The Role of Nerve Growth Factor in Alergic Reactions and Healing Process of Tissues

Nerve growth factor is a protein which regulates the differentiation and survival of nerve system. It is produced in neurons and in several non-nervous cells which are involved in some inflammatory and immunological states. These cells include mast cells, lymphocytes, macrophages and fibroblasts. Mast cells play a crucial role in the inflammatory and allergic reactions. Inflammatory cells express specific receptors for binding NGF, tyrosine kinase (TrkA) receptor. Binding of nerve growth factor to this receptor activates the immune cells. Activation of the cells leads to secretion of many inflammatory mediators from them. The mediators (histamine, serotonin, tryptase and some interlevkines) are involved in the early response of inflammatory cells. The cytokines and growth factors produced later in the inflammatory process activate fibroblasts and other cells, which participate in healing process of tissues.