(BK_(Ca))channelexhibitsaphenotype-dependentexpressiononvascularsmoothmusclecells(VSMCs),whichpreferstocontractilephenotype.Meanwhile,shearstressdefinitelyinfluencesVSMCsproliferationandcontraction.Thereby,ahypothesiswasraised,wouldshearstresschangetheBK_(Ca)expressionandcorrelatewithVSMCphenotype?Inordertoinvestigateit,VSMCswereexposedtoshearstressinaparallel-plateflowchamberwith12dynes/cm~2for12h.Subsequently,theeffectofshearstressonVSMCproliferation,BK_(Ca)channelexpressionandcontractilephenotypemarker,α-smoothmusclecellactin(α-SMA)andsmoothmusclemyosinheavychain(SMMHC),wasdeterminedbyimmunofluorescencemicroscopy,flowcytometeryaswellasreversetranscriptionpolymerasechainreaction(RT-PCR),respectively.DatashowthatshearstressenhancedtheexpressionofBK_(Ca)channelwhileinhibitingVSMCproliferation.Paralleledtothosephenomena,theexpressionofbothα-SMAandSM-MHCweredecreasedsignificantly.TheseresultsdemonstratedthatupregulationofBK_(Ca)channelwasirrelevanttothemaintenanceVSMCofcontractilephenotypeundershearstress.ThisfindingprovidesanewinsightintounderstandingthecorrelationofBK_(Ca)channelandVSMCphenotype.
