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Abstract The neurotrophins are a family of neurotrophic factors whose actions influence neurons of the central nervous system (CNS). The best known neurotrophic factors include: nerve growth factor (NGF), fibroblast growth factor (FGF), ciliary neurotrophic factor (CNTF), brain derived neurotrophic factor (BDNF), neurotrophin 3 (NT-3), neurotrophin 4 (NT-4) which is now often termed neurotrophin 4/5 (NT-4/5), insulin-like growth factors (IGFs), vascular endothelial growth factor (VEGF), interleukins (ILs) and epidermal growth factor (EGF). Neurotrophins family consists of six members: NGF, BDNF, NT-3, NT-4/5, NT-6 and NT-7. Only four members of the neurotrophins are present in mammals: NGF, BDNF, NT-3 and NT-4/5. It is considered that neurotrophins are involved in the survival of CNS neurons and in experience dependent changes in the efficacy or strength of synaptic transmission in the CNS (synaptic plasticity). Neurotrophin receptors were originally thought to be expressed exclusively in neurons. However, it has been recognized that they are expressed in a variety of non neuronal cells e.g. fibroblasts, airway epithelial cells and immune cells. There are a number of experimental evidences indicating that neurotrophins levels may be altered by psychoactive drugs. The most common drugs studied in relation to neurotrophins were cannabis, nicotine, amphetamines, alcohol, cocaine and opioids. |