Phosphatidic acid production, required for cholecystokinin octapeptide-stimulated amylase secretion from pancreatic acinar AR42J cells, is regulated by a wortmannin-sensitive process

Gastrin, cholecystokinin and gastrointestinal tract functions in mammals

The aim of the present review is to synthesise and summarise our recent knowledge on the involvement of cholecystokinin (CCK) and gastrin peptides and their receptors in the control of digestive functions and more generally their role in the field of nutrition in mammals. First, we examined the release of these peptides from the gut, focusing on their molecular forms, the factors regulating their release and the signalling pathways mediating their effects. Second, general physiological effects of CCK and gastrin peptides are described with regard to their specific receptors and the role of CCK on vagal mucosal afferent nerve activities. Local effects of CCK and gastrin in the gut are also reported, including gut development, gastrointestinal motility and control of pancreatic functions through vagal afferent pathways, including NO. Third, some examples of the intervention of the CCK and gastrin peptides are exposed in diseases, taking into account intervention of the classical receptor subtypes (CCK1 and CCK2 receptors) and their heterodimerisation as well as CCK-C receptor subtype. Finally, applications and future challenges are suggested in the nutritional field (performances) and in therapy with regards to the molecular forms or in relation with the type of receptor as well as new techniques to be utilised in detection or in therapy of disease. In conclusion, the present review underlines recent developments in this field: CCK and gastrin peptides and their receptors are the key factor of nutritional aspects; a better understanding of the mechanisms involved may increase the efficiency of the nutritional functions and the treatment of abnormalities under pathological conditions.

Complete loss of functional G protein-coupled receptors in mouse pancreatic acinar cell MPC-83

AIM: To study G-protein-coupled receptor (GPCR) in mouse exocrine pancreatic acinar cell line MPC-83.

METHODS: Cytoplasmic calcium concentration in mouse exocrine pancreatic acinar cell line MPC-83 was measured both before and after stimulation with GPCR agonists.

RESULTS: Acetylcholine (ACh, 25 nmol/L) and cholecystokinin (CCK, 5 pmol/L) induced regular calcium oscillations in freshly isolated normal mouse pancreatic acinar cells. When GPCR agonists CCK (1 μmol/L), vasopressin (VP, 1 μmol/L), substance P (5 μmol/L), histamine (10 μmol/L), phenylephrine (PE, 10 μmol/L) and ACh 100 μmol/L were added to MPC-83 cells, no change of intracellular calcium concentration was detected. After 100 nmol/L dexamethasone pre-treatment of MPC-83 cells for 72 h, MPC-83 cell proliferation was reduced, but still no calcium increases were detected after stimulation with GPCR agonists 1 μmol/L CCK, 1 μmol/L VP and 5 μmol/L substance P.

CONCLUSION: The pancreatic acinar tumor cell line MPC-83 from Kunming mice have completely lost their functional GPCR which are normally present in pancreatic acinar cells, and these cells are in extreme de-differentiation state.