Compared with epinephrine, norepinephrine produces all of the following effects EXCEPT:

Correct Answer: B

Rationale: Step 1: Norepinephrine is a neurotransmitter that acts on both alpha and beta receptors. Step 2: Norepinephrine has more potent effects on alpha receptors compared to epinephrine. Step 3: Choice A is correct as norepinephrine has similar effects on beta1 receptors in the heart and similar potency at alpha receptors. Step 4: Choice C is incorrect as tissue necrosis is associated with dopamine, not norepinephrine. Step 5: Choice D is incorrect as norepinephrine increases both diastolic and systolic blood pressure. Step 6: Choice B is correct as norepinephrine does not decrease mean pressure below normal before returning to the control value, making it the exception among the effects listed.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Barbiturates have a low therapeutic index, leading to a narrow range between therapeutic and toxic doses. They suppress REM sleep, which can lead to negative effects on sleep quality. Barbiturates also have a high potential for physical dependence and abuse, making them less desirable compared to benzodiazepines. Therefore, all the given reasons collectively contribute to the shift towards using hypnotic benzodiazepines over barbiturates.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Valproate's mechanism of action involves multiple pathways. 1. Valproate facilitates GABA synthesis by inhibiting GABA breakdown enzyme and enhancing GABA accumulation. 2. It inhibits voltage-sensitive Na+ channels, reducing neuronal excitability. 3. It also inhibits low threshold (T-type) Ca2+ channels, further reducing neuronal excitability. These combined actions lead to increased GABAergic transmission and decreased excitatory neurotransmission, contributing to its antiepileptic and mood stabilizing effects. Other choices are incorrect because they do not encompass all the mechanisms involved in valproate's action.

Correct Answer: D

Rationale: The correct answer is D: All of the above. In the antinociceptive descending pathways, multiple endogenous opioids play a role in pain modulation. Beta-endorphin, met- and leu-enkephalin, and dynorphin all act as chemical mediators to inhibit pain signals. Each of these opioids bind to different opioid receptors in the central nervous system, contributing to the overall analgesic effect. Therefore, the correct answer includes all three options as they collectively participate in the antinociceptive pathways. Choices A, B, and C alone are not sufficient to fully explain the complexity of the pain modulation system, making option D the most comprehensive and accurate choice.

Correct Answer: D

Rationale: The correct answer is D: Acetaldehyde. Disulfiram inhibits the enzyme aldehyde dehydrogenase, leading to accumulation of acetaldehyde when alcohol is consumed. Acetaldehyde buildup causes unpleasant symptoms like flushing, nausea, and headache. Formaldehyde (A) is not directly related to this interaction. Acetate (B) is a product of alcohol metabolism, not affected by disulfiram. Formic acid (C) is associated with methanol toxicity, not disulfiram-alcohol reaction. Therefore, the correct answer is D, as it aligns with the mechanism of action of disulfiram.