Which of the following best describes a current working hypothesis about the molecular mechanism of action of lithium?

Correct Answer: A

Rationale: The correct answer is A. Increased synthesis of adenylyl cyclase. One of the leading hypotheses about the molecular mechanism of action of lithium is its ability to increase the synthesis of adenylyl cyclase. Adenylyl cyclase is an enzyme involved in the production of cyclic adenosine monophosphate (cAMP), which plays a role in cellular signaling pathways. By increasing the synthesis of adenylyl cyclase, lithium may help to regulate intracellular signaling and neurotransmitter release, contributing to its mood-stabilizing effects in bipolar disorder.

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: C

Rationale: Bupropion is a medication that is commonly used to treat depression, ADHD, and smoking cessation. Given the woman's symptoms of feeling fearful, helpless, and worried, as well as her difficulty organizing thoughts and smoking habit, bupropion would be a suitable choice as it can address both depressive and attention deficit disorders, as well as aid in smoking cessation.

Correct Answer: D

Rationale: The opening of K+ channels on postsynaptic neurons is a key molecular action that mediates the analgesic effect of opioids like morphine. This action leads to hyperpolarization of the neuron, reducing its excitability and inhibiting pain transmission. Therefore, in a patient with severe pain due to multiple fractures, the opening of K+ channels by morphine would be the most likely mechanism responsible for the analgesic effect.

Correct Answer: D

Rationale: The patient self-injected what he believed to be heroin, which is commonly sold on the street. Fentanyl is a potent synthetic opioid that is often mixed with or sold as heroin due to its powerful effects. Therefore, the patient most likely took Fentanyl, as it is frequently associated with street drugs like heroin.