Which of the following agents is the precursor of dopamine?

Correct Answer: B

Rationale: Levodopa is the precursor of dopamine as it is converted into dopamine in the brain. Bromocriptine is a dopamine agonist, not a precursor. Selegiline is a MAO-B inhibitor that helps preserve dopamine, not a precursor. Amantadine is an antiviral drug with unclear mechanisms regarding dopamine production. Therefore, B is the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Tramadol. Tramadol is a mixed (opioid/non-opioid) agent as it acts on opioid receptors and inhibits the reuptake of serotonin and norepinephrine. This dual mechanism provides both opioid and non-opioid effects. Paracetamol (A) is a non-opioid analgesic, sodium valproate (C) is an anticonvulsant, and butorphanol (D) is a mixed opioid agonist-antagonist but not typically used as a tick mixed agent.

Correct Answer: A

Rationale: Rationale: MAO-A is more selective for depression because it primarily metabolizes serotonin and norepinephrine, neurotransmitters implicated in mood regulation. MAO-B mainly metabolizes dopamine. Choices B and C are incorrect because MAO-B is not as closely associated with depression, and MAO-C is a fictitious enzyme.

Correct Answer: D

Rationale: The correct answer is D. Camphor is not a respiratory or cardiac analeptic. Cordiamine, Bemegride, and Caffeine are all known to have stimulant effects on the respiratory and cardiac systems. Cordiamine and Bemegride specifically act as central nervous system stimulants, while Caffeine is a known respiratory and cardiac stimulant. Camphor, on the other hand, is commonly used in topical products for its cooling and soothing effects and does not have any direct stimulant effects on the respiratory or cardiac systems. Therefore, D is the correct answer as it does not belong to the category of respiratory and cardiac analeptics.

Correct Answer: C

Rationale: Rationale: Diazepam belongs to strong euphorizing agents due to its ability to produce feelings of euphoria and relaxation. It is a benzodiazepine with potent anxiolytic and sedative properties. Mebicarum (A) is an anxiolytic, not a strong euphorizer. Buspirone (B) is an anxiolytic without strong euphorizing effects. Chlordiazepoxide (D) is also a benzodiazepine but is not known for strong euphorizing properties.