1. Theophylline and 3-isobutyl-1-methylxanthine (IBMX) are relatively poor inhibitors of cyclic AMP phosphodiesterase from the ventricles of the bivalve Mercenaria mercenaria (I50 = 4.5 × 10-3 and 2 × 10-3 M, respectively). 2. At doses ≤10-4 M, these agents have no effect on myocardial contractility or cyclic AMP content. 3. However, IBMX (10-4 M) does potentiate the cardio-excitatory actions of a subthreshold of 5-hydroxytryptamine.
|Original language||English (US)|
|Number of pages||6|
|Journal||Comparative Biochemistry and Physiology. Part C, Comparative|
|State||Published - 1981|
ASJC Scopus subject areas