Most models of psychotropic drug action have emphasized effects on the
release or uptake of neurotransmitters as well as interactions with
receptors. Stimulation of neurotransmitter receptors triggers a complex
array of electrical and biochemical actions. Recent experimental advances
have greatly clarified the second messenger systems underlying
neurotransmitter actions, suggesting novel sites of action for psychotropic
agents. The authors emphasize the phosphoinositide system and the
implications of its involvement for the therapeutic actions of lithium.