TASK Channel Expression inHumanPlacenta andCytotrophoblast Cells

K+channels TASK1and 2 in relation to gestationand differentiation, usingvilloustissuefromfirst and third trimester andcultured cytotrophoblast cells atmononucleate andmultinucleate stages ofculture. METHODS: Quantitative real-time polymerase chain reaction (PCR), immunofluorescence, and86Rb+ (K)eftiux wereused toinvestigate TASKchannel expression andfunction. RESULTS:TASK2mRNA expression washigher infirst trimester than term(10to13vs38to40weeks, P<.05). Other K+oa-subunit mRNAs,including TASK1,remained unaltered buttheregulatory BKa P-subunit, like TASK2, washigher infirst trimester than term(P<.001). Immunofluorescence showed that TASK2hadanintracellular localization within thetrophoblast offirst trimester villi butwasless abundant and restricted tostemvilli atterm.TASK2also showed intracellular localization inmononucleate cytotrophoblast cells inculture andexpression waslost with multinucleation. Bycontrast, TASK1waslocalised, independently ofcell nucleation, tocytotrophoblast cell plasma membranes. 86Rb+ (K)efflux was measured frommultinucleated cytotrophoblast cells. Bothbasal andpH 8.0-stimulated efflux was inhibited bytheTASK1antagonist anandamide (n= Sforboth conditions; P<.01andP<.001, respectively). CONCLUSION:TASK1and2areexpressed inplacental trophoblast cells andTASK1activity may have a role inregulating syncytiotrophoblast homeostasis and/or solute transportfiuncti ons. SocGynecol Investig 2006; 13:30-9) Copyright (©2006bytheSociety forGynecologic Investigation.