**3. Mechanism of Action of onaBoNTA**

OnaBoNTA, a botulinumtoxinA with the most well-understood effects of therapy, is used in clinical settings. It is a neurotoxic protein that can bind its 100 kDa heavy chain to synaptic vesicle protein 2 as its protein receptor and enter the neuron endings; thereafter, its 50 kDa light chain is released, translocated to the cytosol [2,3]. The light chain of onaBoNTA cleaves synaptosomal nerve-associated protein (SNAP) 25, blocks soluble N-ethylmaleimide-sensitive fusion attachment protein receptor complex, and interferes with synaptic acetylcholine vesicle fusion to the cell membrane from presynaptic efferent nerves; thus, it causes paralysis of the detrusor muscle and modulation of the postsynaptic receptors. Furthermore, onaBoNTA intradetrusor injection possesses the ability to interrupt C-fibre sensory transmission, block the release of neurotransmitters (e.g., substance P, adenosine triphosphate, and calcitonin gene-related peptide), prevent receptor trafficking (TRPV1 as an example), and decrease ATP and nerve growth factor (NGF) releasing and affects preganglionic parasympathetic nerve terminals [11]. Due to its chemodenervation effects, onaBoNTA may provide anti-inflammation and antinociceptive effects for patients against neurogenic inflammation along with blocking the release of neuropeptides [3].
