GS-389
GS 389 ((±)-O,O-Dimethylcoclaurine) is a tetrahydroisoquinoline. GS-389 inhibites Cyclic AMP and cyclic AMP dependent phosphodiesterases from rat atrial and ventricular tissue. GS-389 relaxes the contraction induced by phenylephrine and high K+ in rat aortic rings[1].