Adenosine Triphosphate Animalia Animals Aorta, Thoracic Bradykinin Cells, Cultured Cyclic GMP Endothelium, Vascular Endothelium-dependent relaxing factor Enzyme Activation Enzyme Inhibitors Fetus Kinetics NG-Nitroarginine Methyl Ester Naphthalenes Nitric Oxide Phorbol Esters Phorbol ester Polyethylene Glycols Protein Kinase C Protein kinase C inhibitors Staurosporine Suidae Sus scrofa Swine Tetradecanoylphorbol Acetate Time Factors Vasodilator Agents adenosine triphosphate animal cell