Monoamine oxidase enzyme (MAO) is responsible for:

Correct Answer: C

Rationale: Monoamine oxidase enzyme (MAO) is responsible for the degradation of neurotransmitters like adrenaline. MAO breaks down adrenaline into inactive metabolites, regulating its levels in the body. This process is crucial for maintaining neurotransmitter balance. Choice A is incorrect because MAO does not activate adrenaline. Choice B is incorrect as MAO is not involved in adrenaline synthesis. Choice D is incorrect as MAO does not degrade acetylcholine, but rather neurotransmitters like serotonin, dopamine, and adrenaline.

Correct Answer: D

Rationale: The correct answer is D because acidification of urine actually increases the excretion of amphetamine. Step 1: Amphetamine is an indirect acting sympathomimetic, which means it stimulates the release of norepinephrine. Step 2: It has prominent CNS action by increasing the release of dopamine and norepinephrine, leading to effects like increased alertness and euphoria. Step 3: Chronic use of amphetamine can indeed lead to addiction due to its reinforcing properties and impact on the brain's reward system. Therefore, D is incorrect as acidification of urine does not decrease amphetamine excretion; instead, it can enhance excretion by increasing its solubility in urine.

Correct Answer: A

Rationale: Sumatriptan is the correct answer for treating acute migraine attacks as it is a specific serotonin receptor agonist that helps constrict blood vessels in the brain. Ergometrine and dihydroergometrine are ergot alkaloids used for other conditions, not migraine. Propranolol is a beta-blocker used for migraine prevention, not acute attacks.

Correct Answer: D

Rationale: Terbutaline specifically stimulates Beta2 receptors. This leads to bronchodilation by relaxing smooth muscles in the airways. Beta2 receptors are predominantly found in the lungs. Option A and B are incorrect as terbutaline does not target Alpha receptors. Option C is incorrect as terbutaline does not primarily stimulate Beta1 receptors, which are mainly found in the heart.

Correct Answer: B

Rationale: The correct answer is B: Metoprolol. Metoprolol is a cardioselective beta-1 blocker, meaning it primarily blocks beta-1 receptors in the heart, leading to a decrease in heart rate and contractility. This selectivity reduces the risk of bronchoconstriction compared to non-selective beta blockers like Timolol (Choice A), Nadolol (Choice C), and Sotalol (Choice D), which can also block beta-2 receptors in the lungs, potentially causing respiratory issues in patients with asthma or COPD. Therefore, Metoprolol is the best choice for patients with cardiovascular conditions who also have respiratory concerns.