Characteristics of phentolamine include all of the following EXCEPT:

Correct Answer: B

Rationale: The correct answer is B: Stimulation of responses to serotonin. Phentolamine is an alpha-adrenergic blocker, causing vasodilation and reducing peripheral resistance (A). It can lead to tachycardia (C) due to its vasodilatory effects. Phentolamine does not stimulate muscarinic H1 and H2 histamine receptors (D). Serotonin receptors are not affected by phentolamine, making choice B the correct answer.

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.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Butyrophenone derivatives are a class of antipsychotic drugs. 2. Droperidol is a butyrophenone derivative, used for sedation and treating psychosis. 3. Thioridazine, Sertindole, and Fluphenazine are not butyrophenone derivatives. 4. Therefore, the correct answer is A, Droperidol. In summary: - A (Droperidol) is correct as it belongs to the butyrophenone derivative class. - B (Thioridazine), C (Sertindole), and D (Fluphenazine) are incorrect as they are not butyrophenone derivatives.