Opiates have potent antidiarrheal actions that are mediated in part by delta-opioid receptors (DOR). We examined DOR localization within subregions of porcine ileum, a tissue analogous to human small bowel. A partial cDNA sequence for porcine DOR was obtained after reverse transcription-polymerase chain reaction cloning of forebrain RNA; it encoded the end of transmembrane domain 1 through the beginning of transmembrane domain 7 and exhibited 93% nucleotide identity with human DOR. Positive signals for DOR mRNA were found in all subregions of the porcine ileal wall. With an antiserum recognizing an N-terminal epitope in murine DOR, DOR-like immunoreactivity was localized in neurons within myenteric and submucous ganglia, longitudinal and circular smooth muscle, and villous lamina propria. The DOR agonist [D-Ser2, Leu5, Thr6]enkephalin (DSLET) attenuated circular smooth muscle contractions in porcine ileum that were evoked by electrical stimulation of myenteric cholinergic neurons. These results are consistent with previous reports of the DOR-mediated neuromodulation that underlies the antipropulsive and antisecretory effects of opioids in the intestinal tract.
|Original language||English (US)|
|Number of pages||9|
|Journal||Digestive Diseases and Sciences|
|State||Published - 1998|
Bibliographical noteFunding Information:
Supported in part by a University of Minnesota Graduate School Grant-in-Aid of Research # 16411 to D.R.B., and National Institutes on Drug Abuse grants DA-10200 to D.R.B.; DA-09643 to R.P.E., and DA-08010 to M.P.M. Support for S.P., M.A.O., and M.S.P. was provided by a RoyaThlaiGove rnme nt scholarship, Ne uroscience Training in Drug Abuse Research grant DA-07234 and Training in Psychone uroimmunology and Substance Abuse grant DA-07239, respectively.
- Host defense
- Opioid receptor
- Small intestine