cholecystokinin and Reperfusion-Injury

Melatonin, the main product of the pineal gland, is also released from the gastrointestinal endocrine-neurocrine (EE) cells. The concentrations of melatonin produced in the gut exceeds that originating from central nervous system. In spite of the presence of melatonin receptors in the pancreatic tissue little is known about the role of this indole in the pancreas. Our experimental studies have shown that exogenous melatonin, as well as this produced endogenously from its precursor; L-tryptophan, strongly stimulates pancreatic amylase secretion when given intraperitoneally, or into the gut lumen. This was accompanied by significant increases of CCK plasma level. Above pancreatostimulatory effects of luminal administration of melatonin, were completely reversed by bilateral vagotomy, capsaicin deactivation of sensory nerves or pretreatment of the rats with CCK1 receptor antagonist; tarazepide as well as serotonin antagonist; ketanserin. Melatonin, as well as its precursor; L-tryptophan, effectively protects the pancreas against the damage induced by caerulein overstimulation or ischemia/reperfusion. The beneficial effects of melatonin or L-tryptophan on acute pancreatitis could be related to the ability of melatonin to scavenge the free radicals, to activate antioxidative enzymes and to modulate the cytokine production.

Topics: Acute Disease; Amylases; Animals; Ceruletide; Cholecystokinin; Free Radical Scavengers; Gastrointestinal Tract; Melatonin; Pancreas; Pancreatitis; Receptor, Cholecystokinin A; Reperfusion Injury; Tryptophan

Cholecystokinin (CCK), as a gastrointestinal hormone, has an important protective role against sepsis or LPS-induced endotoxic shock. We aim to address the role of CCK in hepatic ischemia followed by reperfusion (I/R) injury.. A murine model of 60min partial hepatic ischemia followed by 6h of reperfusion was used in this study. CCK and CCKAR Levels in blood and liver were detected at 3h, 6h, 12h and 24h after reperfusion. Then the mice were treated with CCK or proglumide, a nonspecific CCK-receptor (CCK-R) antagonist. Mice were randomly divided into four groups as follows: (1) sham group, in which mice underwent sham operation and received saline; (2) I/R group, in which mice were subjected to hepatic I/R and received saline; (3) CCK group, in which mice were subjected to hepatic I/R and treated with CCK (400μg/kg); (4) proglumide group (Pro), in which mice underwent hepatic I/R and treated with proglumide (3mg/kg); CCK and proglumide were administrated via tail vein at the moment of reperfusion. Serum AST (sAST) and serum ALT (sALT) were determined with a biochemical assay and histological analysis were performed with hematoxylin-eosin (H&E). Cytokines (IL-1β, IL-6, IL-10, TNF-α) expressions in blood were determined with enzyme-linked immunosorbent assay (ELISA). The MPO (myeloperoxidase) assay were used to measure neutrophils' infiltration into the liver. The apoptotic index (TUNEL-positive cell number/total liver cell number×100%) was calculated to assess hepatocelluar apoptosis. Finally, activation of NF-κB and phosphor-p38 expression in liver homogenates were analyzed with Western Blot (WB).. Our findings showed that 1) CCK and CCK-AR were upregulated in our experimental model over time; 2) Treatment with CCK decreased sAST/sALT levels, inflammatory hepatic injury, neutrophil influx and hepatocelluar apoptosis, while proglumide aggravated hepatic injury.. These findings support our hypothesis and suggest that CCK played a positive role in the ongoing inflammatory process leading to liver I/R injury.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Cholecystokinin; Cytokines; Ischemia; Liver; Male; Mice, Inbred C57BL; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Peroxidase; Receptor, Cholecystokinin A; Receptor, Cholecystokinin B; Reperfusion Injury

The inhibitory effect of different reperfusion periods 45 min following hepatic ischemia on the expression of cholecystokinin (CCK) and vasoactive intestinal peptide (VIP) in the jejunum and the effect of salvia miltiorrhiza pretreatment were investigated, and the possible mechanism and implications were explored. Eighty rats were randomly divided into four groups: normal control group (CO group), sham-operated group (SO group), ischemia/reperfusion (I/R) injury group (IR group) and salvia miltiorrhiza pretreatment group (SM group). The rat model of I/R was established by using a non-invasive artery clamp to clip (45 min) or relax the hepatic pedicle. In the SM group, saline (40 mL/kg) and salvia miltiorrhiza injection (6 g/kg) were injected via the tail vein 30 min before clipping the hepatic pedicle. In the SO group only the porta hepatis was dissected after laparotomy without clamping the hepatic pedicle. At 0, 3, 12, 24 and 72 h post-reperfusion, respectively, upper jejunum samples were taken for immunohistochemistry of CCK and VIP. It was found that 0 h after I/R, the expression of CCK and VIP in the upper jejunum was upregulated. With prolongation of the reperfusion period, the expression of CCK and VIP was also increased, reached the peak at the 24th h, and gradually returned to the normal level at the 72nd h after reperfusion. The levels of both CCK and VIP in the SM group were lower than those in the IR group. It is suggested that the digestive tract congestion injury caused by liver ischemia can upregulate the expression of CCK and VIP in the jejunum following reperfusion. Salviae pretreatment can partly reduce the increased expression of CCK and VIP in the jejunum in the same period, which might contribute to the early recovery of gastrointestinal motility.

Topics: Animals; Cholecystokinin; Gastrointestinal Motility; Intestinal Mucosa; Jejunum; Liver; Liver Diseases; Phytotherapy; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Salvia miltiorrhiza; Vasoactive Intestinal Peptide

We investigated the effect of neurotensin and cholecystokinin (CCK) on intestinal microcirculation after ischemia-reperfusion.. Ischemia was induced in Wistar rats by occlusion of the superior mesenteric artery for 40 min. Ten minutes before reperfusion, infusion of either neurotensin or CCK was started. Afterwards, the microhemodynamics of the jejunum were examined by means of intravital microscopy.. Ischemia-reperfusion decreased functional capillary density from 873.4+/-18.1 to 362.5+/-8.3 cm(-1) and red blood cell velocity from 0.49+/-0.03 to 0.34+/-0.02 mm/s. Furthermore, leukocyte-endothelium interaction was increased. Neurotensin infusion significantly increased functional capillary density to 483.2+/-9.0 cm(-1) and red blood cell velocity to 0.69+/-0.01 mm/s in the mucosal capillaries compared with ischemic controls. Despite the amelioration of villus perfusion, the number of non-perfused villi significantly increased (11.8+/-3.6%) compared with ischemic controls. CCK infusion also resulted in a significant increase of functional capillary density (535.2+/-7.4 cm(-1)) and red blood cell velocity (0.67+/-0.01 mm/s). In contrast to neurotensin, the number of non-perfused villi was not increased (5.8+/-2.2%).. We conclude that neurotensin further aggravates perfusion inhomogeneity and stasis when administered during the ischemic period. In contrast, CCK has no negative influence on perfusion homogeneity after ischemia-reperfusion. It may be superior to neurotensin in the reconstitution of normal microvascular perfusion patterns after ischemia-reperfusion.

Topics: Analysis of Variance; Animals; Capillaries; Cholecystokinin; Female; Intestinal Mucosa; Jejunum; Microcirculation; Neurotensin; Rats; Rats, Wistar; Reperfusion Injury