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Proenkephalin A-derived peptides in the human gut
G L Ferri1, A Watkinson, G J Dockray
1Department of Anatomy, Tor Vergata University, Rome, Italy.
Gastroenterology
|October 1, 1988
Summary
This study mapped proenkephalin A-derived peptides in the human gastrointestinal tract. High concentrations of these enkephalins were found at the pyloric sphincter, suggesting a role in its function.
Area of Science:
- Neuroscience
- Gastroenterology
- Peptide Research
Background:
- Proenkephalin A is a precursor to various opioid peptides.
- Enkephalins play roles in pain modulation and gastrointestinal functions.
- The distribution of these peptides in the human GI tract is not fully understood.
Purpose of the Study:
- To investigate the intramural distribution of specific proenkephalin A-derived peptides throughout the human gastrointestinal tract.
- To correlate the levels of different enkephalin-related peptides.
- To elucidate the potential role of enkephalins in pyloric function.
Main Methods:
- Radioimmunoassay (RIA) for peptide quantification.
- Sephadex G-50 chromatography for peptide size separation.
- Reverse-phase high-performance liquid chromatography (RP-HPLC) for peptide identification.
Main Results:
- Parallel distribution of Leu5-enkephalin, Met5-enkephalin, Met5-enkephalin-Arg6-Phe7, and Met5-enkephalin-Arg6-Gly7-Leu8 was observed.
- High concentrations of these peptides were found in the submucosa and muscularis of the pyloric sphincter.
- Strong correlations were found between tissue levels of Leu5/Met5-enkephalin-like peptides and Met5-enkephalin-Arg6-Gly7-Leu8-like peptides (r=0.89), and between Met5-enkephalin-Arg6-Gly7-Leu8-like and Met5-enkephalin-Arg6-Phe7-like peptides (r=0.75).
Conclusions:
- The pyloric junction exhibits a rich enkephalin-containing innervation.
- Enkephalinergic mechanisms are likely involved in the control of pyloric function.
- Further research into the precise roles of these peptides in GI motility is warranted.