The antidepressant imipramine inhibits M current by activating a phosphatidylinositol 4,5-bisphosphate (PIP2)-dependent pathway in rat sympathetic neurones.

Little is known about the intracellular actions of imipramine (IMI) in the regulation of ion channels. We tested the action of IMI on the intracellular cascade that regulates M current (I(M)) in superior cervical ganglion neurones (SCGs). Dialysis of the cells with GDPbetaS, a G protein signaling blocker, did not disrupt the inhibition of I(M).