Evidence for intrinsic regulation of met-enkephalin-immunoreactivity in gastroenteropancreatic tissues of the rat.
In a study whether gastrointestinal endogenous opioids can be modified by vagal denervation or by pharmacological application of an opiate, we examined met-enkephalin-immunoreactivity in gastrointestinal tissue in rats with and without truncal vagotomy and with and without subcutaneously implanted morphine pellets. The immunoreactivity of the tissue extracts gave dose-response lines in the radioimmunoassay for met-enkephalin which were near parallel to that for the standard. On Sephadex chromatography the met-enkephalin immunoreactivity eluted at a position similar to synthetic met-enkephalin. Tissue concentration of met-enkephalin immunoreactivity was not significantly different from the respective control after vagotomy and after morphine treatment. Total gastric met-enkephalin immunoreactive content increased significantly after vagotomy in line with gastric hypertrophy occurring after vagotomy without a drainage procedure. From these results it is concluded that met-enkephalin immunoreactivity in the rat gastrointestinal tract is regulated intrinsically, it is neither altered by vagal denervation nor by exogenous opiate administration.
D000818:Animals; D004064:Digestive System / Q000187:drug effects / Q000294:innervation / Q000378:metabolism*; D004744:Enkephalin, Methionine / Q000378:metabolism*; D009020:Morphine / Q000494:pharmacology; D010179:Pancreas / Q000187:drug effects / Q000294:innervation / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D014628:Vagotomy
D004744:Enkephalin, Methionine; D009020:Morphine