The cellular targets of enteric motor neurones are gastrointestinal smooth muscle cells, interstitial cells of Cajal (ICC), motor neurones themselves, neuroendocrine cells, mucosal secretory and absorptive cells, secretory glands, blood vessels, and immune cells.1 The effects of motor neurones on smooth muscles, particularly the circular muscle cells and ICCs, are precise in timing whereas their effects on other targets may be somewhat diffuse and long lasting. The enteric motor neurones themselves are targets for intrinsic sensory neurones, enteric interneurones, motor neurones, axons of extrinsic primary afferents, vagal-sacral preganglionic neurones, sympathetic postganglionic neurones, and local and endocrine mediators.

The major physiological neurotransmitters of motor neurones are acetylcholine (ACh), adenosine triphosphate (ATP), tachykinins (substance P and neurokinin (NK) A), vasoactive intestinal peptide (VIP)-pituitary activating cyclic AMP peptide, and nitric oxide (NO).1 Release of neurotransmitter such …