Target proteins which a drug molecule binds are:

Correct Answer: D

Rationale: The correct answer is D: All of the above. Drug molecules can bind to a variety of target proteins, including receptors, ion channels, and carriers. Receptors are often targeted to modulate cellular signaling pathways. Ion channels are targeted to regulate the flow of ions across cell membranes. Carriers are targeted to facilitate the transport of molecules across cell membranes. Therefore, the correct answer is D because drug molecules can bind to all three types of target proteins for therapeutic effects. Choices A, B, and C are incorrect because they each represent only one type of target protein that drug molecules can interact with, whereas the correct answer encompasses all possibilities.

Correct Answer: A

Rationale: The correct answer is A, Pralidoxime, as it is a cholinesterase reactivator used to treat organophosphate poisoning by reactivating inhibited acetylcholinesterase. Edrophonium (B) is a cholinesterase inhibitor used for diagnostic purposes. Pilocarpine (C) is a muscarinic agonist used to treat glaucoma and dry mouth. Isoflurophate (D) is an irreversible cholinesterase inhibitor used as an insecticide. Therefore, Pralidoxime is the only cholinesterase activator among the options provided.

Correct Answer: D

Rationale: The correct answer is D because hexamethonium is a ganglionic blocker that inhibits the sympathetic nervous system, leading to reduced peripheral vascular resistance and venous return (Choice A), partial mydriasis and loss of accommodation (Choice B), and constipation and urinary retention (Choice C). Stimulation of thermoregulatory sweating is not a systemic effect of hexamethonium, making Choice D incorrect. Hexamethonium does not affect the thermoregulatory sweating mechanism in the body.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Norepinephrine is a direct-acting sympathomimetic that stimulates alpha1, alpha2, and beta1 receptors. 2. Activation of alpha1 receptors causes vasoconstriction. 3. Activation of alpha2 receptors inhibits norepinephrine release. 4. Activation of beta1 receptors increases heart rate and contractility. Summary: A. Isoproterenol is a non-selective beta agonist. B. Ephedrine acts mainly by releasing norepinephrine. C. Dobutamine is a beta1-selective agonist. D. Norepinephrine is the correct choice as it stimulates alpha1, alpha2, and beta1 receptors.

Correct Answer: D

Rationale: The correct answer is D: Αlfa-receptor antagonists. Alpha-receptor antagonists, such as phenoxybenzamine and phentolamine, are used in the management of pheochromocytoma to block the effects of excess catecholamines released by the tumor. These agents help control hypertension and other symptoms associated with pheochromocytoma. A: Selective beta2-receptor antagonists are not typically used in the management of pheochromocytoma because they do not target the alpha-receptors responsible for the symptoms. B: Nonselective beta-receptor antagonists may be used as adjunct therapy in pheochromocytoma to control tachycardia, but they do not directly address the alpha-receptor effects. C: Indirect-acting adrenoreceptor antagonist drugs do not specifically target the alpha-receptors involved in pheochromocytoma symptoms. In summary,