Galanin inhibits glucagon-like peptide-1 secretion through pertussis toxin-sensitive G protein and ATP-dependent potassium channels in rat ileal L-cells.

The neuropeptide galanin is widely distributed in the gastrointestinal tract and exerts several inhibitory effects, especially on intestinal motility and on insulin release from pancreatic beta-cells. The presence of galanin fibres not only in the myenteric and submucosal plexus but also in the mucosa, prompted us to investigate the regulatory role of galanin, and its mechanism of action, on the secretion of the insulinotropic hormone glucagon-like peptide-1 (GLP-1). Rat ileal cells were dispersed through mechanical vibration followed by moderate exposure to hyaluronidase, DNase I and EDTA, and enriched for L-cells by counterflow elutriation.

[Secretion of peptide YY and truncated glucagon-like peptide 1 by isolated intestinal cells in rats].

In order to study the cellular mechanisms involved in peptide YY (PYY) and truncated glucagon-like peptide 1 (TGLP1) release, a model of rat intestinal cells dispersed with collagenase/EDTA and enriched for L-cells by counterflow elutriation was developed. Elutriation significantly increased in the harvested cells the concentration of PYY (828 +/- 97 vs 151 +/- 16 fmol/10(6) cells) and TGLP1 (1,094 +/- 109 vs 167 +/- 20 fmol/10(6) cells), and brought the contribution of L-cells to 4-5% of the total cell population. Forskolin (1-10 microM) and dibutyryl cyclic AMP (dbcAMP, 1-5 mM) increased over an 1-h period PYY and TGLP1 secretion, with a maximal rate at 5 microM forskolin (232% and 250% of basal, respectively) and at 5 mM dbcAMP (347% and 234% of basal, respectively).