Effects of various selective phosphodiesterase inhibitors on relaxation and cyclic nucleotide contents in porcine iris sphincter.
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.
YOGO
Takuya
T
Laboratory of Veterinary Surgery, Nippon Veterinary and Life Science University, Musashino, Tokyo, Japan. yogo3@nvlu.ac.jp
KANEDA
Takeharu
T
NEZU
Yoshinori
Y
HARADA
Yasuji
Y
HARA
Yasushi
Y
TAGAWA
Masahiro
M
URAKAWA
Norimoto
N
SHIMIZU
Kazumasa
K
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
D010726:Phosphodiesterase Inhibitors; D009599:Nitroprusside; D005576:Colforsin; D002217:Carbachol