GABA as an autonomic neurotransmitter: studies on intrinsic GABAergic neurons in the myenteric plexus of the gut

Outside the CNS, no part of the nervous system approaches the structural and functional complexity of the enteric ganglia of the gastrointestinal tract. Recently, it has become evident that there is a population of GABAergic neurons within the myenteric ganglia in the stomach, duodenum, ileum, colon and caecum. The GABAergic neurons of the gut nervous system project not only to other neurons within the myenteric ganglia, but also out into the circular muscle coat of the gut wall. Their presence has important implications for the intrinsic neuronal control of gastrointestinal function.