Indicate the local anesthetic, which is more lipid-soluble:

Correct Answer: A

Rationale: The correct answer is A: Bupivacaine. Bupivacaine is more lipid-soluble compared to the other choices. Lipid solubility is an important factor in determining the potency and duration of action of local anesthetics. Bupivacaine has a higher lipid solubility due to its long carbon chain structure, allowing it to penetrate nerve membranes more effectively, resulting in a longer duration of action. Lidocaine, mepivacaine, and procaine are less lipid-soluble and have shorter durations of action compared to bupivacaine. Therefore, bupivacaine is the most lipid-soluble local anesthetic among the choices provided.

Correct Answer: D

Rationale: The correct answer is D: Succinylcholine. Succinylcholine has a "double-acetylcholine" structure because it contains two acetylcholine molecules linked together. This structure allows succinylcholine to act as a depolarizing neuromuscular blocker by mimicking the action of acetylcholine at the neuromuscular junction. Rocuronium (A) and Atracurium (C) are nondepolarizing neuromuscular blockers that do not have a double-acetylcholine structure. Carbachol (B) is a cholinergic agonist but does not have a double-acetylcholine structure like succinylcholine.

Correct Answer: A

Rationale: Rationale: Terbutaline is a beta2-selective agonist because it primarily targets beta2-adrenergic receptors in the lungs, leading to bronchodilation. Xylometazoline is an alpha-adrenergic agonist, Isoproterenol is a non-selective beta agonist, and Dobutamine primarily targets beta1-adrenergic receptors. Therefore, Terbutaline is the correct choice for beta2-selective agonist based on its pharmacological action.

Correct Answer: D

Rationale: The correct answer is D because the statement that the ALFA1a subtype mediates both vascular and prostate smooth muscle contraction is incorrect. The ALFA1a subtype primarily mediates prostate smooth muscle contraction, while the ALFA1b subtype is responsible for vascular smooth muscle contraction. This is a key distinction in understanding the roles of different subtypes of alfa1 receptors. Choices A, B, and C are all correct statements as there are indeed at least three subtypes of alfa1 receptors (alfa1a, alfa1b, and alfa1d), ALFA1a subtype does mediate prostate smooth muscle contraction, and ALFA1b subtype does mediate vascular smooth muscle contraction, respectively.

Correct Answer: C

Rationale: Flumazenil is a benzodiazepine receptor antagonist that reverses the effects of benzodiazepines like zolpidem, making choice C correct. Flumazenil does not block the actions of phenobarbital (choice A) or morphine (choice B) as they act on different receptors. Ethanol (choice D) is not affected by flumazenil. In summary, flumazenil specifically antagonizes benzodiazepines like zolpidem, making other choices incorrect.