Which of the following dopaminergic systems is most closely related to behavior?

Correct Answer: C

Rationale: The correct answer is C, the mesolimbic and mesofrontal systems, as they are directly involved in regulating behaviors related to motivation, reward, and decision-making. The mesolimbic system projects from the ventral tegmental area to the limbic system, influencing emotions and reinforcement. The mesofrontal system connects the prefrontal cortex to the ventral tegmental area, modulating executive functions and cognitive control of behavior. A: The hypothalamic-pituitary system primarily regulates hormone production and homeostasis, not behavior. B: The extrapyramidal system is involved in motor control and not directly linked to behavior. D: The chemoreceptor trigger zone of the medulla is related to vomiting reflex and not behavior.

Correct Answer: C

Rationale: The correct answer is C because nootropics are known for enhancing cognitive functions such as memory, focus, and creativity, not causing a decline in integrative brain functions. A: Selective influence is true as nootropics target specific brain areas. B: Improving communication aligns with nootropics enhancing cognitive abilities. D: Increased energetic exchange is a common effect of nootropics, boosting brain cell function.

Correct Answer: C

Rationale: Cocaine exerts its central action by inhibiting dopamine and norepinephrine reuptake. This leads to an accumulation of these neurotransmitters in the synaptic cleft, enhancing their effects. This mechanism results in increased stimulation of the central nervous system, leading to the characteristic effects of cocaine such as increased alertness and euphoria. Choices A and D are incorrect as cocaine does not directly affect phosphodiesterase or serotonin turnover. Choice B is incorrect as while cocaine does increase the release of neurotransmitters, its primary mechanism of action is through reuptake inhibition.

Correct Answer: D

Rationale: The correct answer is D: Trypsin. Trypsin is an enzyme that does not contain free sulfhydryl groups. A: Acetylcysteine contains a free sulfhydryl group, used as a mucolytic agent. B: Ambroxol contains a free sulfhydryl group, used as a mucolytic agent. C: Bromhexine contains a free sulfhydryl group, used as a mucolytic agent.

Correct Answer: C

Rationale: The correct answer is C: No-spa. No-spa is the drug that affects the biliary system and relaxes the Oddi sphincter. The Oddi sphincter is a muscular valve that controls the flow of bile and pancreatic juice into the duodenum. No-spa, also known as Drotaverine, is a smooth muscle relaxant that works by inhibiting phosphodiesterase enzyme, leading to relaxation of smooth muscles including the Oddi sphincter. Choices A, B, and D are incorrect as they do not specifically target the biliary system or the Oddi sphincter. Cholosas is a liver protectant, Oxaphenamide is a carbonic anhydrase inhibitor, and Cholenzyme is a combination of digestive enzymes.