Vasodilation and Vasoconstrictive Modulation

Phenylephrine (PE, a vasoconstrictor), N^G-nitro-L-arginine methyl ester (L-NAME, an inhibitor of nitric oxide synthases (NOS)), bradykinin (a stimulator of NOS), indomethacin (a cyclooxygenase (COX) inhibitor), ODQ (1H- (1,2,4) oxadiazolo (4,3-a) quinoxalin-1-one, a selective inhibitor of soluble guanylyl cyclase (sGC)), and zaprinast (a selective inhibitor of cGMP-specific phosphodiesterases V and VI (PDE5/6)) were purchased from Sigma Aldrich, Germany. All chemicals and reagents used for making physiological salt solutions and other analyses were of analytical grade. bradykinin was dissolved in 0.1 M acetic acid; indomethacin was dissolved in ethanol, while zaprinast was dissolved in DMSO at 10 mM. Unless otherwise specified, all the drugs were dissolved in distilled water [17 , 22 (link)]. Of note, all experimental solutions of drugs were made fresh daily.