Beta2 receptor stimulation includes all of the following effects EXCEPT:

Correct Answer: D

Rationale: Beta2 receptor stimulation primarily leads to vasodilation, bronchodilation, and relaxation of smooth muscles in non-cardiac tissues. It does not cause tachycardia, which is primarily mediated by Beta1 receptor stimulation. Therefore, option D is the correct answer. Option A is incorrect because Beta2 stimulation does not stimulate renin secretion. Option B is incorrect as Beta2 stimulation increases potassium concentration in plasma. Option C is incorrect as Beta2 stimulation causes relaxation of bladder and uterus muscles.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Barbiturates are known to increase the metabolism of various drugs, including anticoagulants, digitalis compounds, and glucocorticoids. This is because barbiturates induce liver enzymes responsible for drug metabolism, leading to faster clearance of these medications from the body. Therefore, the correct answer is D as barbiturates can affect the metabolism of all the mentioned drug classes. Choices A, B, and C are incorrect as barbiturates do not selectively increase the metabolism of only one of these drug classes, but rather have a broad impact on drug metabolism.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Phenobarbital binds to an allosteric regulatory site on the GABA-BZ receptor. 2. It enhances the affinity of GABA to its receptor, increasing Cl- channel opening duration. 3. This leads to hyperpolarization and inhibits neuronal excitability, preventing seizures. 4. Diazepam (A) and Valproate (B) act on different receptors. 5. Topiramate (D) modulates ion channels but not through the GABA-BZ receptor. Summary: Phenobarbital is the correct answer as it directly targets the GABA-BZ receptor, increasing Cl- channel opening duration. Diazepam, Valproate, and Topiramate act through different mechanisms, making them incorrect choices.

Correct Answer: B

Rationale: The correct answer is B: Bromocriptine. Bromocriptine is a dopamine agonist that can reduce prolactin levels by stimulating dopamine receptors in the pituitary gland. This makes it effective in treating hyperprolactinemia. Benztropine (A) is an anticholinergic used for Parkinson's symptoms, not hyperprolactinemia. Amantadine (C) is an antiviral and weak dopamine agonist primarily used for Parkinson's. Levodopa (D) is a precursor to dopamine and is used for Parkinson's symptoms but not hyperprolactinemia.

Correct Answer: C

Rationale: The correct answer is C: Alcohol increases body heat loss. When alcohol is consumed, it causes blood vessels near the skin to dilate, resulting in increased blood flow to the skin's surface. This leads to heat being lost from the body, causing a drop in core body temperature. Choices A and B are incorrect because alcohol actually decreases body temperature by increasing heat loss. Choice D is also incorrect because alcohol does affect body temperature by promoting heat loss.