The principal mechanism of MAO inhibitor action is:

Correct Answer: B

Rationale: The correct answer is B: Blocking a major degradative pathway for the amine neurotransmitters, which permits more amines to accumulate in presynaptic stores. MAO inhibitors work by blocking the enzyme monoamine oxidase, which is responsible for breaking down neurotransmitters like serotonin, dopamine, and norepinephrine. By inhibiting this enzyme, MAO inhibitors allow these neurotransmitters to accumulate in the synaptic cleft, leading to increased neurotransmission. A: Blocking the amine reuptake pumps is the mechanism of action for tricyclic antidepressants, not MAO inhibitors. C: Inhibiting the storage of amine neurotransmitters in vesicles is not a known mechanism of action for MAO inhibitors. D: Antagonism of alpha2-norepinephrine receptors is the mechanism of action for alpha2-adrenergic receptor antagonists, not MAO inhibitors.

Correct Answer: A

Rationale: The correct answer is A because tranquilizers typically produce euphoria, burst of energy, increase in motor activity, and a warm sensation throughout the body. This is due to the sedative effects of tranquilizers, which can initially induce feelings of relaxation and well-being. Choice B is incorrect because visual hallucinations and distorted perception of time and space are more commonly associated with hallucinogens rather than tranquilizers. Choice C is incorrect because physical bliss, body lightness, a wish to fly, and motionlessness are not typical effects of tranquilizer intoxication. Choice D is incorrect because synaesthesia, where senses mix and one sensory experience triggers another, is not a common effect of tranquilizers intoxication. In summary, choice A is the correct answer as it aligns with the typical features of tranquilizers intoxication, while the other choices do not accurately describe the effects of tranquilizers.

Correct Answer: C

Rationale: Step 1: Identify the antitussive agents that have a peripheral effect. Step 2: Understand that antitussive agents with a peripheral effect act outside the central nervous system. Step 3: Recognize that Libexine is the only antitussive agent among the choices that exerts its effect peripherally. Step 4: Codeine and Tusuprex primarily act centrally, not peripherally. Step 5: Glaucine hydrochloride is a smooth muscle relaxant and not typically classified as an antitussive agent with a peripheral effect.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Cholosas is a bile stimulant of vegetable origin, containing bile salts. 2. Bile salts in Cholosas promote the production of bile in the liver, aiding in digestion. 3. Oxaphenamide and Papaverine are not bile stimulants. 4. Cholenzyme is an enzyme supplement, not a bile stimulant. In summary, Cholosas is the correct answer as it directly stimulates bile production, while the other choices are not related to bile production.

Correct Answer: D

Rationale: The correct answer is D because glycosides intoxication can lead to a range of cardiac manifestations, including atrioventricular junctional rhythm, second-degree atrioventricular blockade, and ventricular tachycardia. These effects are due to the toxic effects of glycosides on the heart's electrical conduction system. Atrioventricular junctional rhythm occurs when the impulse originates in the atrioventricular node, leading to a slower heart rate. Second-degree atrioventricular blockade involves a delay or interruption in the electrical signals between the atria and ventricles. Ventricular tachycardia is a rapid heart rhythm originating in the ventricles. Therefore, all of the above options are correct manifestations of glycosides intoxication.