BDNF and nicotine dependence: It is noteworthy that the putative human genes targeted by mistletoe miRNAs were also involved in several pathways associated with the nervous system, such as neurotrophin signaling pathway (ko04722), morphine addiction (ko05032), glutamatergic synapse (ko04724), GABAergic synapse (ko04727), axon guidance (ko04360), amphetamine addiction (ko05031) and nicotine addiction (ko05033).