ABSTRACT
This chapter attempts to estimate the possible role of various neuropeptides and peptide hormones for the physiological and pathophysiological function of gut motility. The occurrence of several peptides in endocrine cells and in enteric neurons changed the rather strict concept of hormones and neurotransmitters because it could be speculated that the same substance might act as a hormone and, when released from another site, might also act as a neurotransmitter. A physiological action on gastrointestinal motility must involve a process which can occur under normal conditions in the control of gut motor function. Peptides or hormones which mediate or modulate this function under normal conditions can be regarded as physiological transmitters or messengers. Differences of the peptides sequences might be present either due to species differences or due to various molecular forms produced by different molecular processing. Different molecular forms present within one species also can be caused by other posttranslational processing mechanisms.
