Parkinsonian symptoms and tardive dyskinesia are caused by blockade of dopamine in:

Correct Answer: A

Rationale: The correct answer is A: The nigrostriatal system. Parkinsonian symptoms and tardive dyskinesia are caused by dopamine blockade in the nigrostriatal system, which is responsible for motor control. Dopamine blockade here leads to movement disorders. Choices B, C, and D are incorrect because tardive dyskinesia and Parkinsonian symptoms are not primarily related to dopamine blockade in the mesolimbic and mesofrontal systems (B), chemoreceptor trigger zone of the medulla (C), or the tuberoinfundibular system (D). These systems are associated with other functions such as reward processing, nausea/vomiting regulation, and hormone release, respectively.

Correct Answer: D

Rationale: The correct answer is D: It has a high potential of toxicity. Piracetam is known for its low toxicity and safety profile, making it a popular nootropic. A: It is not a GABA derivative, but it does modulate some GABA receptors. B: It does influence neuro-vegetative functions positively. C: Improvement with piracetam typically starts earlier, around the 2nd week, rather than the 3rd week as mentioned in the incorrect choice.

Correct Answer: D

Rationale: The correct answer is D because cocaine intoxication presents with a variety of symptoms including clouding of consciousness, lightness of body, feeling of flight, wave warmth, physical bliss, motionlessness, clear consciousness, improved mood, influx of physical and spiritual forces, locomotive and speech excitation, and reappraisal of personality. These symptoms collectively represent the typical effects of cocaine intoxication. Choices A, B, and C each only describe a subset of the symptoms and experiences associated with cocaine intoxication, whereas choice D encompasses all the possible manifestations. Therefore, the correct answer is D as it includes all the symptoms that can be observed during cocaine intoxication.

Correct Answer: C

Rationale: The correct answer is C: Desoxiribonuclease. Desoxiribonuclease is an enzyme that breaks down DNA, not disulfide bonds of proteoglycans. A: Acetylcysteine breaks disulfide bonds, reducing sputum viscosity. B: Ambroxol disrupts disulfide bonds, aiding in sputum clearance. D: Bromhexin also works by disrupting disulfide bonds, facilitating mucus clearance.

Correct Answer: A

Rationale: The correct answer is A: Radioactive phosphorus 32. Radioactive phosphorus 32 depresses erythrogenesis by inhibiting DNA synthesis in rapidly dividing cells like erythroblasts. Ferrous sulfate (B) is an iron supplement that promotes erythropoiesis. Molgramostim (C) is a granulocyte-macrophage colony-stimulating factor, which stimulates white blood cell production, not erythrogenesis. Folic acid (D) is essential for DNA synthesis and red blood cell production, so it would not depress erythrogenesis.