Sympathetic stimulation is mediated by:

Correct Answer: D

Rationale: Sympathetic stimulation involves the activation of the sympathetic nervous system. Norepinephrine is released from sympathetic nerve terminals, activating adrenoreceptors on postsynaptic sites. Additionally, the adrenal medulla releases epinephrine into the bloodstream. Therefore, all three choices (A, B, and C) are mechanisms through which sympathetic stimulation is mediated. Hence, the correct answer is D. The other choices (A, B, and C) are incorrect as they individually represent different aspects of sympathetic stimulation, but the correct answer encompasses all of them.

Correct Answer: C

Rationale: The correct answer is C: Reserpine. Reserpine is a rauwolfia alkaloid acting as an adrenoreceptor antagonist by inhibiting the storage of norepinephrine and serotonin in vesicles. Prazosin (A) is an alpha-1 adrenergic receptor antagonist, Propranolol (B) is a non-selective beta-adre, Phentolamine (D) is a non-selective alpha-adrenergic receptor antagonist, making them all incorrect choices.

Correct Answer: D

Rationale: The correct answer is D. Antiseizure drugs work through multiple mechanisms to prevent seizures. 1. A: Antiseizure drugs enhance GABAergic transmission, increasing inhibition in the brain. 2. B: They also diminish excitatory glutamatergic transmission, reducing neuronal excitation. 3. C: Antiseizure drugs modify ionic conductance to stabilize neuronal activity. Therefore, the correct answer is D, as antiseizure drugs act through all the mentioned mechanisms to prevent seizures effectively. Choices A, B, and C are incorrect because they do not encompass the comprehensive range of mechanisms involved in the action of antiseizure drugs.

Correct Answer: C

Rationale: The correct answer is C: Dopamine. Parkinson's disease is characterized by a loss of dopamine-producing neurons in the brain. Dopamine is crucial for controlling movement and coordination, and its deficiency leads to symptoms of Parkinson's. Acetylcholine (Choice A) is not primarily involved in Parkinson's disease, and excess glutamate (Choice B) can actually be harmful in neurodegenerative disorders. Choice D is incorrect as acetylcholine and glutamate are not directly related to Parkinson's disease.

Correct Answer: C

Rationale: The correct answer is C: Fentanyl. Fentanyl is used in combination with droperidol in neuroleptanalgesia due to its fast onset of action and potent analgesic effects, making it an ideal choice for sedation and analgesia during procedures. Morphine (choice A) is not typically used in neuroleptanalgesia due to its slower onset of action and shorter duration. Buprenorphine (choice B) is a partial opioid agonist and is not commonly used in neuroleptanalgesia. Lastly, the duplicate choice D (Morphine) is incorrect for the same reasons mentioned earlier. In summary, Fentanyl is the preferred choice for neuroleptanalgesia due to its rapid onset and potent analgesic properties compared to the other options.