This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuromuscular Blocker, Subject name: Anaesthesia
Phase I blocker is: 
Select and explain. 
A. Depolarization blockade, B. Desensitization blockade, C. Both, D. Neither
A: Depolarization blockade
Answer: A: Depolarization blockade 
Explanation: Phase I blockade is normal action of succinyl choline as depolarization neuromuscular blocker . Phase 2 blockade is is abnormal action of succinylcholine when given in repeated dose and is called desensitisation block. Due to repeated dose the nicotinic cholinergic receptor becomes desensitized by the effect of succinylcholine and now it cannot depolarize it.