Intestinal motility Gastrointestinal function

Experiments carried out in the conscious rat demonstrated that H3 receptors contribute only to the central, and not the peripheral, regulation of intestinal motility (Fargeas et al., 1989). In addition, the concomitant ineffectiveness on acid secretion of peripherally administered H3 ligands seems to exclude a significant role of H3 receptors in the peripheral regulation of gastrointestinal functions. Lastly, in the mouse H3 receptors do not seem to have any appreaciable influence on gastrointestinal motility (Oishi et al., 1993)... 

If an organ is innervated by both the sympathetic and parasympathetic divisions, a physiologic antagonism typically exists between these divisions. That is, if both divisions innervate the tissue, one division usually increases function, whereas the other decreases activity. For instance, the sympathetics increase heart rate and stimulate cardiac output, whereas the parasympathetics cause bradycardia. However, it is incorrect to state that the sympathetics are always excitatory in nature and that the parasympathetics are always inhibitory. In tissues such as the gastrointestinal tract, the parasympathetics tend to increase intestinal motility and secretion, whereas the sympathetics slow down intestinal motility. The effect of each division on any tissue must be considered according to the particular organ or gland. 

Figure 6.4 Types of intestinal motility patterns. Segmentation, tonic contraction, and peristalsis are the three major types of motility patterns observed in the gut. Each serves a specific function for digestion and processing of luminal contents. From E.B. Chang, M.D.Sitrin and D.D.Black (1996) Gastrointestinal motility and neurophysiology. Gastrointestinal, Hepatobiliary, and Nutritional Physiology, Lippincott-Raven, Philadelphia, pp. 27-51...

Gastrointestinal motility is an essential function of the digestive and absorptive processes of the gut. It propels intestinal contents, mixes them with digestive juices, and prepares unabsorbed particles for excretion. Gastric motility has been shown to be inhibited by D-glucose in the intestinal fluid. 

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