Bifunctional Action of Imipramine on Protein Kinase C from Rabbit Platelets in Vitro

Protein kinase C from rabbit platelets in vitro is inhibited by 1.0 mM imipramine, which is a tricyclic antidepressant. However, 0.2 mM imipramine activated protein kinase C activity from rabbit platelets. Imipramine had a bifunctional action to protein kinase C from platelets in vitro. It is reported that activation of protein kinase C is associated with inhibition of monoamine reuptake in platelets. It is supposed that inhibitory effect of 5-HT uptake of imipramine may, at least in part, be associated with its stimulatory effect on protein kinase C.