we conclude that beta-adrenergic modulation of ik is mediated by cyclic amp-dependent phosphorylation but not by an increase in [ ca2+ ] i , that pka and pkc enhance ik independently , and that acetylcholine antagonizes beta-adrenergic stimulation of ik most probably by inhibiting adenylate cyclase .
C0031715
phosphorylation
C0033640
pka