ABSTRACT
Pavlov and his colleagues had presented extensive evidence to suggest that the nervous system was a major factor in the regulation of gastrointestinal (GI) function. Motilin, neurotensin and somatostatin have also been demonstrated by radioimmunoassay techniques to be released into the systemic circulation. Neurotensin was detected serendipitously as the result of its vasoactive properties during the isolation of substance and somatostatin was detected in hypothalamic extracts as an “interfering” factor during attempts to isolate the growth hormone-releasing factor. Extensive investigations conducted in the last century established that the enteric nervous system was a unique entity. The presence of distinct histological features, the existence of complete reflex pathways within the enteric nervous system and the considerable autonomy of function exhibited by the GI tract led Langley to classify the autonomic nervous system into three divisions: the sympathetic, the parasympathetic and the enteric nervous systems.
