Which of the following effects is associated with beta3-receptor stimulation?

Correct Answer: A

Rationale: The correct answer is A: Lipolysis. Beta3-receptors are mainly found in adipose tissue and their stimulation leads to the breakdown of triglycerides into free fatty acids, promoting lipolysis. This effect is beneficial in increasing energy expenditure and weight loss. Explanation for why the other choices are incorrect: B: Decrease in platelet aggregation - This effect is associated with beta2-receptor stimulation, not beta3. C: Bronchodilation - This effect is primarily mediated by beta2-receptor stimulation in the lungs. D: Tachycardia - Stimulation of beta1-receptors, not beta3, is responsible for increasing heart rate.

Correct Answer: D

Rationale: The correct answer is D because alterations in hepatic function due to disease can affect drug metabolism, old age can alter drug clearance rates, and drug-induced changes in microsomal enzyme activities can impact drug metabolism. Each factor directly influences the biodisposition of hypnotic agents by affecting their metabolism and elimination. Therefore, all of the factors mentioned in choices A, B, and C can influence the biodisposition of hypnotic agents.

Correct Answer: B

Rationale: The correct answer is B: Primidone. Primidone is a prodrug that is metabolized in the liver to phenobarbital, which is the active antiseizure component. This process allows for a more controlled and sustained release of phenobarbital in the body. Phenytoin (A) works by blocking sodium channels, Felbamate (C) works by multiple mechanisms, and Vigabatrin (D) works by increasing GABA levels. These mechanisms are different from Primidone's pathway of being converted into phenobarbital.

Correct Answer: C

Rationale: Rationale: MAO-A primarily metabolizes norepinephrine and serotonin, as these neurotransmitters are broken down in the synaptic cleft. MAO-B mainly metabolizes dopamine. Thus, choice C is correct. Choices A, B, and D are incorrect because they inaccurately assign the neurotransmitters to MAO-A and MAO-B, leading to an incorrect understanding of their functions.

Correct Answer: D

Rationale: The correct answer is D because alcohol abuse can lead to various medical complications, including liver failure (choice A), tolerance and physical dependence (choice B), and nerve injury, ataxia, and dementia (choice C). Liver cirrhosis is a well-known consequence of chronic alcohol abuse due to liver damage. Tolerance and physical dependence develop with prolonged alcohol consumption. Nerve injury, ataxia, and dementia can result from alcohol-related vitamin deficiencies and neurotoxic effects. Therefore, all of the choices are common medical complications of alcohol abuse.