Effect of bafilomycin A1, a specific inhibitor of vacuolar (V-type) proton ATPases, on the capacitation of rabbit spermatozoa

Mammalian spermatozoa maintain precisely regulated ionic gradients that must be modified during capacitation and the acrosome reaction. In other cell types, ionic gradients are mainly regulated by the presence in plasma membranes of three metabolically different types of ATPases. The modifications induced during in vitro capacitation of rabbit spermatozoa by the specific inhibition of V-type H+-ATPases with bafilomycin A were studied. We used chlortetracycline binding to rabbit spermatozoa to monitor capacitation, and the coomassie brilliant blue method to identify acrosome-reacted sperm cells. There was a significant difference between the percentage of epididymal (66 +/- 7%) and ejaculated (43 +/- 11%) spermatozoa capacitated in vitro, after a 6-h incubation period in the presence of Ca2+ without ATPase inhibitor. The presence of bafilomycin significantly reduced these numbers (25 +/- 11 and 16+/- 8%, epididymal and ejaculated spermatozoa, respectively) and eliminated the difference. Ejaculated spermatozoa capacitated in the absence of bafilomycin showed a linear increase in the percentage of acrosome reactions induced by the addition of A23187 (12 +/- 5, 23+/- 6 and 31 +/- 5 after 15, 30 and 45 min). The presence of 0.2 micromol l-1 bafilomycin during the capacitation incubation induced a significant decrease in the acrosome reaction percentages (4 +/- 2, 8 +/- 3 and 14 +/- 4 after 15, 30 and 45 min). The addition of bafilomycin after the capacitating period had no effect upon the induction of the acrosome reaction by A23187. These results indicate that vacuolar ATPases play an important role during rabbit sperm capacitation. However, once the spermatozoa have been capacitated, V-type ATPases do not have a significant participation during the acrosome reaction.     

七氟醚麻醉对大鼠脑ATP酶的动态影响

目的 观察七氟醚吸入麻醉不同时期大鼠各脑区Na~ 、K~ -ATP酶和Ca~(2 )-ATP酶活性动态变化规律,以了解脑ATP酶活性变化在七氟醚麻醉效应中的地位。方法 40只SD大鼠随机均分为对照组、诱导期组、麻醉期组、恢复期组和清醒期组。分光光度法测定不同时期大脑皮质、脑干、海马Na~ 、K~ -ATP酶和Ca~(2 )-ATP酶活性变化。结果 与对照组比较,大鼠大脑皮质、脑干、海马Na~ 、K~ -ATP酶活性在诱导期分别降低21.9％、10.5％、19.3％(P<0.05),麻醉期分别降低37.2％、33.5％、38.9％(P均<0.01),恢复期又开始回升,但仍低于对照组水平(P<0.05或P<0.01),而清醒期基本恢复至对照组水平(P>0.05);大脑皮质、脑干、海马Ca~(2 )-ATP酶活性在诱导期分别降低34.3％、44.3％、25.5％(P<0.05 or P<0.01),麻醉期分别降低39.6％、60.4％、57.6％(P均<0.01),恢复期开始回升,清醒期基本恢复至对照组水平(P>0.05)。结论七氟醚对大鼠大脑皮质、脑干、海马Na~ 、K~ -ATP酶和Ca~(2 )-ATP酶活性的抑制程度与麻醉时相相对应,ATP酶活性与麻醉深度具有相同的变化趋势,表明上述脑区ATP酶可能是七氟醚的作用靶点,与七氟醚的麻醉效应有关。     

Blunted renal dopaminergic system activity in puromycin aminonucleoside-induced nephrotic syndrome.

BACKGROUND: A primary tubular sodium handling abnormality has been implicated in the edema formation of nephrotic syndrome. Dopamine synthesized by renal proximal tubules behaves as an endogenous natriuretic hormone by activating D(1)-like receptors as a paracrine/autocrine substance. METHODS: We examined the time courses of the urinary excretion of sodium, protein and dopamine in puromycin aminonucleoside (PAN)-treated and control rats. The rats were sacrificed during greatest sodium retention (day 7) as well as during negative sodium balance (day 14) for the evaluation of renal aromatic l-amino acid decarboxylase (AADC) activity, the enzyme responsible for the synthesis of renal dopamine. Also, the influence of volume expansion (VE) and the effects of the D(1)-like agonist fenoldopam (10 microg/kg bw/min) on natriuresis and on proximal tubular Na(+),K(+)-ATPase activity were examined on day 7. RESULTS: The daily urinary excretion of dopamine was decreased in PAN-treated rats, from day 5 and beyond. This was accompanied by a marked decrease in the renal AADC activity, on days 7 and 14. During VE, the fenoldopam-induced decrease in proximal tubular Na(+),K(+)-ATPase activity was more pronounced in PAN-treated rats than in controls. However, the urinary sodium excretion during fenoldopam infusion was markedly increased in control rats but was not altered in PAN-treated animals. CONCLUSION: PAN nephrosis is associated with a blunted renal dopaminergic system activity which may contribute to enhance the proximal tubular Na(+),K(+)-ATPase activity. However, the lack of renal dopamine appears not to be related with the overall renal sodium retention in a state of proteinuria.     

7-氯苄基四氢巴马汀对大鼠心肌肥厚及左心室肌原纤维Ca~(2 )-Mg~(2 )-ATP酶活力的影响

目的观察 7-氯苄基四氢巴马汀 ( 7-chlor -BTHP)对大鼠心肌肥厚和心室肌原纤维质膜Ca2 -Mg2 -ATP酶活力的影响。方法用L -甲状腺素诱发大鼠心肌肥厚 ,然后观察 7-chlor -BTHP对大鼠心肌肥厚及左心室肌原纤维Ca2 -Mg2 -ATPase的影响 ,以普萘洛尔 (Pro)作为阳性对照。结果经过 7-chlor-BTHP治疗 3天后 ,心肌肥厚明显改善 ,Ca2 -Mg2 -ATPase活力明显降低。结论 7-chlor-BTHP能明显消退L -甲状腺素诱发的大鼠心肌肥厚 ,并能显著降低心室肌原纤维膜Ca2 -Mg2 -ATPase酶活力。     

高碳酸血症对大鼠急性肺损伤Na+-K+-ATP酶活性的影响

目的: 研究高碳酸血症(HPC)对急性肺损伤(ALI)时肺泡Na -K -ATP酶活性的影响.方法: 将24只SD大鼠随机分为3组,每组8只:正常对照组(Ⅰ组);ALI组(Ⅱ组);ALI HPC组(Ⅲ组).用0.2 mol/L盐酸(2 ml/kg)气管内滴入建立大鼠急性肺损伤模型,吸入8% CO2气体建立高碳酸血症模型.以肺组织病理变化、支气管肺泡灌洗液(BALF)细胞计数和蛋白浓度、肺湿干重比(W/D)、血和BALF中TNF-α浓度及IL-8浓度为评估肺损伤的指标;以Na -K -ATP酶活性变化为评估HPC疗效的指标.结果: Ⅲ组BALF细胞计数(1.02±0.48),W/D(7.24±0.58),BALF蛋白浓度(0.25±0.16)和IL-8浓度(29.95±7.11)比Ⅱ组相应指标(1.79±0.73;8.60±1.24;0.53±0.35;59.52±36.00)明显降低(P＜0.01);Ⅲ组血TNF-α浓度(83.86±46.93)、IL-8浓度(80.00±24.72)比Ⅱ组相应指标(161.57±54.12;110.00±15.92) 明显降低(P＜0.01);Ⅲ组Na -K -ATP酶活性(13.23±1.20) 比Ⅱ组(10.77±2.21)明显增高(P＜0.01).结论: HPC对ALI时肺泡Na -K -ATP酶的活性有保护作用, 这可能是HPC对盐酸诱导的大鼠ALI保护作用的重要机制.     

Inverse relationship between colonic (Na+ + K+)-ATPase activity and degree of mucosal inflammation in inflammatory bowel disease

In inflammatory bowel disease (IBD), mucosal damage and loss of colonic function are regarded as major consequences of inflammation. Decreased colonic (Na⁺ + K⁺)-ATPase activities with diminished reabsorption of sodium and water have been found in active stages of ulcerative colitis. In this study, we report an inverse relationship between colonic (Na⁺ + K⁺)-ATPase activity and the degree of mucosal inflammation in 19 patients with IBD of mild to moderate disease activity. Various macroscopic and histologic types of mucosal lesions were differently associated with the (Na⁺ + K⁺)-ATPase activities. 5-nucleotidase activity was not associated with the degree of mucosal inflammation or the kind of macroscopic or histologic lesions. Our findings support the view that, in contrast to 5-nucleotidase, (Na⁺ + K⁺)-ATPase activity may better reflect the severity of mucosal damage and the degree of inflammation in IBD.     

Endoxin Antagonist Lessens Myocardial Ischemia Reperfusion Injury

OBJECTIVE: To elucidate whether endoxin is one of important factors involved in myocardial ischemia reperfusion (MIR) injury, the change of myocardial endoxin level was determined in rats with MIR injury model and the effects of anti-digoxin antiserum (ADA), an endoxin specific antagonist, on MIR injury were studied. METHODS: MIR injury model was obtained by ligating left anterior descending coronary artery 30 min followed by 45 min reperfusion. Sprague-Dawley rats were randomly divided into six groups of 10 rats, each. Sham group, MIR group, normal saline group, ADA 9, 18 and 36 mg.kg(-1). ECG was continuously recorded. After reperfusion left ventricular myocardium samples of ischemic area were processed immediately. Myocardial endoxin level, Na(+)-K(+)-ATPase, Ca(2+)-ATPase, Mg(2+)-ATPase activities, and intramitochondrial Ca(2+) content were measured. RESULTS: Myocardial endoxin level was significantly increased; Na(+)-K(+)-ATPase, Ca(2+)-ATPase, and Mg(2+)-ATPase activities were remarkably decreased; intramitochondrial Ca(2+) content was remarkably raised; ST segments of ECG were significantly elevated and occurrence and scores of ventricular arrhythmias were significantly increased in early stage of reperfusion in rats with MIR. In all groups with ADA, myocardial endoxin level was remarkably decreased; Na(+)-K(+)-ATPase, Ca(2+)-ATPase and Mg(2+)-ATPase activities were drastically increased; intramitochondrial Ca(2+) content was declined; ST segments and ventricular arrhythmias were improved. CONCLUSION: Myocardial endoxin level was increased in MIR, which implies that the elevated endoxin may be one of major factors inducing MIR injury. This postulate is supported by the observation that ADA has protective and therapeutic effects against MIR injury probably by antagonizing the action of endoxin. The underlying mechanism may be ascribed to restoration of energy metabolism, and attenuation of intracellular Ca(2+) overload.     

地方性砷中毒膜毒理学研究

以红细胞膜作为观察标志，从膜毒理学角度探讨地方性砷中毒的发病机理。砷中毒病人血砷０．１１±０．０５５μｇ／ｍｌ，红细胞膜砷０．１０１±０．０５μｇ／ｍｇ膜蛋白，胞浆砷０．００１２±０．０００７μｇ／ｍｇＨｂ；电子显微镜观察到红细胞膜破损，异形红细胞，细胞表面毛刺样改变；胞膜的损伤，引起红细胞免疫功能下降，血液流变学的变化，细胞膜ＡＴＰａｓｅ活性下降，红细胞电泳速度减慢和微循环变化，且甲皱微循环的变     

定心汤对心律失常大鼠模型的影响

目的  研究定心汤对心律失常大鼠模型的作用及各项相关指标的影响。方法  采用乌头碱所致心律失常模型观察药物作用。结果  定心汤对乌头碱致大鼠室性心律失常模型有明显作用,缩短心律失常持续时间,降低血清丙二醛（MDA）含量,增加血清超氧化物歧化酶（SOD）活性,增加心肌组织中Na+-K+-ATP酶、Ca2+-ATP酶活性。结论  定心汤有明显的抗室性心律失常作用,且呈剂量依赖性。

     

Effect of extracellular volume expansion on renal cortical and medullary Na+−K+-ATPase

Summary The role of renal Na⁺–K⁺-ATPase in the acute changes in sodium reabsorption caused by isotonic volume expansion was evaluatedin vivo andin vitro in the rat and the dog. Duringin vivo volume expansion with isotonic saline in the rat, renal medullary Na⁺–K⁺-ATPase specific activity increased, while the simultaneously determined cortical Na⁺–K⁺-ATPase specific activity and kinetics remained unchanged. Furthermore, experimentsin vitro failed to demonstrate a circulating inhibitor of renal Na⁺–K⁺-ATPase both in plasma dialysates from volume-expanded rats and in plasma dialysates concentrated 20-fold by ultrafiltration from volume-expanded dogs. These results suggest that the decreased proximal tubular reabsorption of sodium during volume expansion is not mediated by inhibition of renal cortical Na⁺–K⁺-ATPase. The acute increment in medullary Na⁺–K⁺-ATPase observed could represent an adaptive response to increased sodium reabsorption by the loops of Henle, and raises the possibility that this enzyme may participate in relatively rapid adjustments in the transport of sodium by the renal tubule.