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Query: UMLS:C0406810 (NAME)
 13,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We examined the mechanism by which leminoprazole (an acid pump inhibitor) stimulates mucus synthesis in rats. Leminoprazole and omeprazole were administered to rats, and then the gastric fragments were isolated from the fundus of their stomachs. Mucus synthesis was assessed by [3H]leucine and [3H]glucosamine incorporation by the fragments into high-molecular-weight materials. After oral administration of leminoprazole, mucus synthesis by the gastric fragments was dose-dependently stimulated, while acid secretion was inhibited. Omeprazole had no effect on mucus synthesis, although it potently inhibited acid secretion. Treatment with NG-nitro-L-arginine methyl ester (L-NAME), but not indomethacin, caused a reduction of leminoprazole-stimulated synthesis of gastric mucus in a dose-dependent manner. The inhibitory action of L-NAME was restored by the concomitant administration of L-arginine, but not D-arginine. Intragastric administration of leminoprazole to pylorus-ligated rats also stimulated mucus synthesis without inhibiting acid secretion. In contrast, in the case of intraperitoneal administration, leminoprazole exerted a potent antisecretory effect, but failed to promote mucus synthesis. Exposure of leminoprazole to the luminal surface of the gastric mucosa did not cause any damage. We conclude that orally administered leminoprazole, via direct effect toward the gastric mucosa, stimulates mucus synthesis in rats probably through nitric oxide mediation. The stimulatory effect of leminoprazole on mucus synthesis is independent of its antisecretory effect.
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PMID:Mechanism by which orally administered leminoprazole stimulates mucus synthesis in rats. 967 Feb 12

The present experiments were designed to investigate the effects of omeprazole, a H(+)-K+ ATPase inhibitor, on corporal smooth muscle tone in vitro. All spontaneous contractile activity in the corpus cavernosum was blocked following omeprazole (0.1 mM-1 mM) administration. However atropine (1 microM), Nw-nitro L-arginine methyl ester (L-NAME, 30 microM) or indomethacin (10 microM) did not affect the spontaneous contraction. Omeprazole (10 microM-1 mM) concentration-dependently induced relaxation in corporal smooth muscle precontracted with 10 microM phenylephrine or 80 mM KCl. Pretreatment of corporal tissue with L-NAME (30 microM), indomethacin (10 microM), ammonium chloride (7.5 mM), sodium acetate (7.5 mM), tetraethyl ammonium chloride (0.5 mM) or glibenclamide (1 microM) had no effect on the omeprazole induced relaxant responses. Nimodipine, an L-type Ca++ channel blocker, relaxed corporal strips precontracted with 80 mM KCl. Collectively, these results indicate that the inhibition of spontaneous contraction and the relaxation of precontracted corporal smooth muscle by omeprazole is probably mediated by the blockade of calcium channels. Further work is needed to determine the cellular mechanism(s) of action by which omeprazole acts on corpus cavernosum smooth muscle.
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PMID:Evidence of relaxant effect of omeprazole in rabbit corpus cavernosum in vitro. 1121 Jul 16

The aim of the present study was to investigate the effect of omeprazole, an H+-K+-ATPase inhibitor, in myometrial smooth muscle strips from women undergoing elective caesarean section at term. Isolated myometrial strips taken with informed consent were obtained from eight pregnant women undergoing elective caesarean section at term (not in labour) and mounted in organ baths for recording of isometric tension. We recorded the effect of increasing concentrations of omeprazole on spontaneous and Ca2+-induced contractions of myometrial smooth muscle and on contractions of myometrial smooth muscle pretreated with indomethacin (3 x 10(-6) M) and L-NAME (3 x 10(-5) M). Omeprazole (10(-4)-10(-3) M) decreased the amplitude and frequency of spontaneous contractions in a time- and concentration-dependent manner in all myometrial smooth muscle isolated from pregnant women. The decrease in amplitude of contractions in myometrial smooth muscle reached statistical significance beginning from the concentration of 3 x 10(-4) M. Addition of indomethacin (3 x 10(-6) M) and L-NAME (3 x 10(-5) M) in to the organ baths 30 min before did not change relaxation responses to omeprazole. When 8 mM Ca2+-precontracted in Ca2+-free medium myometrial smooth muscle were exposed to increasing concentrations of omeprazole (10(-5)-10(-3) M), omeprazole produced relaxation responses in a time- and concentration-dependent manner, reaching statistical significance at 10(-4) M. These results show: (1) omeprazole time- and concentration-dependently decreased spontaneous contractile activity in myometrial smooth muscle isolated from pregnant women, (2) omeprazole-induced relaxations was not influenced by indomethacin and N(G)-nitro-L-arginine methyl ester (L-NAME), suggesting that it is not mediated by cyclooxygenase products and nitric oxide, and (3) omeprazole brought about time- and concentration-dependently relaxation of myometrial smooth muscle precontracted by 8 mM Ca2+ in Ca2+-free medium. This effect of omeprazole may be due to blockade of the calcium channels.
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PMID:Inhibitor effect of omeprazole in isolated human myometrial smooth muscle. 1145 34

We investigated the effect of omeprazole (1 x 10(-5)-3 x 10(-4)M), an inhibitor of H(+),K(+)-ATPase, on rat aortic rings pre-contracted with phenylephrine (10(-6)M). Omeprazole relaxed the tissue in a concentration-dependent manner. Either removal of the endothelium or incubation with nitric oxide (NO) synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME, 3 x 10(-5)M) significantly attenuated the relaxations. Pre-treatment with L-arginine (10(-3)M), but not with D-arginine, reversed the inhibitory action of L-NAME. Indomethacin (10(-6)M) and tetraethylammonium (TEA, 10(-2)M) did not affect the relaxant responses to omeprazole indicating the lack of involvement of cyclooxygenase products and K(+) channels, respectively. These results suggest a role of NO in the mechanism of action of omeprazole.
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PMID:Omeprazole-induced relaxation in rat aorta is partly dependent on endothelium. 1236 93

OBJECTIVE: To understand the role of nitric oxide in the protection mechanism for the gastric mucosa in rats provided by omeprazole. METHODS: Intravenous injections with omeprazole, N -nitro-L-arginine methyl ester (L-NAME), L-arginine, or D-arginine were administered in rats with gastric mucosal lesion induced by pure ethanol. Gastric mucosal blood flow (GMBF), pH of the gastric juice and gastric mucosal NO 2 /NO 3 ratio were determined and the changes of ulcer index and the severity of tissue necrosis and neutrophil infiltration observed. RESULTS: The ulcer index of rats with omeprazole treatment was much lower than that of the control group (P<0.01) with lesser degree of tissue necrosis and neutrophil infiltration (P<0.01). The protective effect of omeprazole was significantly inhibited by prior administration of L-NAME that, however, was antagonized by prior administration of L-arginine, but not D-arginine. Intravenous omeprazole administration obviously increased GMBF and gastric mucosal NO-2 /NO 3 ratio, and such effect, apart from its action against secretion, could be counteracted by pretreatment with L-NAME. CONCLUSION: Omeprazole can exert important protection against gastric mucosal lesion in rats mediated by nitric oxide, and the action of omeprazole against gastric acid secretion contributes little to the protective effect.
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PMID:Role of nitric oxide in omeprazole protection of the gastric mucosa in rats. 1242 68

Herein, we evaluated CYPs and their nuclear receptor mRNA induction by exposure to typical inducers, omeprazole, rifampicin, and phenobarbital in cynomolgus monkey hepatocytes. Six freshly-isolated hepatocytes and 6 cryopreserved hepatocytes from cynomolgus monkey liver were prepared for a 14-day monolayer culture, 28-day co-culture with feeder cells, and 28-day 3D spheroid culture with feeder cells. Omeprazole and rifampicin respectively induced CYP1A1 and CYP3A8 mRNAs, while phenobarbital induced CYP2C43, CYP2C75, and CYP3A8, and slightly induced CYP2B6. The nuclear receptors AHR, PXR, and CAR mRNA levels, which were activated by omeprazole, rifampicin, and phenobarbital, respectively, tended to decrease via exposure to inducers despite the increase in CYP mRNA levels. These trends were similar for all three culture methods. No evident difference was observed in CYP mRNA induction between fresh and cryopreserved hepatocytes. Based on mRNA levels, the co-culture and 3D spheroid culture methods are more reasonable than monolayer culture for CYP evaluation, because the use of feeder cells can reduce the number of hepatocytes, improve the cell adhesion, and maintain the mRNA expression levels. In addition, co-culture method is more cost-effective, as common culture plates can be used.
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PMID:Comparison of the inducibility of CYP mRNA exposed to typical inducers in fresh and cryopreserved cynomolgus monkey hepatocytes. 3230 57