Botulinum toxin acts by:

Ans.(b) Presynaptic inhibition of release of acetylcholineRef Katzung 10th ed. Ch 27* Botulinum toxin is a neuromascular blocking agent which act at neuromascular junction by blocking the presynaptic release of Ach vesicles.* Doing so, it reduces spasticity in a variety of neurologic conditions (ie, spasmolytics).* NOTE: Neuromuscular blocking drugs interfere with transmission at the neuromuscular end plate and lack central nervous system activity. Also KnowMOA of drugs and their siteDrugSite of ActionMoaLocal anestheticsNerve axonsBlock Na channelsHemicho- liniumAt cholinergic nerve terminalBlocks uptake of choline and slows synthesisVesamicolCholinergic terminal vesiclePrevents storage, depletesReserpineAdrenergic terminal vesiclePrevents storage, depletesTyramine, Ampheta- mineAdrenergic nerve terminalsPromote transmitter releaseBethanecholReceptors, parasympathetic effector cells (smooth muscle, glands)Binds and activates muscarinic receptorsAtropineReceptors, parasympathetic effector cellsBinds muscarinic receptors; prevents activatio