Actions of Motilin on Gastrointestinal Motility and Plasma Immu.noreactive Motilin Concentration in Interdigestive and Postprandial States

Peripheral or Central Administration of Motilin Suppresses LH Release in Female Rats: A Novel Role for Motilin

“…Perhaps motilin‐induced suppression of LH secretion shares similar pathways to those mediating fasting‐or glucoprivation‐induced suppression. Motilin secretion from the upper digestive tract increases during fasting and decreases postprandially ( 21). Glucose administration reduces plasma motilin concentrations and disrupts its episodic pattern of release.…”

“…The vagus nerve is thought to mediate the stimulation of motilin release during fasting; plasma motilin concentrations are increased by electrical stimulation of the vagus accompanied by an increase in gastrointestinal myoelectric activity in the dog ( 27). Atropine attenuates both vagal stimulation‐induced increase in plasma motilin concentrations and episodic pattern of motilin release in fasted animals, resulting in decrease of the plasma concentrations of this peptide to baseline level ( 21). Our previous study revealed that fasting‐induced suppression of LH pulses is reversed by gastric vagotomy, suggesting that vagus nerve mediates the fasting‐induced suppression of LH release ( 28).…”

“…One candidate is motilin, which is a 22‐amino acid peptide found in the gastrointestinal tract, and is generally considered to be a gastric motor‐activity‐stimulating factor ( 18–20). Plasma motilin concentrations increase with a typically episodic secretory pattern at approximately 100‐min intervals during fasting in the dog, and feeding reduces the concentrations as well as abolishes the episodic secretory pattern ( 21). Among the nutrients, glucose was found to suppress motilin secretion in the dog and the human ( 22, 23).…”

Non‐nutritive sucking does not increase blood levels of gastrin, motilin, insulin and insulin‐like growth factor 1 in premature infants receiving enteral feedings

“…An increase in serum insulin concentrations after the first feeding was observed at 25 and 55 min in full-term infants receiving nipple or bolus nasogastric feedings (1 I , 12), but not in premature infants after either continuous or bolus nasogastric feedings (1 2). Motilin stimulates gastrointestinal motor activity, reducing small intestinal transit time (13,14). Motilin levels increased by 2.5 days of life in fed term infants and in premature infants receiving nasogastric feedings compared to premature infants receiving no enteral feedings (8).…”

Involvement of Serotonergic Mechanisms in the Disruption of Ovine Duodenal Migrating Myoelectric Complex Cycles by Duodenal Acidification

“…In man, their mediation relies on functional duode nal postganglionic cholinergic nerves [3], and in the cat, cholinergic pathways have been implicated [5], In the present investiga tion, premature RSAs induced by duodenal acidification were not blocked by 5-HT2 an tagonists, a finding which suggests the ab sence of a serotonergic pathway incorporat ing 5-HT2 receptors in the mediation of these premature RSAs. This is not surpris-ing, since premature duodenal RSAs may rely on peripheral dopaminergic receptors [15], opioid receptors and/or receptors which respond to motilin [16][17][18][19][20], Acidification of the duodenum with large quantities of HC1 not only induced prema ture RSAs but also elicited a transient inhibi tion of the contractions of the reticulum and a shortening of the duration of subsequent MMC cycles. This shortening of MMC cy cles may correspond to the reported disrup tion of the pattern of subsequent duodenal MMC, observed when the duodenum of con scious sheep was acidified with large acid loads [1], Since the shortening of the dura tion of MMC cycles did not occur in animals that were pretreated with the 5-HT2 antago nist ritanserin, which is a more selective 5-HT2 antagonist than metergoline, a seroton ergic mechanism incorporating 5-HT2 recep tors appears to be required in the mediation of the observed shortening of duodenal MMCs.…”