茴香提取液对地塞米松诱导大鼠胰岛素抵抗的影响

目的:观察茴香对大鼠胰岛素抵抗(insulin resistance,IR)的影响.方法:取50只大鼠,随机分为5组.正常对照组给予生理盐水,其余各组给予地塞米松(1mg/kg),隔日肌肉注射;正常对照组和模型对照组给予生理盐水,二甲双胍组给予二甲双胍(40g/L),茴香低、高剂量组给予茴香提取液(300、600g/L)每天灌胃;给药15d后,分别检测空腹血糖(FBG)、血清胰岛素(FINS)和糖耐量试验(OGTT),并计算OGTT120’恢复率、胰岛素敏感指数(ISI)和胰岛素抵抗指数(HOMA-IR).结果:二甲双胍组和茴香低、高剂量组的FBG、OGTT120’恢复率与正常对照组无显著性差异,FBG低于模型对照组(P<0.05),而OGTT120’恢复率明显高于模型对照组(P<0.05,0.01),FINS明显高于正常对照组而明显低于模型对照组(P<0.05,0.01),ISI明显低于正常对照组而明显高于模型对照组(P<0.01),HOMA-IR明显低于模型对照组(P<0.01);茴香低剂量组的ISI明显低于茴香高剂量组(P<0.05).随着茴香用量的增大,FBG、OGTT120’、FINS、ISI和HOMA-IR更接近正常对照组.结论:茴香能提高组织细胞对胰岛素的敏感性,改善高胰岛素血症,并有降血糖的作用.     

胃舒散对乙醇诱导大鼠急性胃损伤的保护作用

目的研究胃舒散对乙醇所致急性胃黏膜损伤（AGML）的保护作用。方法采用乙醇灌胃诱导大鼠AGML模型。采用光镜、扫描电镜和透射观察不同剂量胃舒散（3．0、1．5、0．75g／kg）对黏膜组织形态学的保护作用，并同时检测胃黏膜局部血流量（GMBF）、跨膜电位（PD）、胃组织超氧化物歧化酶（SOD）活性、丙二醛（MDA）含量和血浆NO水平，等容积的生理盐水和丽珠得乐（1．0g／kg）分别作为正常对照和治疗对照组。结果胃舒散组胃黏膜损伤指数及组织学评分均较模型对照组显著降低（P〈0．05，P〈0．01）；GMBF及PD较模型对照组显著增高（P〈0．0l，P〈0．05）；胃舒散可明显提高胃组织SOD活性（P〈0．05）及血浆NO水平（P〈0．叭）。结论胃舒散对乙醇所致AGML有明显的保护作用，其作用机制可能与增加胃黏膜血流及抗氧化作用有关。     

复方尿囊素片对乙醇所致大鼠胃黏膜损伤保护作用的实验研究

目的研究复方尿囊素片对乙醇所致大鼠急性胃黏膜损伤的预防保护作用及其机制。方法 60只健康雄性Wistar大鼠随机分为5组：乙醇损伤组、空白对照组、硫糖铝保护组、氢氧化铝保护组、复方尿囊素保护组。保护组分别用硫糖铝、氢氧化铝及复方尿囊素片提前给大鼠灌胃,其后用乙醇灌胃致急性胃黏膜损伤,然后分别测定各组胃黏膜溃疡指数、黏膜损伤积分、胃黏膜血流、黏膜前列腺素E2（PGE2）及一氧化氮（NO）含量,并在显微镜及电镜下观察胃黏膜组织学改变。结果复方尿囊素保护组的各项检测指标显示：溃疡指数、损伤积分显著低于乙醇损伤组（P=0.000,P=0.000）,明显低于氢氧化铝保护组（P=0.020,P=0.004）,也低于硫糖铝保护组,但差异无统计学意义（P=1.000,P=1.000）;黏膜血流值较乙醇损伤组明显增加（P=0.000）,明显高于氢氧化铝保护组（P=0.019）,与硫糖铝保护组的差异无统计学意义（P=0.266）;黏膜PGE2及NO含量均较乙醇损伤组明显增加（P=0.000,P=0.001）,明显高于氢氧化铝保护组（P=0.002,P=0.001）,也高于硫糖铝保护组,但差异无统计学意义（P=0.451,P=0.199）。结论复方尿囊素片对乙醇所致大鼠急性胃黏膜损伤有明显的预防保护作用,其作用是通过增加胃黏膜血流、增加黏膜PGE2及NO含量等机制实现的。     

Influence of zinc sulfate intake on acute ethanol-induced liver injury in rats

AIM: To investigate the role of metallothionein and proliferating cell nuclear antigen (PCNA) on the morphological and biochemical effects of zinc sulfate in ethanol-induced liver injury. METHODS: Wistar albino rats were divided into four groups. GroupⅠ; intact rats, groupⅡ; control rats given only zinc, groupⅢ; animals given absolute ethanol, group IV; rats given zinc and absolute ethanol. Ethanol-induced injury was produced by the 1 mL of absolute ethanol, administrated by gavage technique to each rat. Animals received 100 mg/kg per day zinc sulfate for 3 d 2 h prior to the administration of absolute ethanol. RESULTS: Increases in metallothionein immunoreactivity in control rats given only zinc and rats given zinc and ethanol were observed. PCNA immunohistochemistry showed that the number of PCNA-positive hepatocytes was increased significantly in the livers of rats administered ethanol + zinc sulfate. Acute ethanol exposure caused degenerative morphological changes in the liver. Blood glutathione levels decreased, serum alkaline phosphatase and aspartate transaminase activities increased in the ethanol group when compared to the control group. Liver glutathione levels were reduced, but lipid peroxidation increased in the livers of the group administered ethanol as compared to the other groups. Administration of zinc sulfate in the ethanol group caused a significant decrease in degenerative changes, lipid peroxidation, and alkaline phosphatase and aspartate transaminase activities, but an increase in liver glutathione. CONCLUSION: Zinc sulfate has a protective effect on ethanol-induced liver injury. In addition, cell proliferation may be related to the increase in metallothionein immunoreactivity in the livers of rats administered ethanol + zinc sulfate.     

Gastroprotective activity of Nigella sativa L oil and its constituent, thymoquinone against acute alcohol-induced gastric mucosal injury in rats

AIM: To evaluate the role of reactive oxygen species in the pathogenesis of acute ethanol-induced gastric mucosal lesions and the effect of Nigella sativa L oil (NS) and its constituent thymoquinone (TQ) in an experimental model. METHODS: Male Wistar albino rats were assigned into 4 groups. Control group was given physiologic saline orally (10 mL/kg body weight) as the vehicle (gavage); ethanol group was administrated 1 mL (per rat) absolute alcohol by gavage; the third and fourth groups were given NS (10 ml/kg body weight) and TQ (10 mg/kg body weight p.o) respectively 1 h prior to alcohol intake. One hour after ethanol administration, stomach tissues were excised for macroscopic examination and biochemical analysis. RESULTS: NS and TQ could protect gastric mucosa against the injurious effect of absolute alcohol and promote ulcer healing as evidenced from the ulcer index (UI) values. NS prevented alcohol-induced increase in thiobarbituric acid-reactive substances (TBARS), an index of lipid peroxidation. NS also increased gastric glutathione content (GSH), enzymatic activities of gastric superoxide dismutase (SOD) and glutathione-S-transferase (GST). Likewise, TQ protected against the ulcerating effect of alcohol and mitigated most of the biochemical adverse effects induced by alcohol in gastric mucosa, but to a lesser extent than NS. Neither NS nor TQ affected catalase activity in gastric tissue. CONCLUSION: Both NS and TQ, particularly NS can partly protect gastric mucosa from acute alcohol-induced mucosal injury, and these gastroprotective effects might be induced, at least partly by their radical scavenging activity.     

Nitric oxide-mediated gastric hyperemia decreases ethanol-induced gastric mucosal injury in uremic rats

We investigated whether the recently described endothelium-derived nitric oxide-mediated gastric hyperemia in the uremic rat protects the gastric mucosa against ethanol injury. Uremia was induced by subtotal nephrectomy. Basal gastric mucosal blood flow, measured by a hydrogen gas clearance technique, was significantly higher in uremic than control rats. Continuous intragastric perfusion with 40% ethanol produced significantly less gross and histological lesions in uremic than in control rats. The administration of 3 mg/kg ofN ^W-nitro-l-arginine methyl ester, a specific inhibitor of nitric oxide biosynthesis, decreased resting gastric mucosal blood flow to control levels in uremic rats, but had no effect on basal gastric blood flow in control rats. This pretreatment with the inhibitor of nitric oxide biosynthesis increased 40% ethanol-induced gastric mucosal lesions in uremic rats to the same level as that observed in control rats, but had no effect on lesions in control rats. In conclusion, this study suggests that in the uremic rat, gastric hyperemia, mediated by increased endothelium-derived nitric oxide, attenuates ethanol-induced gastric mucosal injury.Dr. Enrique Quintero is the recipient of a Fogarty International Fellowship Award (N.I.H.) (1 FO5 TW04443-01) and a Grant from Consejería de Educación, Cultura y Deportes of the Canary Islands Autonomous Government. This work was also supported by Veterans Administration Research Funds.     

Ontogeny of acute tolerance to ethanol-induced social inhibition in Sprague-Dawley rats

BACKGROUND: Adolescent rats are less sensitive than adults to a number of acute effects of ethanol, including ethanol-induced social inhibition. Adolescent insensitivity to the suppressing effects of ethanol on social interactions could be related in part to age differences in compensatory responses, including acute tolerance, that serve to counteract these inhibitory effects of ethanol. The present study explored ontogenetic development of acute tolerance within 30 minutes after administration of a relatively low ethanol dose, using ethanol-induced social impairment as the target response measure. METHODS: Overall social activity was examined following challenge with 1 g/kg ethanol (intraperitoneally) at 2 postinjection intervals (5 or 30 minutes) in early [postnatal day (P) 28], mid (P35), or late (P42) adolescent or adult (P70) group-housed male and female Sprague-Dawley rats (Experiment 1). Blood and brain ethanol concentrations (BECs and BrECs) were assessed in separate groups of animals 5 or 30 minutes after ethanol administration (Experiment 2). Expression of acute tolerance was examined by assessing the relationship between BrECs and the degree of social impairment in individual animals at P28, P35, P42, and P70 during early recovery period (up to 30 minutes) following acute ethanol challenge (Experiment 3). RESULTS: Effects of ethanol on overall social activity were age-dependent and time-dependent. Whereas all age groups showed equivalent ethanol-induced social inhibition 5 minutes after injection, testing at 30 minutes revealed marked age differences. Social inhibition was still pronounced at this time in adults, but was diminished in an age-related manner at younger ages (Experiment 1). In contrast to the ontogenetic differences in rates of decline in social impairment across time, decreases in brain and blood ethanol levels over time were similar across age (Experiment 2). Only P28 and P35 adolescents showed acute tolerance to ethanol-induced social inhibition, as indexed by an increasing time-dependent dissociation between BrECs and ethanol-induced social impairment, with social impairment declining faster than BrECs (Experiment 3). CONCLUSIONS: This is the first study to document enhanced acute tolerance in adolescent rats relative to adult animals at nonhypnotic doses of ethanol. The greater expression of acute tolerance in young animals may reflect an enhanced predisposition of their nervous systems to respond rapidly to even modest doses of ethanol with compensatory adaptations. A greater propensity of early adolescents to develop acute tolerance may contribute to their resistance to adverse effects of ethanol, thereby permitting heavy drinking at this age and placing early adolescents at higher risk for extensive alcohol use.     

酒精性胃粘膜损伤的研究进展

酒精性胃粘膜损伤是由于过量饮酒或长期饮酒后造成的胃粘膜的急性或慢性损伤,临床上常引起急性胃炎或慢性胃炎。此文就酒精的代谢过程、酒精性胃粘膜损伤的发病机制及其干预研究进行综述。     

Protective effects of Ginkgo biloba extract on the ethanol-induced gastric ulcer in rats

AIM: To evaluate the preventive effect of Ginkgo biloba extract (GbE) on ethanol-induced gastric mucosal injuries in rats. METHODS: Female Wistar albino rats were used for the studies. We randomly divided the rats for each study into five subgroups: normal control, experimental control, and three experimental groups. The gastric ulcers were induced by instilling 1 mL 50% ethanol into the stomach. We gave GbE 8.75,17.5,26.25 mg/kg intravenously to the experimental groups respectively 30 min prior to the ulcerative challenge. We removed the stomachs 45 min later. The gastric ulcers, gastric mucus and the content of non-protein sulfhydryl groups (NP-SH), malondialdehyde (MDA), c-Jun kinase (JNK) activity in gastric mucosa were evaluated. The amount of gastric juice and its acidity were also measured. RESULTS: The findings of our study are as follows: (1) GbE pretreatment was found to provide a dose-dependent protection against the ethanol-induced gastric ulcers in rats; (2) the GbE pretreatment afforded a dose-dependent inhibition of ethanol-induced depletion of stomach wall mucus, NP-SH contents and increase in the lipid peroxidation (increase MDA) in gastric tissue; (3) gastric ulcer induced by ethanol produced an increase in JNK activity in gastric mucosa which also significantly inhibited by pretreatment with GbE; and (4) GbE alone had no inhibitory effect on gastric secretion in pylorus-ligated rats. CONCLUSION: The finding of this study showed that GbE significantly inhibited the ethanol-induced gastric lesions in rats. We suggest that the preventive effect of GbE may be mediated through: (1) inhibition of lipid peroxidation; (2) preservation of gastric mucus and NP-SH; and (3) blockade of cell apoptosis.     

Reversing gastric mucosal alterations during ethanol-induced chronic gastritis in rats by oral administration of Opuntia ficus-indica mucilage

AIM: To study the effect of mucilage obtained from cladodes of Opuntia ficus-indica (Cactaceae) on the healing of ethanol-induced gastritis in rats. METHODS: Chronic gastric mucosa injury was treated with mucilage (5 mg/kg per day) after it was induced by ethanol. Lipid composition, activity of 5'-nucleotidase (a membrane-associated ectoenzyme) and cytosolic activities of lactate and alcohol dehydrogenases in the plasma membrane of gastric mucosa were determined. Histological studies of gastric samples from the experimental groups were included. RESULTS: Ethanol elicited the histological profile of gastritis characterized by loss of the surface epithelium and infiltration of polymorphonuclear leukocytes. Phosphatidylcholine (PC) decreased and cholesterol content increased in plasma membranes of the gastric mucosa. In addition, cytosolic activity increased while the activity of alcohol dehydrogenases decreased. The administration of mucilage promptly corrected these enzymatic changes. In fact, mucilage readily accelerated restoration of the ethanol-induced histological alterations and the disturbances in plasma membranes of gastric mucosa, showing a univocal anti-inflammatory effect. The activity of 5'-nucleotidase correlated with the changes in lipid composition and the fluidity of gastric mucosal plasma membranes. CONCLUSION: The beneficial action of mucilage seems correlated with stabilization of plasma membranes of damaged gastric mucosa. Molecular interactions between mucilage monosaccharides and membrane phospholipids, mainly PC and phosphatidylethanolamine (PE), may be the relevant features responsible for changing activities of membrane-attached proteins during the healing process after chronic gastric mucosal damage.     

The influence of acute or chronic nicotine treatment on ethanol-induced gastric mucosal damage in rats

The influences of acute or chronic nicotine pretreatment on ethanol-induced changes on gastric secretion, mucosal blood flow (GMBF), and glandular mucosal damage were studied in anesthetized rats. Ethanol administration decreased gastric acid secretion and GMBF, which were accompanied by a marked increase in gastric mucosal damage. Acute nicotine incubation 2 or 4 mg dose-dependently elevated both the titratable acid in the luminal solution and the gastric secretory volume; it also prevented the depressive action on GMBF and gastric mucosal damage in ethanol-treated animals. Chronic nicotine treatment for 10 days reduced the inhibitory action of ethanol on gastric acid secretion; the higher dose (25 micrograms/ml drinking water) potentiated the decrease of GMBF and the ulcerogenic property of ethanol. However, chronic treatment with the lower dose (5 micrograms/ml drinking water) had the opposite effects; it also markedly increased the gastric secretory volume. It is concluded that acute nicotine pretreatment elevates, whereas chronic nicotine pretreatment differentially affects GMBF. These effects could account for their protective or preventive actions on ethanol ulceration. The increase in nonacid gastric secretory volume by nicotine could partially explain its antiulcer effect. Furthermore, the acid secretory state of the stomach appears unrelated to the ulcerogenic property of ethanol.     

丹参对实验性急性乙醇胃粘膜损伤的保护作用及其机理的研究

采用无水乙醇制备急性胃粘膜损伤模型，观察丹参水溶液对急性胃粘膜损伤的影响。大鼠分为对照组、乙醇损伤组及丹参水溶液保护组。乙醇灌胃给人，保护组给予丹参水溶液后再给乙醇。结果表明：保护组与损伤组比较，胃壁结合粘液量、胃粘膜血流量增多，ＳＯＤ、ＧＳＨ－Ｐｘ活性增高，ＬＰＯ含量降低，胃粘膜损伤指数明显减低。认为丹参水溶液对乙醇急性胃粘膜损伤有保护作用，此与其增强胃粘膜防御功能、清除氧自由基及抑制脂质过氧化反应有关。     

Effects of benzodiazepines on acute and chronic ethanol-induced nociception in rats

BACKGROUND: Acute and chronic ethanol produces antinociception, and ethanol withdrawal induces hyperalgesia. METHODS: A radiant heat tail-flick assay was used to assess the effects of benzodiazepine ligands on ethanol-induced changes in nociception in rats. Acute activity of cumulative doses of ethanol (0.5-2.0 g/kg) and diazepam (0.1-10 mg/kg), a benzodiazepine agonist, was tested alone and after pretreatment with flumazenil (1.0-10 mg/kg), a benzodiazepine antagonist. Chronic effects of ethanol were tested in three groups of rats that received a liquid diet for 10 days. One group received ethanol alone; one group received ethanol and twice-daily injections of flumazenil (10 mg/kg); and one received a dextrin control diet. Acute withdrawal was tested at 12 hr after removal of the liquid diet. Effects of cumulative doses of diazepam (1.0-10 mg/kg) were tested during withdrawal (12 hr) in the ethanol-alone group. RESULTS: Acute doses of ethanol produced a small but significant degree of antinociception, which was fully suppressed by flumazenil. Acute doses of diazepam did not produce antinociception. Chronic exposure to ethanol produced antinociception on days 2 through 8. Tolerance developed by day 10, and hyperalgesia was seen 12 hr after removal of ethanol. Administration of diazepam or ethanol during withdrawal reversed the hyperalgesia induced by ethanol withdrawal. However, flumazenil (10-50 mg/kg) failed to reverse the antihyperalgesic effect of either diazepam or ethanol. No antinociception was seen in either the ethanol/flumazenil or dextrin control groups. CONCLUSIONS: These results suggest that the antinociceptive effects of both acute and chronic ethanol are at least partially mediated by GABA receptors, and that diazepam's antihyperalgesic effects may not be mediated by the GABA acid receptor.     

Protective effects of the whisky congeners on ethanol-induced gastric mucosal damage

BACKGROUND: The ingestion of both ethanol and whisky can induce acute gastrointestinal bleeding. The effects of the congeners, substances other than ethanol in whisky, on the ethanol-induced gastric mucosal damage were examined in the rat model. METHODS: After the whisky congeners were intragastrically administered previous to or simultaneous with ethanol ingestion, the gastric damage was macroscopically and microscopically measured. RESULTS: The simultaneous administration of the whisky congeners at a dose of 5 mg/kg body weight, which corresponds to the concentration of congeners contained in whisky, with 50% ethanol did not inhibit the hemorrhagic lesions, but inhibited them at a dose of 150 mg/kg. The treatment with the whisky congeners 30 minutes before the ethanol ingestion prevented the ethanol-induced gastric damage in a dose-dependent manner at 0.5 to 150 mg/kg. The butanol extract of the congeners revealed the strongest prevention compared with the ethyl acetate extract or the water fraction. The administration of indomethacin 60 minutes before the congener treatment partly inhibited the protective effects of the congeners, indicating the partial contribution of prostaglandins in this mechanism. The congeners did not prevent the mucosa by action as a "mild irritant" because the immunohistochemical studies using the antimucin monoclonal antibodies showed that no damage was induced by the administration of the congeners. CONCLUSION: The present results showed that the whisky congeners have a protective activity against ethanol-induced gastric mucosal injury.     

Dual effects ofN-ethylmaleimide on ethanol-induced gastric lesions in rats

The effects ofN-ethylmaleimide (NEM), a sulfhydryl (SH) blocker, on ethanol-induced gastric lesions were investigated in rats by varying the route of administration. Oral administration of acidified ethanol (60% ethanol in 150 mM HCl, 1 ml) produced hemorrhagic bandlike lesions in the gastric mucosa. Pretreatment of the animals with orally administered NEM (0.1–10 mg/kg) dose-dependently inhibited these lesions (the inhibition was over 80% at 1mg/kg or greater) and the effects were partially reversed by indomethacin (5 mg/kg, subcutaneous). However, when NEM (10 mg/kg) was given subcutaneously, this agent significantly worsened the lesions. Intragastrically applied NEM produced a dose-dependent reduction of the transmucosal potential difference (PD) and the mucosal nonprotein SH levels, an, increase of the volume of gastric contents, and an inhibition of gastric motility, while these parameters remained unaltered after subcutaneous administration of the agent. The microvascular permeability in the mucosa was significantly increased by both oral and subcutaneous administration of NEM (10 mg/kg) but remained unchanged in response to lower doses of orally administered (<3 mg/kg). These results suggest that NEM given orally is cytoprotective, to the stomach against ethanol, probably by acting as a mild irritant and due to dilution of an irritant and inhibition of gastric motility (muscle relaxation), but when given subcutaneously it aggravates the lesions by unknown mechanisms.This material was presented at the 2nd International Symposium on Cell Injury and Cytoprotection, held in Boston, July 12–14, 1989.     

Intracisternal injection of orexin-A prevents ethanol-induced gastric mucosal damage in rats

Background Accumulating evidence indicates that orexin-A in the brain stimulates vagal flow projecting to the stomach. Since the vagal system plays an important role in gastric mucosal integrity, we hypothesized that orexin-A in the brain might have a gastroprotective action. Methods We examined the effect of centrally administered orexin-A on the development of gastric mucosal damage evoked by ethanol and its possible mechanism of action in rats. Results Intracisternal but not intraperitoneal injection of orexin-A significantly inhibited the severity of gastric mucosal damage by 70% ethanol in a dose-dependent manner, suggesting that orexin-A acts in the brain to prevent ethanol-induced gastric mucosal damage. The antiulcer action was observed in rats administered with orexin-A centrally but not orexin-B, indicating that the action is mediated through orexin 1 receptors. The gastroprotective action of centrally administered orexin-A was blocked by pretreatment with atropine, N ^ω-nitro-l-arginine methylester, or indomethacin. Conclusions These results suggest that orexin-A acts on orexin 1 receptors in the brain to exert a gastroprotective action against ethanol. The vagal muscarinic system, nitric oxide, and prostaglandins may mediate the cytoprotective action of centrally administered orexin-A.     

一氧化氮、内皮素及氧自由基对大鼠酒精性胃损害的作用研究

目的研究大鼠酒精性胃损害中,一氧化氮(NO)、内皮素(ET)和氧自由基的作用,以及NO对ET-1、丙二醛(MDA)水平的影响.方法以酒精给大鼠灌胃制备急性胃粘膜损害模型,实验分为五组,应用L-NAME或/和L-Arg依不同分组行尾静脉注射.取门脉血测定NO、ET-1和MDA水平,并取出胃进行形态学观察.结果酒精灌胃后,大鼠门脉血NO含量降低,ET-1和MDA量升高,粘膜损伤加重.L-NAME组NO进一步减少,ET-1和MDA更加升高,粘膜损伤明显加重.L-Arg与L-NAME合用后NO、ET-1及MDA水平均有不同程度恢复,粘膜损伤亦减轻.NO与ET-1及MDA水平呈负相关.结论在酒精性胃损害中,ET-1与氧自由基生成增加,起损害作用,内源性NO可调节ET-1的生成,清除氧自由基而发挥保护作用.     

Modulatory action of adenosine on gastric function and ethanol-induced mucosal damage in rats

This study examines the gastric effects of adenosine and its antagonist, theophylline, on secretory function, mucosal blood flow, and on ethanol-induced glandular mucosal damage in rats that were fasted for 24 hr before experimentation. The animals were anesthetized with sodium pentobarbitone (50 mg/kg intraperitoneal) and their tracheae cannulated. An ex vivo stomach chamber then was prepared. The luminal bathing solution was collected every 15 min and the concentrations of H⁺ and Na⁺ were determined by a pH autotitrator and an ionmeter, respectively. The glandular mucosal blood flow was measured by a laser Doppler flowmeter and the severity of lesions was determined by measuring the hemorrhagic areas. Adenosine administration (2.5 or 7.5 mg/kg, subcutaneous) markedly lowered the H⁺ and Na⁺ output but increased the secretory volume and mucosal blood flow in a dose-dependent manner. The same doses of the nucleoside also prevented ethanol-induced mucosal damage. These effects were prevented by pretreatment with theophylline (30 or 60 mg/kg, subcutaneous). Ethanol given alone significantly depressed the H⁺ and Na⁺ secretion. Both effects were not modified by adenosine treatment. However, the depressive action of ethanol on mucosal blood flow was prevented by adenosine. These findings indicate that adenosine modulates the physiological function of the stomach. It also directly activates the defensive mechanism of the stomach, which is partially mediated by the improvement of the gastric mucosal blood flow and an increase in the nonacid component of gastric secretion.