title: Effects of various selective phosphodiesterase inhibitors on relaxation and cyclic nucleotide contents in porcine iris sphincter.
abstract: The effects of various selective phosphodiesterase (PDE) inhibitors on muscle contractility and cyclic nucleotide contents in porcine iris sphincter were investigated. Forskolin and sodium nitroprusside inhibited carbachol (CCh)-induced contraction in a concentration-dependent manner. Various selective PDE inhibitors, vinpocetine (type 1), erythro -9-(2-hydroxy-3-nonyl)adenine (EHNA, type 2), milrinone (type 3), Ro20-1724 (type 4) and zaprinast (type 5), also inhibited CCh-induced contraction in a concentration-dependent manner. The rank order of potency of IC(50) was zaprinast > Ro20-1724 > EHNA >/= milrinone > vinpocetine. In the presence of CCh (0.3 muM), vinpocetine, milrinone and Ro20-1724 increased cAMP, but not cGMP, contents. In contrast, zaprinast and EHNA both increased cGMP, but not cAMP, contents. This indicates that vinpocetine-, milrinone- and Ro20-1724-induced relaxation is correlated with cAMP, while EHNA- and zaprinast- induced relaxation is correlated with cGMP in porcine iris sphincter.
authors: Laboratory of Veterinary Surgery, Nippon Veterinary and Life Science University, Musashino, Tokyo, Japan. yogo3@nvlu.ac.jp
authors: Takuya
authors: T
authors: YOGO
authors: Takeharu
authors: T
authors: KANEDA
authors: Yoshinori
authors: Y
authors: NEZU
authors: Yasuji
authors: Y
authors: HARADA
authors: Yasushi
authors: Y
authors: HARA
authors: Masahiro
authors: M
authors: TAGAWA
authors: Norimoto
authors: N
authors: URAKAWA
authors: Kazumasa
authors: K
authors: SHIMIZU
mesh_terms: D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology*; D005260:Female; D007498:Iris / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009599:Nitroprusside / Q000494:pharmacology*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D013552:Swine / Q000502:physiology*; D046509:Tissue Culture Techniques
chemical_list: D010726:Phosphodiesterase Inhibitors; D009599:Nitroprusside; D005576:Colforsin; D002217:Carbachol