Phosphodiesterase InhibitorsRolipramCyclic Nucleotide Phosphodiesterases, Type 43',5'-Cyclic-AMP PhosphodiesterasesCyclic Nucleotide Phosphodiesterases, Type 3Phosphodiesterase 4 InhibitorsPhosphoric Diester HydrolasesPurinonesMilrinone4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinonePhosphodiesterase 3 InhibitorsCyclic Nucleotide Phosphodiesterases, Type 7Cyclic Nucleotide Phosphodiesterases, Type 1PyrrolidinonesCyclic Nucleotide Phosphodiesterases, Type 53',5'-Cyclic-GMP Phosphodiesterases1-Methyl-3-isobutylxanthineTheophyllineCyclic AMPPyridazinesCyclic GMPVinca AlkaloidsCyclic Nucleotide Phosphodiesterases, Type 2IsoenzymesNucleotides, CyclicPhosphodiesterase 5 InhibitorsPentoxifyllineSulfonesIsoproterenolColforsinXanthinesPurinesBucladesineGuinea Pigs