Botulinum toxin treatments have lived together with cosmetic ingredients acting in the pre-synaptic or post-synaptic pathways to relax muscle contraction and improve fine lines.
Impulses from the central nervous system control skeletal muscle contraction via neuromuscular junctions (NMJs). Neurons receive chemical signals that produce changes in the membrane potential (depolarisation).
When depolarisation is large enough, it is converted into an action potential that spreads along the axons. Then, a Ca2+ influx triggers the fusion of secretory vesicles (filled with neurotransmitters) with the plasma membrane.