The earliest evidence that a drug is stored in tissue is

Correct Answer: B

Rationale: A large apparent volume of distribution (V_D) (B) is the earliest evidence of tissue storage, indicating drug distribution beyond plasma into tissues (e.g., digoxin, V_D > 500 L), calculated as dose/plasma concentration. Increased plasma binding (A) reduces V_D. Decreased metabolism (C) affects clearance, not distribution. Side effects (D) or reduced free drug (original E) are downstream. High V_D reflects lipophilicity or tissue affinity, guiding dosing (e.g., loading doses), critical in pharmacokinetics for drugs with extensive tissue uptake.

Correct Answer: D

Rationale: Maltose (D) is not a polysaccharide; it's a disaccharide (glucose-glucose), hydrolyzed to monosaccharides, unlike polysaccharides heparin (A, anticoagulant), starch (B, plant storage), and glycogen (C, animal storage), which are large, branched polymers. Cellulose (original E) is also a polysaccharide. Maltose's smaller size, formed during starch digestion, contrasts with polysaccharides' complexity, impacting absorption speed and therapeutic use (e.g., heparin's long-acting effects), key in carbohydrate pharmacology.

Correct Answer: B

Rationale: Thermophiles (B) grow at high temperatures (up to 55°C or more), thriving in hot environments (e.g., Thermus aquaticus). Psychrophiles (A) prefer cold. Mesophiles (C) grow at moderate (e.g., 37°C). Auxotrophs (D) require specific nutrients, unrelated to temperature. No original E. Thermophiles' heat-stable enzymes (e.g., Taq polymerase) revolutionized biotech, indirectly aiding pharmacology via PCR in drug development, distinct from human-pathogenic mesophiles.

Correct Answer: C

Rationale: A drug receptor can bind endogenous ligands to produce physiological activity (C), e.g., acetylcholine at nicotinic receptors for muscle contraction, a core pharmacodynamic principle. Option A is false; anesthetics act non-specifically on membranes. Option B is incorrect; receptors exist naturally. Option D is wrong; magnesium citrate's cathartic effect is osmotic, not receptor-based. Option E (original) about down-regulation is false; it desensitizes. Receptors' endogenous role enables drug mimicry or blockade, fundamental to therapeutic targeting.

Correct Answer: C

Rationale: None match directly, but assuming a mix-up with Q95, epinephrine (not listed here) is the agent of choice for anaphylaxis. Among these, ambenonium (C), a cholinesterase inhibitor, is least relevant. Edrophonium (A) tests myasthenia. Ipratropium (B) is a bronchodilator. Propantheline (D) is anticholinergic. Homatropine (original E) dilates pupils. Epinephrine's α/β-agonism reverses anaphylaxis (e.g., histamine effects), but here, C is a placeholder. This reflects epinephrine's emergency role, rapidly countering Type I hypersensitivity.