Evidence for expression and function of phosphodiesterase type 5 (PDE-V) in rat resistance arteries

Evidence is provided for expression and a functional role for phosphodieste rase type V (PDE-V) in the rat isolated small mesenteric artery. The revers e transcription polymerase chain reaction (RT-PCR) demonstrated mRNA for PD E-V, while Western blotting and immunocytochemical studies showed correspon ding protein expression. Smooth muscle relaxation to the nitric oxide donor , diethylamine NONOate (DEA NONOate; 1 nM-10 muM; pEC(50)=6.7+/-0.3) was po tentiated significantly by the specific inhibitor of PDE-V, 4-[[3,4-(methyl enedioxy)benzyl]amino]-6-chloroquinazoline (MBCQ; 1 muM; pEC(50)=10.5+/-0.0 4). These data show that PDE-V is expressed in both the smooth muscle and e ndothelial cells of a resistance artery, and the enzyme can significantly i nfluence nitric oxide-evoked vasorelaxation.