Vesicular Amine Transporter VMAT2 in the Rat Ileum: from Principal Mechanism to Clinical Applications

Besides the role of a classical neurotransmitter, histamine plays a key role in the immune/inflammatory processes in the gastrointestinal tract. Specific transport proteins pack the amine neurotransmitters into vesicles so that their release can be regulated by neural activity. Recently, two vesicular amine transporters (VMAT1 and VMAT2), essential components of monoaminergic neurons and endocrine cells were identified. In our study we investigated VMAT2 distribution in the rat distal ileum using an immunocytochemical technique. VMAT2- immunreactivity was found in neurons of the submucosal and myentericplexuses, as well as in a dense network of nerve fibers.VMAT2-containing varicosities were numerous in the circular muscle layer and around the blood vessels. Some fibers and nerve terminals were observed beneath the epithelial cells. This data provide important information about the amine-handling structures in the distal gut. Moreover, it raises the possibility for development of new pharmacotherapeutic approach to inflammatory bowel diseases.