山梨医科大学雑誌　第17巻3号　069-074(2002)

＜Original Article＞
Effects of Sildenafil (Viagra TM) on the Cyclic AMP Hydrolyzing
Phosphodiesterase Activity in the Canine Heart Assessed Using
a Modified Enzymatic Fluorometric Assay Technique

Atsushi SUGIYAMA, Yoshiki SAEGUSA, Akira TAKAHARA
Masao SUGITA and Keitaro HASHIMOTO

Abstract: Sildenafil is a phosphodiesterase type-5(PDE5) inhibitor, but has stimulatory effects on heart in vivo and in vitro. We evaluated the effects of sildenafil on the cyclic AMP hydrolyzing PDE activity in a crude enzyme preparation made from the intact canine heart using the modified enzymatic fluorometric assay technique. The basal PDE activity was 485±47pmol/min/mg protein (n＝6).Sildenafil as well as a non-specific PDE inhibitor, 3-isobutyl-1-methylxanthine (IBMX) inhibited the PDE activity in a concentration-related manner. Significant inhibition at 1-10μmol/L of　sildenafil was almost equivalent to that of the same concentration of IBMX. These results suggest that　supra-therapeutic concentration of sildenafil may directly inhibit cyclic AMP hydrolyzing PDEs in the　intact heart.

Key words: Sildenafil, Phosphodiesterase, Enzymatic Fluorometric assay, Cyclic AMP




本文は、編集委員会の意向によりインターネットには公開しておりません。図書館等でご覧ください。

Texts are not availavle on Internet.



目次・Contentsに戻る