Rate limiting step in cholinergic transmission ?: (A) Synthesis of acetylcholine from choline, (B) Active uptake of choline in axons, (C) Active uptake of acetylcholine by synaptic vesicle, (D) Release of acetylcholine from synaptic vesicle
Answer is B. Ans. is'b'i.e., Active uptake of choline in axonsAcetylcholine synthesis and releaseCholine is actively taken up by the axonal membrane by Na*; choline cotranspoer. (Rate limiting step). This step is blocked by Hemicholinium.