Effect of DS-4574, a novel peptidoleukotriene antagonist with mast cell stabilizing action, on acute gastric lesions and gastric secretion in rats

Antisecretory, antioxidative and antiapoptotic effects of montelukast on pyloric ligation and water immersion stress induced peptic ulcer in rat

In the present study, we tried to explore the mechanism of montelukast as an antiulcerogenic agent in pyloric ligation (PL) and water immersion stress (WIS) induced peptic ulcer. The ameliorative effects of montelukast (5, 10, and 20 mg/kg, p.o.) on gastric volume and total acidity were studied in PL model. We have investigated the alteration in the ulcerative index, thiobarbituric acid reactive substances, reduced glutathione, activity of myeloperoxidase, and total calcium level in both models. Estimation of DNA fragmentation by gel electrophoresis was also performed. Medium and higher doses of montelukast showed significant (p<0.05) ameliorative potential on all the above parameters as compared with omeprazole treated group. DNA fragmentation pattern clearly indicated the antiapoptotic effect of montelukast in preventing mucosal erosion in both models. Hence, the gastroprotective effect of montelukast may be attributed to its antisecretory, antioxidative along with its antiapoptotic effect.

Effects of the vasoactive intestinal peptide on stress-induced mucosal ulcers and modulation of methylation of histamine in gastric tissue of the rats

Vasoactive intestinal peptide (VIP) prevents stress-induced gastric ulcers, inhibits mast cell degranulation and protects gastric tissue from lipid peroxidation. Histamine has an important role in the development of gastric ulcers and mast cell derived histamine might be essential in this process.

The protective effect of vasoactive intestinal peptide (VIP) on stress-induced gastric ulceration in rats

The pathogenesis of cold-restraint stress ulcer involves various factors and is not completely understood. Mast cell degranulation, increased gastric muscular contractility, diminished mucosal blood flow, release of several biogenic amines, activated polymorphonuclear leukocytes, and lipid peroxidation which results from toxic oxygen molecules were suggested to be related to the production of gastric damage by cold-restraint stress. Recent evidence strongly indicates that VIP has a modulatory effect on tissue injury. Sprague-Dawley rats were used in two series of experiments. One set of rats was exposed to cold-restraint stress with some of the rats pretreated with VIP. The second set of rats was exposed to cold-restraint stress and then was administered VIP for different durations. Cold-restraint stress induced gastric lesions and mast cell degranulation and also increased lipid peroxidation in gastric tissue. VIP prevented stress-induced ulcers and mast cell degranulation and protected gastric tissue from lipid peroxidation. When VIP was used after induction of stress ulcer it was therapeutically beneficial. Thanks to its antioxidant and anti-inflammatory activity, VIP can be valuable in the prevention of gastric mucosal damage induced by cold-restraint stress.

Protective effect of DS-4574, a peptidoleukotriene receptor antagonist, against endotoxin-induced intestinal injury in rats

We evaluated the protective effect of DS-4574 (6-(2-cyclohexylethyl)-[1,3,4]thiadiazolo[3,2-a]-1,2,3- triazolo[4,5-d]pyrimidin-9(3H)-one), a peptidoleukotriene receptor antagonist, against intestinal mucosal injury evoked by endotoxin in rats by exploring changes in hematocrit and plasma leakage along with morphological features. Treatment with Escherichia coli endotoxin (5 mg/kg i.v.) alone elicited hemoconcentration, vasocongestion and a marked mucosal necrosis. DS-4574 (10-50 mg/kg) effectively prevented these changes on either oral or intraduodenal administration. These results demonstrate that peptidoleukotrienes may be key mediators in the intestinal injury induced by endotoxin in rats.

Radioimmunoassay for DS-4574, an antiallergic agent: development, evaluation, and application to human plasma samples

A sensitive radioimmunoassay (RIA) method for DS-4574, an antiallergic drug, in plasma has been developed. As the three major metabolites have a hydroxyl group on the cyclohexyl ring, the triazole ring in the terminal part of molecule was attached to ovalbumin with a spacer of beta-chloropropionic acid succinimido ester to prepare an immunogen. Anti-DS-4574 antisera was obtained in rabbits immunized with the immunogen emulsified in Freund's complete adjuvant. The detection limit of the present RIA method was 1 mg/mL of plasma, which was 100-fold more sensitive than the HPLC method developed previously. Cross-reactivities with three major metabolites were less than 3%. The precision of the assay based on triplicate samples showed intra- and inter-assay coefficients of variations of less than 5% and 4%, respectively. This RIA method was applied to plasma samples of six volunteers who had received a single oral 10 mg dose of DS-4574. Plasma concentrations increased rapidly and reached 60 ng/mL at 0.5 h after administration. The concentration decreased to near the detection limit at 4 h postdose. The present RIA method was shown to possess adequate sensitivity to evaluate pharmacokinetic properties of the drug for clinical study, which was not possible by the HPLC method.

Inhibitory effect of DS-4574, a mast cell stabilizer with peptidoleukotriene receptor antagonism, on gastric acid secretion in rats

We examined the inhibitory effect of DS-4574 (6-(2-cyclohexylethyl)[1,3,4]thiadiazolo[3,2-alpha]-1,2,3- triazolo[4,5-d] pyrimidin-9(3H)-one), a mast cell stabilizer with peptidoleukotriene receptor antagonism, on gastric acid secretion stimulated by several secretagogues in rats. In anesthetized rats with acute gastric fistulas, DS-4574 (50 mg/kg, intraduodenal) significantly inhibited gastric acid secretion induced by both carbachol (50 micrograms/kg, s.c.) and pentagastrin (75 micrograms/kg, s.c.) but not by histamine (2.5 mg/kg, s.c.). In unanesthetized pylorus-ligated rats, DS-4574 (10 and 25 mg/kg, intraduodenal) markedly suppressed increases in gastric acid output and histamine leakage into the gastric juice produced by carbachol (0.1 mg/kg, s.c.) or pentagastrin (1 mg/kg, s.c.). When the relationship between acid output and histamine leakage elicited by carbachol and pentagastrin was assessed, there was a close correlation (r = 0.84) that was highly significant (P < 0.01). In the in vitro study with rat gastric tissues, DS-4574 (10(-7)-10(-5) M) had no effect on the K(+)-dependent ATPase activity or on aminopyrine uptake into mucosal preparations containing parietal cells stimulated by carbachol (10(-5) M), histamine (10(-4) M), or dibutyryl-cyclic AMP (10(-3) M). These results suggest that the effect of DS-4574 may be mediated by inhibition of endogenous histamine from histamine-storing cells in the stomach.

Inhibitory effect of DS-4574, a peptidoleukotriene antagonist with mast cell stabilizing action, on compound 48/80-induced gastric mucosal lesions in rats

We evaluated the inhibitory effect of DS-4574, a peptidoleukotriene antagonist with mast cell stabilizing action, on rat gastric mucosal lesions induced by compound 48/80 (C48/80: a mast cell degranulator), in comparison with those of disodium cromoglycate (DSCG: a mast cell stabilizer), LY171883 (a peptidoleukotriene antagonist) and cimetidine (a histamine H2 receptor antagonist). Subcutaneous administration of C48/80 (1 mg/kg) once daily for four consecutive days produced extensive gastric lesions in the fundic mucosa. DS-4574 (20, 50 and 100 mg/kg/day, oral) and DSCG (200 mg/kg/day, intraperitoneal) treatment markedly inhibited formation of these mucosal lesions, but LY171883 (100 and 200 mg/kg/day, oral) and cimetidine (400 mg/kg/day, oral) treatment did not. Moreover, DS-4574 and DSCG significantly suppressed both hyperhistaminemia and histamine release from rat peritoneal mast cells induced by C48/80. These results indicate that the inhibitory effect of DS-4574 on gastric lesions induced by C48/80 may be related to its mast cell stabilizing action, but to neither its antisecretory nor its peptidoleukotriene antagonistic activity.

Antisecretory effect of DS-4574, a mast cell stabilizer with peptidoleukotriene antagonism, on gastric acid secretion in the pig

The antisecretory effect of DS-4574, a mast cell stabilizer with peptidoleukotriene antagonism, on the hypersecretion of gastric acid stimulated by several secretagogues was examined in the pig. Goettingen miniature pigs with chronic gastric fistula were used. Intramuscular injection of carbachol (60 micrograms/kg), tetragastrin (50 micrograms/kg) or histamine (200 micrograms/kg)-induced gastric acid hypersecretion. Intraduodenal administration of DS-4574 (10 and 20 mg/kg) significantly inhibited both the hypersecretion induced by carbachol and that by tetragastrin. On the other hand, DS-4574 (50 mg/kg, intraduodenal) did not suppress histamine-induced hypersecretion. In the in vitro study, no effect on hog gastric K(+)-dependent ATPase activity was found at concentrations of DS-4574 from 10(-7) to 10(-4) M. These results were highly similar to those in the rat. The suppression of histamine release from histamine-containing cells in the gastric mucosa of the rat was concluded to be an antisecretory effect of DS-4574.

Protective effect of DS-4574 on gastric mucosal injury induced by acidified ethanol in rats

We compared the protective effect of DS-4574, a peptidoleukotriene receptor antagonist with mast cell stabilizing action, on rat gastric mucosal injury induced by acidified ethanol to that of LY171883, a selective peptidoleukotriene receptor antagonist. Oral treatment with DS-4574 (1-10 mg/kg) or LY171883 (100 and 300 mg/kg) markedly suppressed this mucosal necrosis. Moreover, DS-4574 (10 mg/kg) significantly inhibited both mucosal edema and degranulation of mucosal mast cells. LY171883 (300 mg/kg) protected only from mucosal edema, but not degranulation of mucosal mast cells. These results suggest that DS-4574 possesses protective actions against gastric injury including the reduction of degranulation of mucosal mast cells, which are different from those of LY171883.