Aggregation of platelet is promoted by

Correct Answer: D

Rationale: Platelet aggregation is a complex process involving various mediators. Prostaglandins and thromboxane are both derived from arachidonic acid and play crucial roles. Thromboxane promotes platelet aggregation by stimulating vasoconstriction and platelet activation. Prostaglandins also contribute to platelet aggregation by enhancing thromboxane synthesis and promoting platelet adhesion. Prostacyclin, on the other hand, inhibits platelet aggregation by inducing vasodilation and inhibiting platelet activation. Therefore, the correct answer is D, as both prostaglandins and thromboxane promote platelet aggregation. Choices A, B, and C are incorrect as they do not capture the dual role of prostaglandins and thromboxane in platelet aggregation.

Correct Answer: B

Rationale: The correct answer is B: MAO inhibitors. Phenelzine and tranylcypromine are both monoamine oxidase inhibitors (MAOIs). MAOIs work by blocking the enzyme monoamine oxidase, which increases the levels of neurotransmitters such as serotonin, norepinephrine, and dopamine in the brain. This leads to an improvement in mood and alleviation of depressive symptoms. Tricyclic antidepressants (choice A) work by blocking the reuptake of neurotransmitters, 5-HT uptake inhibitors (choice C) specifically target serotonin reuptake, and atypical antidepressants (choice D) have various mechanisms of action different from MAOIs. Therefore, the correct choice is B as phenelzine and tranylcypromine are classified as MAO inhibitors.

Correct Answer: D

Rationale: The correct answer is D: Promotes GABA release. Gabapentin increases the release of GABA, an inhibitory neurotransmitter in the brain, which helps to reduce abnormal electrical activity and alleviate pain. This mechanism of action is different from choices A, B, and C, as Gabapentin does not bind to GABAA or GABAB receptors nor inhibit GABA destruction. It is important to understand the specific pharmacological actions of Gabapentin to grasp its therapeutic effects accurately.

Correct Answer: C

Rationale: Rationale: 1. Domperidone selectively blocks levodopa-induced vomiting by acting on peripheral dopamine receptors in the chemoreceptor trigger zone. 2. It does not cross the blood-brain barrier, hence does not interfere with levodopa's antiparkinsonian action. 3. Metoclopramide (A) can cross the blood-brain barrier and may diminish the therapeutic effects of levodopa. 4. Cisapride (B) is a prokinetic agent and does not have a specific antiemetic effect on levodopa-induced vomiting. 5. Ondansetron (D) is a serotonin receptor antagonist that targets different pathways and does not specifically address levodopa-induced vomiting.

Correct Answer: C

Rationale: The correct answer is C: Both Morphine and Codeine. Opioids like morphine and codeine act on opioid receptors in the brain and spinal cord to provide pain relief, suppress cough reflex, and slow down gut motility to relieve diarrhea. Morphine is a potent opioid used for moderate to severe pain, while codeine is a milder opioid often used for mild to moderate pain. Both drugs are known to provide relief for pain, cough, and diarrhea due to their shared pharmacological actions on the body. Therefore, the correct choice is C as both morphine and codeine are effective in providing symptomatic relief for pain, cough, and diarrhea. Choices A, B, and D are incorrect as they do not accurately reflect the pharmacological properties of opioids like morphine and codeine in providing relief for these specific symptoms.