['To investigate the effects of endothelin-1 (ET-1) overexpression on apoptosis of the rat pulmonary arterial microvascular smooth muscle cells (RPMC) in vitro.', "Primary RPMC obtained from the pulmonary artery and lung microvasculature were identified by immunofluorescence staining and electron microscope technique. The RPMC was transient transfected with the pMEXneo-ET1 and pCDNA5-FRT-TO-ET1-3'UTR plasmids as well as the empty vector respectively via lipofectamine. Flow cytometry was used to assess the cell cycle and apoptosis of RPMC. Akt and Caspase-3 expressions were detected by Western blot and real time RT-PCR.", 'The mRNA of ET(A) expression was significantly higher than that of ET(B) receptor in primary RPMC. Flow cytometry analysis revealed significantly reduced apoptosis in ET-1 transfected RPMC compared to that in vehicle transfected RPMC. Overexpression of ET-1 in RPMC also significantly increased the phosphorylation of Akt and reduced the cleaved Caspase-3 expression.'] Does [ Endothelin-1 overexpression inhibit rat pulmonary arterial microvascular smooth muscle cell apoptosis via Akt/PKB pathway ]?