Abstract
BackgroundA significant percentage of patients with pancreatitis often presents a history of excessive alcohol consumption. Nevertheless, the patho-physiological effect of ethanol on pancreatitis remains poorly understood. In the present study, we have investigated the early effects of acute ethanol exposure on CCK-8-evoked Ca2+ signals in mouse pancreatic acinar cells. Changes in [Ca2+]i and ROS production were analyzed employing fluorescence techniques after loading cells with fura-2 or CM-H2DCFDA, respectively.ResultsEthanol, in the concentration range from 1 to 50 mM, evoked an oscillatory pattern in [Ca2+]i. In addition, ethanol evoked reactive oxygen species generation (ROS) production. Stimulation of cells with 1 nM or 20 pM CCK-8, respectively led to a transient change and oscillations in [Ca2+]i. In the presence of ethanol a transformation of 20 pM CCK-8-evoked physiological oscillations into a single transient increase in [Ca2+]i in the majority of cells was observed. Whereas, in response to 1 nM CCK-8, the total Ca2+ mobilization was significantly increased by ethanol pre-treatment. Preincubation of cells with 1 mM 4-MP, an inhibitor of alcohol dehydrogenase, or 10 μM of the antioxidant cinnamtannin B-1, reverted the effect of ethanol on total Ca2+ mobilization evoked by 1 nM CCK-8. Cinnamtannin B-1 blocked ethanol-evoked ROS production.Conclusionethanol may lead, either directly or through ROS generation, to an over stimulation of pancreatic acinar cells in response to CCK-8, resulting in a higher Ca2+ mobilization compared to normal conditions. The actions of ethanol on CCK-8-stimulation of cells create a situation potentially leading to Ca2+ overload, which is a common pathological precursor that mediates pancreatitis.
Highlights
A significant percentage of patients with pancreatitis often presents a history of excessive alcohol consumption
Effect of ethanol-induced reactive oxygen species generation (ROS) generation on CCK8-evoked changes in [cytosolic free Ca2+ concentration (Ca2+]i) In order to evaluate whether the effects of ethanol on [Ca2+]i are mediated by a secondary ROS generation, we investigated the changes in [Ca2+]i in the presence of the TcFeimgllsuer-ceo5urse of ROS production in mouse pancreatic acinar Time-course of ROS production in mouse pancreatic acinar cells
We have further investigated the possible mechanisms involved in the early effects of an acute ethanol exposure on cholecystokinin octapeptide (CCK-8)-evoked Ca2+ signals in mouse pancreatic acinar cells, because Ca2+ signalling is of critical importance for CCK-8-evoked responses in the exocrine pancreas
Summary
A significant percentage of patients with pancreatitis often presents a history of excessive alcohol consumption. We have investigated the early effects of acute ethanol exposure on CCK-8-evoked Ca2+ signals in mouse pancreatic acinar cells. Cholecystokinin stimulates the activity of pancreatic acinar cells via generation of different second messengers in the signal cascades [1]. A rise in [Ca2+]i is an important early signal by which physiological secretagogues elicit the release of digestive enzymes from pancreatic acinar cells, being the spatiotemporal pattern of agonist-induced Ca2+ signals of critical importance for exocytosis of enzymes [6]. Cholecystokinin is a major physiological regulator of secretion by the exocrine pancreas, an over stimulation can cause injury to the pancreas which may lead to dysfunction of the gland and even to activation of death signalling pathways involving caspases [7,8]
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