Analgesic, anti-inflammatory and antipyretic screening assays MCQs With Answer

Analgesic, anti-inflammatory and antipyretic screening assays MCQs With Answer

This blog provides an advanced yet clear set of multiple-choice questions tailored for M.Pharm students focusing on screening assays for analgesic, anti-inflammatory and antipyretic activities. It covers common in vivo and in vitro models (writhing, formalin, hot plate, tail-flick, carrageenan paw edema, cotton-pellet granuloma, yeast-induced pyrexia, LPS models), endpoints, standard reference drugs, mechanisms (COX inhibition, cytokine modulation, central vs peripheral analgesia), dose-response considerations and data interpretation. Questions emphasize experimental design, timing, calculation of percent inhibition and ethical aspects of animal use, helping students prepare for exams and practical research planning with conceptual depth and applied relevance.

Q1. The primary mechanism measured by the acetic acid-induced writhing test in mice is:

• Central opioid-mediated antinociception
• Peripheral antinociceptive activity mediated largely by prostaglandin synthesis inhibition
• Thermoregulatory changes due to hypothalamic action
• Direct inhibition of sodium channels in peripheral nerves

Correct Answer: Peripheral antinociceptive activity mediated largely by prostaglandin synthesis inhibition

Q2. Which assay is best suited to differentiate between central and peripheral analgesic activity?

• Acetic acid-induced writhing test
• Hot plate and tail-flick tests combined with naloxone antagonism
• Carrageenan-induced paw edema
• Cotton pellet granuloma

Correct Answer: Hot plate and tail-flick tests combined with naloxone antagonism

Q3. In the formalin test, the second (late) phase of nociceptive behavior primarily reflects:

• Direct activation of peripheral nociceptors only
• Central sensitization and inflammatory mediator involvement
• Thermal nociception mediated by TRPV1
• Pure neuropathic pain without inflammation

Correct Answer: Central sensitization and inflammatory mediator involvement

Q4. Which standard drug is typically used as a positive control for anti-inflammatory activity in the carrageenan-induced paw edema model?

• Morphine
• Aspirin (or indomethacin/ibuprofen)
• Pilocarpine
• Diazepam

Correct Answer: Aspirin (or indomethacin/ibuprofen)

Q5. The peak swelling in carrageenan-induced paw edema occurring at 3–5 hours is mainly mediated by:

• Histamine and serotonin release
• Bradykinin exclusively
• Prostaglandins and later-phase mediators like COX-2 products
• Immediate IgE-mediated allergic response

Correct Answer: Prostaglandins and later-phase mediators like COX-2 products

Q6. Which endpoint best quantifies analgesic effect in the hot plate test?

• Number of writhes per minute
• Latency to paw lick or jump after thermal stimulus
• Paw thickness measured by vernier caliper
• Body temperature drop in degrees Celsius

Correct Answer: Latency to paw lick or jump after thermal stimulus

Q7. The cotton pellet granuloma model is primarily used to assess which component of inflammation?

• Acute exudative inflammation only
• Subacute/chronic proliferative (granulomatous) inflammation
• Neurogenic pain responses
• Systemic fever induction

Correct Answer: Subacute/chronic proliferative (granulomatous) inflammation

Q8. When calculating percent inhibition of paw edema, which of the following is the correct formula?

• (Edema in treated / Edema in control) × 100
• ((Edema control − Edema treated) / Edema control) × 100
• ((Edema treated − Edema control) / Edema treated) × 100
• (Baseline paw volume / Final paw volume) × 100

Correct Answer: ((Edema control − Edema treated) / Edema control) × 100

Q9. Yeast-induced pyrexia in rodents is commonly used to screen antipyretic activity because yeast injection causes fever by:

• Direct heating of the body due to metabolic energy
• Induction of cytokines like IL-1 and PGE2 that act on the hypothalamus
• Blocking thermoregulatory set point via GABA receptors
• Physical irritation of skin thermoreceptors

Correct Answer: Induction of cytokines like IL-1 and PGE2 that act on the hypothalamus

Q10. Which in vitro assay would directly assess COX enzyme inhibition relevant to anti-inflammatory action?

• Radiant heat paw withdrawal test
• COX activity assay measuring conversion of arachidonic acid to prostaglandins
• Hot plate latency assay
• Passive avoidance test

Correct Answer: COX activity assay measuring conversion of arachidonic acid to prostaglandins

Q11. A test showing analgesic effect reversed by naloxone suggests involvement of which pathway?

• Peripheral prostaglandin inhibition
• Opioidergic (mu-opioid receptor) central pathway
• NMDA receptor blockade
• COX-2 selective inhibition

Correct Answer: Opioidergic (mu-opioid receptor) central pathway

Q12. In the tail-flick assay, an increase in tail withdrawal latency after drug treatment indicates:

• Increased peripheral inflammation
• Antinociceptive activity, typically spinally mediated
• Enhanced motor coordination
• Antipyretic efficacy

Correct Answer: Antinociceptive activity, typically spinally mediated

Q13. Which model is most appropriate to evaluate chronic inflammatory arthritis resembling human rheumatoid arthritis?

• Acetic acid-induced writhing
• Complete Freund’s adjuvant (CFA)-induced arthritis
• Hot plate test
• Yeast-induced pyrexia

Correct Answer: Complete Freund’s adjuvant (CFA)-induced arthritis

Q14. For ethical and statistical validity, the most important consideration when selecting animal group sizes in screening assays is:

• Choosing the maximum number of animals available
• Performing a priori power calculation to detect expected effect size
• Using a single animal per group to conserve resources
• Selecting group sizes based on convenience rather than variability

Correct Answer: Performing a priori power calculation to detect expected effect size

Q15. Which biochemical marker is commonly measured in plasma to support anti-inflammatory effects in experimental models?

• Plasma glucose only
• Serum prostaglandin E2 (PGE2) or TNF-α levels
• Urinary creatinine exclusively
• Serum acetylcholinesterase

Correct Answer: Serum prostaglandin E2 (PGE2) or TNF-α levels

Q16. A drug that reduces swelling in the early phase (0–2 h) but not the late phase of carrageenan edema likely acts by inhibiting:

• Neutrophil infiltration only
• Histamine/serotonin or bradykinin-mediated responses
• Fibroblast proliferation exclusively
• Adaptive immune responses (T-cell mediated)

Correct Answer: Histamine/serotonin or bradykinin-mediated responses

Q17. The formalin test’s early phase is sensitive to which class of analgesics?

• Anti-inflammatory agents only
• Central acting analgesics like opioids
• Antipyretics only
• Antibiotics

Correct Answer: Central acting analgesics like opioids

Q18. In antipyretic screening, LPS-induced fever models are particularly useful to study drugs that modulate:

• Peripheral nociceptor thresholds
• Innate immune cytokine responses (e.g., TNF-α, IL-6) and prostaglandin synthesis
• Serotonergic neurotransmission in the enteric nervous system
• Long-term adaptive immunity (antibody production)

Correct Answer: Innate immune cytokine responses (e.g., TNF-α, IL-6) and prostaglandin synthesis

Q19. Which parameter is critical when reporting analgesic or anti-inflammatory screening data to allow reproducibility?

• Only the final percent inhibition without time points
• Detailed description of animal species/strain, dose, route, time points and statistical methods
• Brand of laboratory gloves used
• Names of technicians but no methodological details

Correct Answer: Detailed description of animal species/strain, dose, route, time points and statistical methods

Q20. A selective COX-2 inhibitor would be expected to show which profile in screening assays?

• Strong inhibition of fever and late-phase inflammation with reduced gastric ulceration compared to nonselective NSAIDs
• No effect on prostaglandin levels but strong opioid-like analgesia
• Only central thermoregulatory effects without anti-inflammatory action
• Complete suppression of immune cell counts in blood

Correct Answer: Strong inhibition of fever and late-phase inflammation with reduced gastric ulceration compared to nonselective NSAIDs

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