TY - JOUR T1 - Chapter 4—Summary JF - Gut JO - Gut SP - iv52 LP - iv52 DO - 10.1136/gut.47.suppl_4.iv52 VL - 47 IS - suppl 4 A2 - , Y1 - 2000/12/01 UR - http://gut.bmj.com/content/47/suppl_4/iv52.abstract N2 - Chapter 4 explores research into the structure and functional role of various cell types in the tissue surrounding enteric nerves. The cellular targets of enteric neurones include gastrointestinal smooth muscle, interstitial cells of Cajal (ICCs), neuroendocrine cells, mucosal secretory and absorptive cells, secretory glands, blood vessels, and immune cells. The variety of receptor types found on these various cells provides considerable scope for pharmacological intervention. In defining or identifying receptor types, however, attention has been drawn to the differences between the action of endogenous transmitters and those that are applied exogenously. It is important to be aware that pharmacological blockade of some pathways can lead to compensatory activity from parallel pathways, which also complicates the definition of receptor types. Regional differences may be found in different tissue layers and different parts of the same tissue layer. There are also differences between different parts of the gastrointestinal tract and between species. With these provisions in mind, data have been presented for specific tissue/organ systems.Studies of opossum oesophageal smooth muscle indicate that the main excitatory motor pathway to the smooth muscle cells involves acetylcholine and tachykinin, while the … ER -