Following mediators are involved in acute inflammation except

Correct Answer: C

Rationale: Interferons are involved in antiviral defense and immune modulation, not acute inflammation.

Correct Answer: B

Rationale: Morphine treats MI pain (choice A), postoperative pain (choice C), and pulmonary edema (choice D) by reducing pain and preload. Head injury pain (choice B) contraindicates it due to respiratory depression and ICP risks. This exception guides safe use.

Correct Answer: B

Rationale: Benzodiazepines (e.g., diazepam, lorazepam) are CNS depressants used for anxiety, seizures, and insomnia. They exert effects by binding to a specific allosteric site on the GABAa receptor, enhancing GABA's inhibitory action. GABA, the primary inhibitory neurotransmitter, opens chloride (Cl⁻) channels, hyperpolarizing neurons and reducing excitability. Benzodiazepines increase the frequency of channel opening, potentiating this effect, leading to sedation and anxiolysis. Blocking Cl⁻ channels (choice A) would oppose inhibition, contrary to their purpose. Acting as direct agonists (choice C) is incorrect—they don't activate the receptor alone but amplify GABA's action. Antagonizing GABAb receptors (choice D) is irrelevant, as benzodiazepines target GABAa specifically. This potentiation mechanism underlies their therapeutic utility and risks like tolerance. Understanding this is key to distinguishing benzodiazepines from other CNS drugs and managing their clinical use effectively.

Correct Answer: D

Rationale: Ketamine can increase heart rate and is contraindicated in conditions like sick sinus syndrome.

Correct Answer: A

Rationale: High-potency antipsychotics have fewer anticholinergic side effects (e.g., dry mouth, constipation) compared to low-potency antipsychotics, but they are more likely to cause extrapyramidal symptoms like parkinsonism.