Protective Effects of Cinnamic Acid Derivatives on Gastric Lesion

P-methoxycinnamic acid and 3,4,5-trimethoxycinnamic acid are the compounds found in Polygalae Radix, the root of Polygala tenuifolia Willdenow, and have been reported to have hepatoprotective and anti-neurodegenerative effects. On the other hand, there are no reports of their effects on gastric lesions. This study examined the inhibitory effects of cinnamic acids, including p-methoxycinnamic acid, 3,4,5-trimethoxycinnamic acid, and 8 compounds (cinnamic acid, 2-(trifluoromethyl) cinnamic acid, 3-(trifluoromethyl) cinnamic acid, trans-4-(trifluoromethyl) cinnamic acid, 4-(dimethylamino) cinnamic acid, 3,4-(methylenedioxy) cinnamic acid and 3,4-dihydroxycinnamic acid), which were selected based on their presence in medicinal herbs and molecular weight, against gastric lesions. Animal models were used to confirm the protective effects on acute gastritis caused by the administration of HCl/EtOH. Gastric acid inhibition was examined by an acid-neutralizing test and the proton pump (H⁺/K⁺-ATPase) inhibiting activity. In addition, antioxidant tests were performed and the gastric emptying rate was determined. The results showed that cinnamic acid, p-methoxycinnamic acid, and 3,4,5-trimethoxycinnamic acid had an inhibitory effect on gastric lesions.

Effects of dimethyltin chloride on renal H~+K~+-ATPase and Na~+K~+-ATPase activity in rats / 中国职业医学

OBJECTIVE: To study the effects of dimethyltin chloride( DMT) on the activity of renal H~+K~+-ATPase( HKA)and Na~+K~+-ATPase( NKA) in SD rats. METHODS: i) In vitro experiment. Five specific pathogen free( SPF) healthy female SD rats were used. The kidney homogenates made with 0. 90% sodium chloride solution was added with DMT( mass concentration,1. 0 g/L) to make final concentrations of 0,1,25,125 and 625 mg/L respectively,then the HKA and NKA activities were detected by the enzyme-linked immunosorbent assay( ELISA). ii) In vivo experiment. Forty SPF healthy SD rats were divided into control group and exposure group,with 20 rats( 10 males and 10 females) in each group. The exposure group was given one-time intraperitoneal injection with DMT( 16. 000 mg / kg body weight),while the control group was given one-time intraperitoneal injection with same volume of 0. 90% sodium chloride solution. The rats were executed 1 and 24 hours after exposure. The kidney tissue was extracted to make kidney homogenates for determination of HKA and NKA activity by microplate reader. The blood from abdominal aorta was collected to measure the levels of serum K~+,Na~+and Cl-. RESULTS: i) In vitro experiment. The HKA activity was inhibited by DMT,and the effect of inhibition increased with the increase of DMT exposure dose( P < 0. 01),showing a dose-effect relationship. The DMT had no effect on NKA activity( P > 0. 05). ii) In vivo experiment. The body weight of rats at 24 hours time point in exposed group was lower than that in control group( P < 0. 01). The HKA activity of the kidney tissue in rats in exposed group was lower than that of control group( P < 0. 01). The NKA activity in kidney tissue of rats and the level serum K~+,Na~+and Cl-did not show statistical difference in main and interactive effects concerning treatment and exposure time( P > 0. 05). CONCLUSION: DMT could inhibit the HKA activity in kidney homogenates,but had no obvious effect on NKA activity.

Potassium Channelopathies and Gastrointestinal Ulceration

Potassium channels and transporters maintain potassium homeostasis and play significant roles in several different biological actions via potassium ion regulation. In previous decades, the key revelations that potassium channels and transporters are involved in the production of gastric acid and the regulation of secretion in the stomach have been recognized. Drugs used to treat peptic ulceration are often potassium transporter inhibitors. It has also been reported that potassium channels are involved in ulcerative colitis. Direct toxicity to the intestines from nonsteroidal anti-inflammatory drugs has been associated with altered potassium channel activities. Several reports have indicated that the long-term use of the antianginal drug Nicorandil, an adenosine triphosphate-sensitive potassium channel opener, increases the chances of ulceration and perforation from the oral to anal regions throughout the gastrointestinal (GI) tract. Several of these drug features provide further insights into the role of potassium channels in the occurrence of ulceration in the GI tract. The purpose of this review is to investigate whether potassium channelopathies are involved in the mechanisms responsible for ulceration that occurs throughout the GI tract.

Potassium Channelopathies and Gastrointestinal Ulceration

Potassium channels and transporters maintain potassium homeostasis and play significant roles in several different biological actions via potassium ion regulation. In previous decades, the key revelations that potassium channels and transporters are involved in the production of gastric acid and the regulation of secretion in the stomach have been recognized. Drugs used to treat peptic ulceration are often potassium transporter inhibitors. It has also been reported that potassium channels are involved in ulcerative colitis. Direct toxicity to the intestines from nonsteroidal anti-inflammatory drugs has been associated with altered potassium channel activities. Several reports have indicated that the long-term use of the antianginal drug Nicorandil, an adenosine triphosphate-sensitive potassium channel opener, increases the chances of ulceration and perforation from the oral to anal regions throughout the gastrointestinal (GI) tract. Several of these drug features provide further insights into the role of potassium channels in the occurrence of ulceration in the GI tract. The purpose of this review is to investigate whether potassium channelopathies are involved in the mechanisms responsible for ulceration that occurs throughout the GI tract.

Protective Effect of Liriodendrin Isolated from Kalopanax pictus against Gastric Injury

In this study, we investigated the inhibitory activities on gastritis and gastric ulcer using liriodendrin which is a constituent isolated from Kalopanax pictus. To elucidate its abilities to prevent gastric injury, we measured the quantity of prostaglandin E2 (PGE2) as the protective factor, and we assessed inhibition of activities related to excessive gastric acid be notorious for aggressive factor and inhibition of Helicobacter pylori (H. pylori) colonization known as a cause of chronic gastritis, gastric ulcer, and gastric cancer. Liriodendrin exhibited higher PGE2 level than rebamipide used as a positive control group at the dose of 500 microM. It was also exhibited acid-neutralizing capacity (10.3%) and H+/K+-ATPase inhibition of 42.6% (500 microM). In pylorus-ligated rats, liriodendrin showed lower volume of gastric juice (4.38 +/- 2.14 ml), slightly higher pH (1.53 +/- 0.41), and smaller total acid output (0.47 +/- 0.3 mEq/4 hrs) than the control group. Furthermore liriodendrin inhibited colonization of H. pylori effectively. In vivo test, liriodendrin significantly inhibited both of HCl/EtOH-induced gastritis (46.9 %) and indomethacin-induced gastric ulcer (46.1%). From these results, we suggest that liriodendrin could be utilized for the treatment and/or protection of gastritis and gastric ulcer.

Gastroprotective Activities of Sennoside A and Sennoside B via the Up-Regulation of Prostaglandin E2 and the Inhibition of H+/K+-ATPase

Sennoside A (erythro) and sennoside B (threo) are dianthrone glycosides and diastereomers. We investigated their abilities to prevent the gastric lesions associated with diseases, such as, gastritis and gastric ulcer. To elucidate their gastroprotective effects, the inhibitions of HCl*EtOH-induced gastritis and indomethacin-induced gastric ulcers were assessed in rats. It was observed that both sennoside A and sennoside B increased prostaglandin E2 (PGE2) levels and inhibited H+/K+-ATPase (proton pump). In a rat model, both compounds reduced gastric juice, total acidity and increased pH, indicating that proton pump inhibition reduces gastric acid secretion. Furthermore, sennoside A and B increased PGE2 in a concentration-dependent manner. In a gastric emptying and intestinal transporting rate experiment, both sennoside A and sennoside B accelerated motility. Our results thus suggest that sennoside A and sennoside B possess significant gastroprotective activities and they might be useful for the treatment of gastric disease.

Inibidores da bomba protônica / Proton pump inhibitors

O uso dos inibidores da bomba protônica (IBPs) no tratamento da doença do refluxo gastroesofágico (DRGE) está bem estabelecido. Esta classe de medicamentos está indicada como primeira linha de tratamento para aliviar os sintomas e/ou cicatrizar as lesões esofágicas, sobretudo em pacientes com doença moderada a grave. Estudos randomizados e controlados têm demonstrado que os IBPs são mais eficazes que os antagonistas do receptores H2 no controle da supressão ácida do estômago. A secreção ácida nas células parietais do estômago cria um fluxo de íons, em que prótons são bombeados de fluidos intracelulares para o lúmen gástrico contra um gradiente. A engenharia enzimática responsável por este transporte ativo é a bomba H+,K+ ATPase, a qual é modulada (estimulação e inibição) por sinais moleculares neuronais e endócrinos. Os IBPs, após a ingestão antes da alimentação, ligam-se apenas às bombas ativadas. São metabolizados pelo complexo enzimático do citocromo P450, CYP 2C19 e CYP 3A4, esta característica contribui para interações medicamentosas com outros fármacos que também possuem o mesmo mecanismo de metabolização. Os IBPs, geralmente, são bem tolerados pelo organismo. Até o momento, estudos descreveram que as reações adversas mais comuns relatadas são dor de cabeça, diarreia e náusea, com incidência de < 10%, valores semelhantes quando comparados com placebo e antagonistas dos receptores H2. A terapia de supressão ácida com IBP está associada a benefícios no manejo de doenças ácido-pépticas. O sucesso desta supressão farmacológica para o processo de cicatrização de úlcera e DRGE está refletindo-se na redução de cirurgias eletivas como tratamento destas enfermidades, além da redução da gastropatia associada a utilização de AINEs...

Evaluation of Cassia singueana extract on stomach HCL production and gastric emptying in rats.

Investigation of the effects of the extract from C. singueana leaves on stomach hydrochloric acid (Hcl) production following histamine administration and on gastric emptying was carried out in rats. Cassia singueana extract (CSE) at 250 and 750 mg/kg significantly (p<0.050) decreased both gastric free-Hcl and total acids as well as the quantity of meal emptied from the stomach when compared with solvent control. The extract at 250 mg/kg exerted a significant decrease in gastric emptying more than cimetidine (100 mg/kg). CSE contains alkaloids, tannins, sterols and terpenes but no flavonoids, saponins, carbohydrates, reducing sugars, starch nor polyuronides.

Anti-ulcer & antioxidant activities of Hedranthera barteri {(Hook F.) Pichon} with possible involvement of H+, K+ ATPase inhibitory activity.

Background & objective: Hedranthera barteri (HB) is used in folk medicine as a vermifuge, laxative and an anti-inflammatory agent. The aim of this study was to evaluate the anti-ulcer and antioxidant properties of the dichloromethane fraction of HB root (DMHBR). Methods: Anti-ulcerogenic activity was assessed in cold-restraint (CRU), aspirin (ASP), alcohol (AL), pyloric ligation (PL) induced gastric ulcer models in rats and histamine-induced duodenal ulcer (HST) in guinea pigs. The effect of DMHBR (100 mg/kg) on gastric juice for free and total acidity, peptic activity and mucin secretion, using the pylorus ligated model, were evaluated. The H+, K+-ATPase activity was assayed in gastric microsomes, spectrophotometrically. The in vitro anti-oxidant assays were explored through DPPH, nitric oxide, hydroxyl radical, superoxide anion scavenging assays. Results: DMHBR reduced the incidence of ulcers in CRU (63.3%), PL (58.5%), ASP (52.7%), HST (75.0%) and AL (53.87%). Also, reductions were observed in the free acidity (49.4%), total acidity (45.8%) and peptic activity (32.9%) with increase in the mucin secretion by 81.6 per cent. DMHBR (60-100 μg/ml) inhibited the H+,K+-ATPase activity with IC50 of 89.64 μg/ml compared with omeprazole (10-50 μg/ml ) with IC50 of 32.26 μg/ml. DMHBR showed antioxidant activity with IC50 values of DPPH (397.69 μg/ml), nitric oxide (475.88 μg/ml), hydroxyl radical (244.22 μg/ml) and superoxide anion radical (285.20 μg/ml). Interpretation & conclusion: DMHBR showed anti-ulcer activity against experimentally-induced peptic ulcer models and exhibited both cytoprotective and anti-secretory property. It exhibited a proton pump inhibition activity and its anti-ulcer properties may be partly ascribed to its antioxidant activities.

Inibidores da bomba protônica / Proton pump inhibitors

Os estudos sobre o efeito do controle do ácido gástrico iniciaram-se há mais de 30 anos. Desde então, inúmeros ensaios clínicos bem conduzidos e metanálises mostraram que os inibidores da bomba protônica (IBP) são significativamente mais efetivos que antagonistas dos receptores H2 da histamina para a realização da supressão ácida gástrica. A secreção ácida nas células parietais do estômago cria um fluxo de íons, em que prótons são bombeados de fluidos intracelulares para o lúmen gástrico contra um gradiente. A engenharia enzimática responsável por esse transporte ativo é a bomba H+,K+ ATPase, a qual é modulada (estimulação e inibição) por sinais moleculares neuronais e endócrinos. Os IBP, após a ingestão antes da alimentação, ligam-se apenas às bombas ativadas. São metabolizados pelo complexo enzimático do citocromo P450, CYP 2C19 e CYP 3A4, esta característica contribui para interações medicamentosas com outros fármacos que também possuem o mesmo mecanismo de metabolização. Os IBP, geralmente, são bem tolerados pelo organismo. Até o momento, estudos descreveram que as reações adversas mais comuns relatadas são: dor de cabeça, diarréia e náusea, com incidência de < 10%, valores semelhantes quando comparados com placebo e antagonistas dos receptores H2. A terapia de supressão ácida com IBP está associada a benefícios no manejo de doenças ácido-pépticas. O sucesso desta supressão farmacológica para o processo de cicatrização de úlcera e DRGE está refletindo-se na redução de cirurgias eletivas como tratamento destas enfermidades, além da redução da gastropatia associada à utilização de AINEs.

The effects of H.pylori and its crude extracted proteins on isolated rabbit parietal cells acid secretion / 中华内科杂志

Objective To explore the effects of H.pylori and crude extracted proteins secreted by H.pylori(broth culture filtrate protein,BCF-P)on acid secretion from isolated rabbit parietal cells.Methods Parietal cells from rabbit gastric mucosa were isolated and enriched with digestion and elutriation.H.pylori(NCTC 11637,CagA+ VacA+)were grown in liquid broth culture and BCF-P was precipitated with ammonium sulfate.The vacuolation activity of BCF-P was evaluated with neutral red dye uptake test in HeLa cell.Isolated parietal cells were incubated with H.pylori(bacteria/cell=100∶1)for 2 h and 16 h,or BCF-P(100μg/ml)for 1 h and 12 h.Acid secretion from parietal cells was studied using 14C-aminopyrine(14C-AP)accumulation indirectly and H+-K+ ATPase α subunit mRNA expression was assessed using RT-PCR.Results (1)BCF-P containing vacuolating cytotoxin(VacA)with vacuolation activity on HeLa cells had positive result on neutral red uptake test.(2)The basal expression of H+-K+ ATPase α subunit mRNA could be detected in isolated parietal cells and 14C-AP accumulation was significantly increased in response to the stimulation of histamine with different concentrations for 30 min(P＜0.05).These results indicated that the isolated parietal cells retain relative intact acid secretion function.(3)The histamine(1.0×104 mol/L)stimulated acid secretion was inhibited sustainedly in response to H.pylori by 81% at 2 h and by 94% at 16 h(P＜0.05).However,H+-K+ ATPase α subunit mRNA expression was up-regulated in tlle acute period(2 h)and was down-regulated in the chronic period (16 h)by H.pylori(P＜0.05).(4)BCF-P significantly inhibited the histamine-stimulated acid secretion by 24% at 1 h and by 58% at 12 h(P＜0.05),and this inhibition was accompanied by the down-regulated expression of H+-K+ATPase α subunit mRNA.Conclusions Intact H.pylori and VacA secreted by H.pylori could directly inhibit histamine-stimulated acid secretion from parietal cells and this inhibition may be mediated by the down-regulated H+-K+ ATPase expression.

Study the inhibitory action of gastric H~+/K~+-ATPase by scopaparia dulcis,extractive from ethanol / 中国实用内科杂志

Objective Study the inhibitory action of gastric H~+/K~+-ATPase by scopaparia dulcis,extractive from ethanol.Methods measure the gastric H~+/K~+-ATPase activity by animal test and inorganic phosphorus measurement method.Results chemical estimation shows the H~+/K~+-ATPase activity of experiment group is lower than that of control group,there is remarkable difference in statistics.Conclusion the scopaparia dulcis'extractive from ethanol can inhibit the rats' gastric H~+/K~+-ATPase activity.

Regulation of Potassium Excretion in the Kidney

The maintenance of potassium balance depends primarily on excretion by the kidney. The regulated secretion of potassium normally accounts for most of urinary potassium excretion. Potassium transport along the nephron has two main features:the ubiquitous Na,K-ATPase defines basolateral membranes, whereas site-specific potassium transporters are responsible for the apical transport. Two different cell types mediate secretion and reabsorption of potassium. Principal cells secrete potassium, whereas intercalated cells, especially those belonging to the subfamily of beta-intercalated cells, reabsorb potassium. The factors that stimulate potassium secretion by the principal cells include (1) increased extracellular fluid potassium concentration (2) increased aldosterone and (3) increased tubular flow rate. One factor that decreases potassium secretion is increased hydrogen concentration (acidosis). In situations associated with severe potassium depletion, there is a cessation of potassium secretion and net reabsorption of potassium. It is believed that H,K-ATPase transport mechanism located in the luminal membrane of the cortical and outer medullary collecting duct cells reabsorb potassium in exchange for hydrogen secreted into the tubular lumen.

Expression of HDC and H~+,K~+-ATPase in gastric mucosa during healing of experimental gastric ulcer in rats / 第三军医大学学报

Objective To investigate the expression changes of histidine decarboxylase(HDC)and H+,K+-ATPase in gastric mucosa during the healing of experimental gastric ulcer in rats.Methods The ulcers were caused by applying acetic acid to the serosal surface of the anterior face of the rat gastric body.At different time points during ulcer healing,HDC and H+,K+-ATPase mRNA and protein expressions were studied by using reverse transcription-polymerase chain reaction and Western blot respectively.Results An ulcer crater developed on the anterior face of the gastric body on day 1 after the induction of ulcers,and the ulcer area was biggest on day 3.On day 12,most of the gastric ulcers had healed.Compared with the control group,the HDC and H+,K+-ATPase mRNA expression in the gastric mucosa of ulcer rats showed a decrease on day 1,and increased back to initial level on day 9.The protein expression of HDC and H+,K+-ATPase in gastric mucosa of ulcer rats decreased immediately on day 1,more on day 6,and returned to the initial levels on day 12.Conclusion The mRNA and protein expressions of HDC and H+,K+-ATPase decrease in the healing process of gastric ulcers,resulting in accelerated ulcer healing through inhibiting gastric acid secretion.

Gastric Adaptive Responses to Chronic Hypokalemia / 대한해부학회지

To date, most of data regarding H/K-ATPase have been derived from alterations of gene expression or enzymatic activity in kidney. But potassium balance is achieved by the control of urinary K+ excretion and by the control of K+ absorption from the digestive tract. The digestive system is also expected to participate substantively in the regulation of systemic K+ homeostasis during chronic hypokalemia. This study was performed to analyze the expression and distribution of the gastric H/K-ATPase alpha subunit mRNA and protein in rats of chronic changes of potassium diet using Northern blot analysis and immunohistochemistry. Northern blot analysis demonstrate that gastric H/K- ATPase alpha subunit mRNA was abundantly expressed in normal rat stomach not in distal colon. In experimental groups, gastric H/K-ATPase alpha subunit mRNA was also abundantly expressed, but there was no significant differences among all groups. By immunohistochemistry, immunoreactivity of gastric H/K-ATPase alpha subunit was detected in the parietal cells. Reaction products were diffusely localized throughout the cytoplasm. Most of these immunoreactive cells were located in the gastric gland between the neck and base portion of the body, but a few cells in the base or gastric pits. All groups exhibited comparable cellular patterns of labeling and signal intensity. These results suggest that gastric H/K-ATPase alpha subunit does not significantly contribute to potassium conservation during chronic changes of potassium diet in spite of abundant expression.

Effect of Chronic Hypokalemia on Expression of Colonic H/K-ATPase a Subunit mRNA in Rat Uterus / 대한해부학회지

Potassium (K+) balance is achieved by the control of urinary K+ excretion and by the control of K+ absorption from the digestive tract. While it is well established that colonic H/K-ATPase a subunit mRNA is expressed in the kidney, distal colon, and uterus, little is known about the cellular localization and expression levels of this gene in chronic hypokalemia. Accordingly, Northern analysis and in situ hybridization (ISH) were carried out to analyze the expression of mRNA encoding the colonic H/K-ATPase a subunit in normal and potassium-restricted (2 weeks) rats. Northern analysis demonstrated that colonic H/K-ATPase a subunit mRNA was abundantly expressed in normal and potassium-restricted rat uterus. Abundance of colonic H/K-ATPase a subunit mRNA in potassium-restricted rat uterus was increased but, not statistically significant compared to that of controls. By ISH, mRNA for colonic H/K-ATPase a subunit was detected in the endometrial epithelial cells and the uterine glands. Both groups exhibited comparable cellular patterns of labeling, but signal intensity of potassium- restricted rats was higher than normal rats. The endometrial epithelial cells exhibited a mixture of hybridization signal intensity. Most cells had intense hybridization signal for colonic H/K-ATPase a subunit mRNA, some cells had moderate, and a few cells had weak. In summary, colonic H/K-ATPase a subunit mRNA is expressed in the endometrial epithelial cells and the uterine glands. These results suggest that two (or more) H/K-ATPase a subunit isoforms are present in rat uterus and this gene contributes to potassium reclamation during chronic hypokalemia to regulate the pH and/or electrolyte concentration of uterine fluid.

Effects of Chronic Hypokalemia on Rat Distal Colon / 대한해부학회지

Recent molecular and physiological studies suggested that at least two distinct H/K-ATPase activities are present in the mammalian colon. Potassium (K+) balance is achieved by the control of urinary K+ excretion and by the control of K+ absorption from the digestive tract. The colon also participates substantively in the regulation of systemic K+ homeostasis. Northern analysis and in situ hybridization (ISH) for analyzing the expression of mRNA encoding the colonic H/K-ATPase a subunit and EM study for morphologic adaptations were carried out in normal and potassium-deprived (2 weeks) rats. Northern analysis demonstrated that colonic H/K-ATPase a subunit mRNA is abundantly expressed in normal rat distal colon. Abundance of colonic H/K-ATPase a subunit mRNA in potassium-deprived rat distal colon was not significantly increased compared to controls. By ISH, mRNA for colonic H/K-ATPase a subunit was detected in the surface epithelial cells, Goblet cells, and upper third of the intestinal gland. Both groups exhibited comparable cellular patterns of labeling and signal intensity. The surface epithelial cells exhibited a mixture of hybridization signal intensity. Most cells had intense hybridization signal for colonic H/K-ATPase a subunit mRNA and some cells had moderate, and a few cells had weak. Occasionally, strong hybridization signal was detected in the lower portion of the intestinal gland. EM study demonstrated that two types of surface columnar epithelial cells were present in normal distal colon and included type 1 cells with more abundant vesicles in supranuclear cytoplasm and type 2 cells with moderate amount of vesicles. In potassium-deprived distal colon, type 2 cells were only present in surface columnar epithelial cells. Others were not significant differences between two groups. These results suggest that two (or more) H/K-ATPase a subunit isoforms are present in rat distal colon, and colonic H/K-ATPase asubunit gene does not significantly contribute to potassium conservation during chronic hypokalemia in spite of abundant expression of this gene.

Renal Adaptive Responses of HK alpha2 Gene(HK alpha 2a, HK alpha 2b) to the Changes of Potassium(K) Diet / 대한신장학회잡지

Recent molecular and physiological studies suggested that at least two H/K-ATPase isozymes are expressed in the rat kidney, and two distinct isoforms(HK alpha 2a, 2b) are resulted from alternative splicing of the 5-end of HK alpha 2 in distal colon by sequence analysis. Northern analysis and in situ hybridization(ISH) were carried out to analyze the expression of HK alpha 2a. and HK alpha 2b, mRNAs in rat kidney according to the changes of K-diet. Isoform specific 32P-labeled cDNA(for Northern) or digoxigenin labeled cRNA(for ISH) probes were used. Northern analysis demonstrated that HK a z. mRNA is abundantly expressed in normal(group 1: normal diet 2W) renal cortex, modestly in normal outer medulla, and weakly in normal inner medulla. The potassium-deprived rats(group 2: K-free diet 1W, and group 4: K-free diet 2W) expressed 40N lower levels in cortex and 2-4 fold higher levels of HKalpha 2a. mRNA in outer and inner medulla compared to normal rat. The potassium loading rats after potassium-deprivation(group 3: normal diet 1W after K-free diet 1W, and group 5: normal diet 1W after K-free diet 2W showed almost normal levels of HK alpha 2a. mRNA. HK alpha 2b, mRNA was not detected in any tissues of groups. By ISH, mRNA for HK alpha 2, was detected in the thick ascending limb, distal convoluted tubule, and the entire collecting duct. All groups exhibited comparable cellular patterns of labeling. Signal intensity of group 2 and 4 was less in cortical collecting duct(CCD), especially principal cells and much higher in the inner stripe of the outer medullary collecting duct(OMCDi) and the proximal inner medullary collecting duct(IMCD) compared to group 1. Group 3 and 5 exhibited signal intensity of group l. These results indicate that chronic hypokalemia enhances expression of HK alpha 2a, gene in OMCDi and proximal IMCD, decreases in CCD, and restores at normal levels in potassium-loading after potassium-deprivation and suggest that this isoform plays an important role in potassium balance by these segments accordiog to the changes of K-diet.

Activity of H~+-K~+-ATPase in gastric parietal cells under stress in rats and analysis of electron microscopic enzyme cytochemistry / 中国病理生理杂志

AIM: To demonstrate the changes of activity and electron microscopic enzyme cytochemistry staining of H+-K+-ATPase of gastric parietal cells under stress in rats.METHODS: Twenty-four male SD rats were randomly divided into normal group,stress group and stress+omeprazole(OM) group.Water immersion-restraint stress(WRS) model in SD rats was performed.The ulcer index(UI) of gastric mucosa and H+-K+-ATPase activity of gastric parietal cells were measured.The changes of ultrastructure and electron microscopic enzyme cytochemistry staining of parietal cells were observed under transmission electron microscope(TEM).RESULTS: Compared with control group,the UI of gastric mucosa and H+-K+-ATPase activity of gastric parietal cells increased(P