Which of the following best describes the mechanism of action of d-Tubocurarine?
Correct Answer: Competitive, non-depolarising block at Nm cholinergic receptors
Description: D-tubocurarine is the prototype Non-depolarising neuromuscular blocking agents that causes a Competitive, non-depolarising block at Nicotinic (Nm) cholinergic receptors. Mechanism of Action of d-Tubocurarine and other Non-Depolarising Competitive Blockers: At low doses (Competitive Block) At high doses (Complete Blockage) At low doses (typical doses) Non-depolarising agents competitively block ACh at the nicotinic receptors. They compete with ACh at the receptor without stimulating it. Thus, these drugs prevent depolarization of the muscle cell membrane and inhibit muscular contraction. At high doses (Atypical doses) Non depolarising agents can also block the ion channels of the motor endplate Their competitive action can be overcome by administration of cholinestrase inhibitors, such as neostigmine and edrophonium, which increase the concentration of ACh in the neuromuscular junction At high doses with blockage of ion channels the abiility of ACh-esterase inhibitors to reverse the action is significantly reduced. At low doses, the muscle will respond to direct electrical stimulation from a peripheral nerve stimulator to varying degrees. This allows for monitoring of the extent of neuromuscular blockade With complete blockade, the muscle does not respond to direct electrical stimulation from a peripheral nerve stimulator Doesnot allow monitoring Ref: KDT 7th edition Pgno: 347
Category:
Pharmacology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now