The antibiotic that may accentuate the neuromuscular blockade produced by d-tubocurarine is

Correct Answer: C

Rationale: In this question, the correct answer is C) Streptomycin. Streptomycin is an aminoglycoside antibiotic that can potentiate the neuromuscular blockade produced by d-tubocurarine. This interaction occurs because aminoglycosides can interfere with neuromuscular transmission, leading to an accentuated effect when combined with d-tubocurarine, a neuromuscular blocking agent. Now, let's discuss why the other options are incorrect: A) Penicillin G: Penicillin G is not known to accentuate neuromuscular blockade produced by d-tubocurarine. It does not have a significant interaction with d-tubocurarine in this context. B) Erythromycin: Erythromycin is a macrolide antibiotic and does not have a significant impact on neuromuscular blockade produced by d-tubocurarine. D) Chloramphenicol: Chloramphenicol is not associated with accentuating neuromuscular blockade produced by d-tubocurarine. It does not interact in a way that enhances the effects of d-tubocurarine. Educational context: Understanding drug interactions is crucial in clinical practice to prevent adverse effects and ensure safe and effective patient care. Knowing which drugs can potentiate or inhibit the effects of others is essential for healthcare professionals when managing patients receiving multiple medications. This knowledge helps in making informed decisions and providing optimal treatment strategies.

Correct Answer: D

Rationale: Catecholamine O-methyltransferase (COMT) is an enzyme responsible for the breakdown of catecholamines such as dopamine, epinephrine, and norepinephrine. In the context of the question, COMT is found in various tissues in the body. The correct answer, option D, "None of the above," is correct because COMT is not limited to any single specific location listed in the options. Option A, "Adrenergic neurone," is incorrect because COMT can be found in adrenergic neurons where it plays a role in the metabolism of catecholamines. Option B, "Brain," is also incorrect because COMT is present in the brain where it participates in the degradation of neurotransmitters. Option C, "Kidney," is incorrect as well because COMT is also found in the kidneys, contributing to the breakdown of catecholamines in this organ. In an educational context, understanding the distribution and function of enzymes like COMT is crucial in pharmacology, especially when studying drugs that target the peripheral nervous system. Knowing where these enzymes are located helps in predicting how drugs may be metabolized and their potential effects on different tissues. This knowledge is essential for healthcare professionals in prescribing medications and managing patients with conditions affecting the peripheral nervous system.

Correct Answer: D

Rationale: Atropine is an antagonist to all types of muscarinic receptors (M1, M2, and M3). Muscarinic receptors are a subtype of acetylcholine receptors found in the peripheral nervous system. Atropine works by blocking these receptors, specifically inhibiting the actions of acetylcholine at these sites. Educationally, understanding the pharmacological action of atropine on muscarinic receptors is crucial for healthcare professionals, particularly those in fields like nursing, pharmacy, and medicine. Atropine is used in various clinical settings to treat bradycardia, organophosphate poisoning, and to dilate pupils during eye exams. Knowing that atropine acts on all muscarinic receptors helps healthcare providers predict its broad effects and potential side effects. Regarding the other options: - M1, M2, and M3 receptors are all valid targets for atropine, so options A, B, and C are incorrect. - By selecting option D, students demonstrate a comprehensive understanding of atropine's mechanism of action on muscarinic receptors, reinforcing the importance of this knowledge in clinical practice.

Correct Answer: B

Rationale: In this question about ß-adrenoceptor blockers and their lipid solubility, the correct answer is B) Atenolol. Atenolol is the least lipid-soluble among the options provided. This is because atenolol has a hydrophilic (water-loving) structure due to its polar side chain, which reduces its ability to penetrate lipid-rich cell membranes. To understand why the other options are incorrect: A) Propranolol is highly lipid-soluble due to its lipophilic side chain, allowing it to easily cross cell membranes. C) Oxprenolol and D) Metoprolol are also more lipid-soluble compared to atenolol, as they have structures that enhance their ability to pass through lipid barriers. Educational context: Understanding the lipid solubility of drugs is crucial in pharmacology as it impacts their distribution, metabolism, and ultimately their efficacy. Knowing the properties of different ß-adrenoceptor blockers can help healthcare professionals make informed decisions when selecting the most appropriate medication for a patient based on factors such as lipid solubility, pharmacokinetics, and therapeutic indications.

Correct Answer: D

Rationale: In the context of peripheral nervous system drugs, understanding the role of pseudo-cholinesterase is crucial. Pseudo-cholinesterase, also known as butyrylcholinesterase, is an enzyme responsible for metabolizing certain drugs and chemicals in the body. The correct answer, option D) Plasma and tissue, is where pseudo-cholinesterase is predominantly present. Plasma and tissue are the main locations where pseudo-cholinesterase functions to break down choline esters and certain drugs like succinylcholine. This enzyme plays a vital role in terminating the action of acetylcholine in the synaptic cleft and preventing excessive stimulation of cholinergic receptors. Options A) Membrane, B) Vesicles, and C) Synaptic cleft are incorrect because pseudo-cholinesterase is not primarily located in these areas. Understanding the specific localization of enzymes like pseudo-cholinesterase is essential in pharmacology to predict how drugs will be metabolized and their effects on the body. Educationally, grasping the distribution of enzymes like pseudo-cholinesterase enhances a student's ability to comprehend drug mechanisms, side effects, and potential drug interactions. It reinforces the importance of considering enzyme locations in pharmacokinetics and drug development.