<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>Compounds which inhibit or antagonize the biosynthesis or actions of phosphodiesterases.</n0:def-definition><n0:def-source>MSH2002_06_01</n0:def-source></n0:ComplexDefinition>
<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>Any substance that inhibits phosphodiesterase, an enzyme that catalyzes the breaking of a phosphodiester bond. Usually, this refers to cyclic nucleotide phosphodiesterase, an enzyme that breaks the phosphodiester bond in the second messenger molecules cAMP and cGMP. Inhibition of cyclic nucleotide phosphodiesterase can be used to affect vasodilation.</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>