45-year-old man with a long history of bipolar disorder had been stable on a maintenance lithium treatment for the past year. Which of the following statements best describes a current working hypothesis about the molecular mechanism of action of lithium?
A. Increased synthesis of adenylyl cyclase B. Increased synthesis of inositol monophosphatase C. Increased serotonin reuptake into serotonergic terminals D. Up-regulation of beta adrenergic receptors E. Decreased synthesis of IP3 and DAG F. Increased glutamatergic activity
Decreased synthesis of ip3 and dag-learning objective: explain the molecular mechanisms of action of lithium.answer: elithium inhibits inositol monophosphatase, an enzyme involved in the phosphatidylinositolpathway. this leads to depletion of pip2, which is the precursor of both ip3 and dag. thereforethe synthesis of ip3 and dag is inhibited and the activity of many receptors that are ip3/daglinked is depressed. this could cause an inhibition of overactive circuits in mania.a, b, c, d, f) actually lithium causes actions opposite to those listed.