A 7-year-old boy is brought to the emergency department by his parents after being stung by a bee. The parents say that he is allergic to bee stings, and the patient is having great difficulty breathing. Epinephrine is administered immediately. His symptoms improve as molecules of epinephrine bind to β\(_2\)-receptors in bronchial smooth muscle. Which of the following describes a feature of β\(_2\)-receptors?

Correct Answer: A

Rationale: β\(_2\)-adrenergic receptors are G-protein-coupled receptors that have seven transmembrane domains, which is a characteristic feature of this receptor family.

Correct Answer: D

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

Correct Answer: A

Rationale: Newer antiepileptic drugs like ethosuximide and valproate are effective in treating absence seizures which are generalized brief and involve loss of consciousness.

Correct Answer: D

Rationale: H1 receptor antagonists have minimal impact in reversing extrapyramidal symptoms, which are best addressed by anticholinergics.

Correct Answer: B

Rationale: EDTA is effective for chelation therapy in lead and zinc poisoning but it is not used for iron poisoning as iron chelation requires a different agent like deferoxamine.