Respiration physiology最新文献_第5页

Mechanisms of metabolic defense against hypoxia in hibernating frogs 冬眠蛙对缺氧的代谢防御机制

Respiration physiology Pub Date : 2001-11-15 DOI: 10.1016/S0034-5687(01)00312-7

Robert G Boutilier

{"title":"Mechanisms of metabolic defense against hypoxia in hibernating frogs","authors":"Robert G Boutilier","doi":"10.1016/S0034-5687(01)00312-7","DOIUrl":"https://doi.org/10.1016/S0034-5687(01)00312-7","url":null,"abstract":"<div>The cold submerged frog (Rana temporaria) serves as a useful model for many hibernating ectotherms that take refuge in hypoxic ponds and lakes until more favourable conditions of climate and food availability return. In all such animals, entry into a hypometabolic state effectively extends their survival time by lessening the impact of ATP demands on endogenous substrates. At the cellular level, metabolic depression may be brought about by decreasing energy-consuming processes and/or by increasing the efficiency of energy-producing pathways. Since the mitochondrion is the major contributor to the total energy production during aerobic metabolism and frog survival during winter depends on entry into a hypometabolic state, this review focuses on the respiratory properties of mitochondria that serve to increase the efficiency of energy production in hibernation. Energy conservation during overwintering also occurs through decreases in the ATP demand of the energy-consuming processes. For example, hibernating frogs decrease their ATP demands for Na+/K+-ATPase activity as part of a coordinated process of energy conservation wherein O2-limitation initiates a generalised suppression of ion channel densities and/or channel leak activities. The net result is that cell membrane permeabilities are reduced, thereby lowering the energetic costs of maintaining transmembrane ion gradients.</div>","PeriodicalId":20976,"journal":{"name":"Respiration physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0034-5687(01)00312-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91743756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 52

Aging and oxidative stress: studies of some genes involved both in aging and in response to oxidative stress 衰老和氧化应激:研究衰老和氧化应激反应中涉及的一些基因

Respiration physiology Pub Date : 2001-11-15 DOI: 10.1016/S0034-5687(01)00314-0

Nadine Camougrand, Michel Rigoulet

引用次数: 104

Bioenergetics at low oxygen: dependence of respiration and phosphorylation on oxygen and adenosine diphosphate supply 低氧下的生物能量学:呼吸和磷酸化对氧和二磷酸腺苷供应的依赖

Respiration physiology Pub Date : 2001-11-15 DOI: 10.1016/S0034-5687(01)00307-3

Erich Gnaiger

{"title":"Bioenergetics at low oxygen: dependence of respiration and phosphorylation on oxygen and adenosine diphosphate supply","authors":"Erich Gnaiger","doi":"10.1016/S0034-5687(01)00307-3","DOIUrl":"10.1016/S0034-5687(01)00307-3","url":null,"abstract":"<div>Oxygen limitation is generally considered as impairment of mitochondrial respiration under hypoxia and ischemia. Low intracellular oxygen levels under normoxia, however, imply mild oxygen limitation, provide protection from oxidative stress, and result from economical strategies for oxygen transport through the respiratory cascade to cytochrome c oxidase. Both perspectives relate to the critical oxygen pressure, which inhibits mitochondrial respiration. Based on methodological considerations of oxygen kinetics and a presentation of high-resolution respirometry, mitochondrial oxygen affinities (1/P50) are reviewed with particular emphasis on the turnover effect under control of adenosine diphosphate ADP concentration, which increases the P50 in active states. ADP/O2 flux ratios are high even under severe oxygen limitation, as demonstrated by calorespirometry. Oxygen limitation reduces the uncoupled respiration observed under control by ADP, as shown by relationships derived between ADP/O2 flux ratios, respiratory control ratios, and ADP kinetics. Bioenergetics at low oxygen versus oxidative stress must be considered in the context of limitation of maximum aerobic activity, ischemia-reperfusion injury, mitochondrial signalling to apoptosis, and mitochondrial theories of ageing.</div>","PeriodicalId":20976,"journal":{"name":"Respiration physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0034-5687(01)00307-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78264695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 279

Ageing and the free radical theory. 衰老和自由基理论。

Respiration physiology Pub Date : 2001-11-15 DOI: 10.1016/S0034-5687(01)00313-9

A. Wickens

引用次数: 537

Tissue oxygen sensor function of NADPH oxidase isoforms, an unusual cytochrome aa3 and reactive oxygen species 组织氧传感器的功能NADPH氧化酶异构体，一个不寻常的细胞色素aa3和活性氧

Respiration physiology Pub Date : 2001-11-15 DOI: 10.1016/S0034-5687(01)00310-3

Torsten Porwol, Wilhelm Ehleben, Verena Brand, Helmut Acker

引用次数: 56

Aging and oxidative stress: studies of some genes involved both in aging and in response to oxidative stress. 衰老和氧化应激:研究衰老和氧化应激反应中涉及的一些基因。

Respiration physiology Pub Date : 2001-11-15 DOI: 10.1016/S0034-5687(01)00314-0

N. Camougrand, M. Rigoulet

引用次数: 106

Respiratory and circulatory compensation to hypoxia in crustaceans 甲壳类动物对缺氧的呼吸和循环补偿

Respiration physiology Pub Date : 2001-11-15 DOI: 10.1016/S0034-5687(01)00311-5

Brian R McMahon

{"title":"Respiratory and circulatory compensation to hypoxia in crustaceans","authors":"Brian R McMahon","doi":"10.1016/S0034-5687(01)00311-5","DOIUrl":"https://doi.org/10.1016/S0034-5687(01)00311-5","url":null,"abstract":"<div>Crustaceans are often tolerant of hypoxic exposure and many regulate O2 consumption at low ambient O2. In acute hypoxia, most increase branchial water flow, and many also increase branchial haemolymph flow, both by an increase in cardiac output and by shunting flow away from the viscera. The O2-binding affinity of crustacean O2 carriers increases in hypoxic conditions, as a result of hyperventilation induced alkalosis. In chronic hypoxic exposure some crustaceans do not sustain high ventilatory pumping levels but increased effectiveness of O2-uptake across the gills is maintained as a result of the build up of metabolites such as lactate and urate which also function to increase the haemocyanin O2-binding affinity. Chronic exposure to hypoxia also may increase O2-binding capacity and promote the synthesis of new high O2-affinity carrier molecules. Exposure to untenable rates or levels of O2 depletion causes many decapodan crustaceans to surface and ventilate the gills with air. Burrowing crayfish provide an example of animals, which excel in all these mechanisms. Control mechanisms involved in compensatory responses to hypoxia are discussed.</div>","PeriodicalId":20976,"journal":{"name":"Respiration physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0034-5687(01)00311-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91743757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 160

Mechanisms of metabolic defense against hypoxia in hibernating frogs. 冬眠蛙对缺氧的代谢防御机制。

Respiration physiology Pub Date : 2001-11-15 DOI: 10.1016/S0034-5687(01)00312-7

R. Boutilier

引用次数: 52

Tissue oxygen tension and brain sensitivity to hypoxia 组织氧张力和大脑对缺氧的敏感性

Respiration physiology Pub Date : 2001-11-15 DOI: 10.1016/S0034-5687(01)00306-1

Maria Erecińska, Ian A. Silver

{"title":"Tissue oxygen tension and brain sensitivity to hypoxia","authors":"Maria Erecińska, Ian A. Silver","doi":"10.1016/S0034-5687(01)00306-1","DOIUrl":"10.1016/S0034-5687(01)00306-1","url":null,"abstract":"<div>Mammalian brain is a highly oxidative organ and although it constitutes only a small fraction of total body weight it accounts for a disproportionately large percentage of bodily oxygen consumption (in humans about 2 and 20%, respectively). Yet, the partial pressure and concentration of oxygen in the brain are low and non-uniform. There is a large number of enzymes that use O2 as a substrate, the most important of which is cytochrome c oxidase, the key to mitochondrial ATP production. The affinity of cytochrome c oxidase for oxygen is very high, which under normal conditions ensures undiminished activity of oxidative phosphorylation down to very low PO2. By contrast, many other relevant enzymes have Km values for oxygen within, or above, the ambient cerebral gas tension, thus making their operations very dependent on oxygen level in the physiological range. Among its multiple, versatile functions, oxygen partial pressure and concentration control production of reactive oxygen species, expression of genes and functions of ion channels. Limitation of oxygen supply to the brain below a ‘critical’ level reduces, and eventually blocks oxidative phosphorylation, drastically decreases cellular (ATP) and leads to a collapse of ion gradients. Neuronal activity ceases and if oxygen is not re-introduced quickly, cells die. The object of this review is to discuss briefly the central oxygen-dependent processes in mammalian brain and the short-term consequences of O2 deprivation, but not the mechanisms of long-term adaptation to chronic hypoxia. Particular emphasis is placed on issues which have been the focus of recent attention and/or controversy.</div>","PeriodicalId":20976,"journal":{"name":"Respiration physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0034-5687(01)00306-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88808341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 577

Haemoglobin function in vertebrates: evolutionary changes in cellular regulation in hypoxia 脊椎动物血红蛋白功能:缺氧时细胞调节的进化变化

Respiration physiology Pub Date : 2001-11-15 DOI: 10.1016/S0034-5687(01)00309-7

Mikko Nikinmaa

{"title":"Haemoglobin function in vertebrates: evolutionary changes in cellular regulation in hypoxia","authors":"Mikko Nikinmaa","doi":"10.1016/S0034-5687(01)00309-7","DOIUrl":"10.1016/S0034-5687(01)00309-7","url":null,"abstract":"<div>The evolution of erythrocytic hypoxia responses is reviewed by comparing the cellular control of haemoglobin-oxygen affinity in agnathans, teleost fish and terrestrial vertebrates. The most ancient response to hypoxic conditions appears to be an increase in cell volume, which increases the haemoglobin-oxygen affinity in lampreys. In teleost fish, an increase of cell volume in hypoxic conditions is also evident. The volume increase is coupled to an increase in erythrocyte pH. These changes are caused by an adrenergic activation of sodium/proton exchange across the erythrocyte membrane. The mechanism is important in acute hypoxia and is followed by a decrease in cellular adenosine triphosphate (ATP) and guanosine triphosphate (GTP) concentrations in continued hypoxia. In hypoxic bird embryos, the ATP levels are also reduced. The mechanisms by which hypoxia decreases cellular ATP and GTP concentrations remains unknown, although at least in bird embryos cAMP-dependent mechanisms have been implicated. In mammals, hypoxia responses appear to occur mainly via modulation of cellular organic phosphate concentrations. In moderate hypoxia, 2,3-diphosphoglycerate levels are increased as a result of alkalosis caused by increased ventilation.</div>","PeriodicalId":20976,"journal":{"name":"Respiration physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0034-5687(01)00309-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87593525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 86