Botulinum toxin causes muscle paralysis because
a. no acetylcholine enters the synaptic cleft
b. sodium is removed from the synaptic cleft
c. the acetylcholine receptors at the motor end-plate are blocked
d. calcium is removed from the neuromuscular junction

a. no acetylcholine enters the synaptic cleft.

Explanation:

The Botulinum toxin exerts its effects by targeting nerves that release acetycholine by degrading SNARE proteins which facilitate the binding and release of acetylcholine from vesicles into the synaptic cleft.

activation of phospholipase c (plc) indirectly increases intracellular ions through inositol triphosphate (ip3).

probably since the potency of the cocaine, not a lot, but i've never done any research on cocaine so i wouldn't know, but i would also guess it would determine on the gap between sniffs or if you did it all at once, so i really don't know.