Motilin receptor expression in smooth muscle, myenteric plexus, and mucosa of human inflamed and noninflamed intestine.
BACKGROUND
Besides regulation of upper gastrointestinal motility, motilin seems to play a role in the inflammatory response. Motilin receptor expression in human intestine has not been studied thoroughly. This study aimed to describe the intestinal distribution of motilin receptors in inflammatory bowel disease (IBD) and control patients.


METHODS
Quantitative autoradiography, immunohistochemistry, and reverse-transcriptase polymerase chain reaction (RT-PCR) were used to detect motilin receptors in tissue of 25 IBD patients (13 Crohn's disease [CD], 12 ulcerative colitis [UC]) and 19 patients with a neoplasm (controls).


RESULTS
Median muscular motilin binding was 3 and 8 fmol/g tissue in colon and ileum, respectively. In the gastroduodenal region the median was higher (93 fmol/g). In UC colonic muscular motilin binding was significantly increased compared to controls (7 vs. 3 fmol/g, P < or = 0.05). Expression in CD was similar to controls. Besides the binding found in the muscular compartment, motilin binding was also found in the mucosa, which was even higher than in the muscle (3 versus 11 and 8 versus 27 fmol/g for colon and ileum (P < or = 0.06), respectively). RT-PCR and immunohistochemistry confirmed the mucosal motilin receptor expression. The mucosal motilin receptors were located in the epithelial cells. In the muscular compartment receptors were strongly present in the myenteric plexus and weakly in the smooth muscle cells. In IBD tissue the expression pattern was not different.


CONCLUSIONS
The motilin receptor is expressed in human colonic and ileal smooth muscle. Further, motilin receptor expression was also shown in the mucosa. Muscular binding in UC patients is increased but no different expression pattern was found.
Ter Beek
W Pascale
WP
Department of Gastroenterology-Hepatology, Leiden University Medical Centre, The Netherlands.
Muller
Eveline S M
ES
van den Berg
Marlies
M
Meijer
Martin J
MJ
Biemond
Izäk
I
Lamers
Cornelis B H W
CB
D000293:Adolescent; D000328:Adult; D000368:Aged; D001345:Autoradiography; D003106:Colon / Q000378:metabolism / Q000473:pathology; D005260:Female; D015870:Gene Expression / Q000235:genetics*; D006801:Humans; D007082:Ileum / Q000378:metabolism / Q000473:pathology; D007150:Immunohistochemistry; D015212:Inflammatory Bowel Diseases / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009130:Muscle, Smooth / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*; D011964:Receptors, Gastrointestinal Hormone / Q000096:biosynthesis / Q000235:genetics*; D018013:Receptors, Neuropeptide / Q000096:biosynthesis / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D012333:RNA, Messenger; D011964:Receptors, Gastrointestinal Hormone; D018013:Receptors, Neuropeptide; C050802:motilin receptor; D009195:Peroxidase