Buprenorphine is

Correct Answer: A

Rationale: The correct answer is A because buprenorphine is a partial agonist at the Mu receptor. This means it can activate the receptor but with less efficacy compared to a full agonist, resulting in a ceiling effect and lower risk of respiratory depression. Choice B is incorrect because buprenorphine is not a full agonist at the Mu receptor. Choices C and D are incorrect as buprenorphine primarily acts on the Mu receptor, not the K receptor.

Correct Answer: A

Rationale: Bradykinin is a peptide that causes vasodilation, pain, and an increase in vascular permeability. However, it does not directly cause bronchodilation. This is because bradykinin primarily acts on blood vessels and capillaries, leading to increased blood flow and leakage of fluids, but it does not have a direct effect on the smooth muscle of the bronchioles. Therefore, the correct answer is A. Vasodilation, not bronchodilation. Choices B, C, and D are incorrect because they are all known actions of bradykinin based on its physiological effects.

Correct Answer: A

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

Correct Answer: C

Rationale: The correct answer is C (Both). Serotonin agonists like buspirone are used as anxiolytics by acting on serotonin receptors. Sumatriptan is used for migraines by constricting blood vessels and blocking pain pathways. Therefore, both options A and B are correct. Option D is incorrect because both buspirone and sumatriptan have clinical uses as serotonin agonists.

Correct Answer: D

Rationale: CNS stimulant agents belong to multiple categories, including respiratory stimulants that increase breathing, psychomotor stimulants that enhance physical activity, and psychomimetic agents that induce hallucinations or altered perceptions. Therefore, the correct answer is D, "All of the above," as CNS stimulants can have effects on various functions in the central nervous system. Choices A, B, and C are incorrect because CNS stimulants do not exclusively belong to any single category, but rather have a broad range of effects on different aspects of brain function.