| Title | Galanin inhibits caerulein-stimulated pancreatic amylase secretion via cholinergic nerves and insulin. | | Author(s) | Barreto SG, Woods CM, Carati CJ, Schloithe AC, Jaya SR, Toouli J, Saccone GT | | Institution | Flinders University. | | Source | Am J Physiol Gastrointest Liver Physiol 2009 Jun 4. | | Abstract | Pancreatic exocrine secretion is affected by galanin, but the mechanisms involved are unclear. We aimed to determine the effect and elucidate the mechanism of action of exogenous galanin on basal and stimulated pancreatic amylase secretion in-vitro. The effect of galanin on basal and carbachol and caerulein-stimulated amylase secretion from isolated murine pancreatic lobules was measured. Carbachol and caerulein concentration-response relationships were established. Lobules were co-incubated with galanin (10(-12)M-10(-7)M), carbachol (10(-6)M) or caerulein (10(-10)M). Lobules were pre-incubated with atropine (10(-5)M), tetrodotoxin (10(-5)M), hexamethonium (10(-5)M), or diazoxide (10(-7)M and 10(-4)M) for 30mins followed by incubation with caerulein (10(-10)M) alone, or combined with galanin (10(-12)M). Amylase secretion was expressed as percent of total lobular amylase. Immunohistochemical studies used the antigen retrieval technique and antisera for galanin receptor (GALR) 1, 2 and 3. Carbachol and caerulein stimulated amylase secretion in a concentration-dependent manner with maximal responses of 2 and 1.7 fold over control evoked at 10(-6)M and 10-10M, respectively. Galanin (10(-12)M) completely inhibited caerulein-stimulated amylase secretion but had no effect on carbachol-stimulated or basal secretion. Atropine and tetrodotoxin pre-treatment abolished the caerulein-stimulated amylase secretion while hexamethonium had no significant effect. Diazoxide significantly reduced caerulein-stimulated amylase secretion by approximately 80%. Galanin did not affect caerulein-stimulated amylase secretion in the presence of hexamethonium or diazoxide. Glucose-stimulated amylase secretion was also inhibited by galanin. Immunohistochemistry revealed islet cells labeled for GALR2. These data suggest that galanin may modulate caerulein-stimulated amylase secretion by acting on cholinergic nerves and/or islet cells possibly via GALR2 to regulate insulin release Key words: pancreatic exocrine secretion, pancreatic lobules, insulin, cholinergic. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19497960 |
|
