acetylcholine ( ach ) produced specific inhibition of na , k-atp-ase activity in sarcolemmic preparations of the frog heart ( k0.5 = 1 microm ) , dog atria ( k0,5 = 5 microm ) and ventricles ( k0.5 = 1 microm ) , and dog small intestinal smooth muscles ( k0,5 = 0.5 microm ) .
C0018787
heart
C0018792
atria