Respiration physiology最新文献_第4页

Acid detection by taste receptor cells 味觉感受器细胞的酸检测

Respiration physiology Pub Date : 2001-12-01 DOI: 10.1016/S0034-5687(01)00293-6

John A. DeSimone , Vijay Lyall , Gerard L. Heck , George M. Feldman

{"title":"Acid detection by taste receptor cells","authors":"John A. DeSimone , Vijay Lyall , Gerard L. Heck , George M. Feldman","doi":"10.1016/S0034-5687(01)00293-6","DOIUrl":"10.1016/S0034-5687(01)00293-6","url":null,"abstract":"<div>Sourness is a primary taste quality that evokes an innate rejection response in humans and many other animals. Acidic stimuli are the unique sources of sour taste so a rejection response may serve to discourage ingestion of foods spoiled by acid producing microorganisms. The investigation of mechanisms by which acids excite taste receptor cells (TRCs) is complicated by wide species variability and within a species, apparently different mechanisms for strong and weak acids. The problem is further complicated by the fact that the receptor cells are polarized epithelial cells with different apical and basolateral membrane properties. The cellular mechanisms proposed for acid sensing in taste cells include, the direct blockage of apical K+ channels by protons, an H+-gated Ca2+ channel, proton conduction through apical amiloride-blockable Na+ channels, a Cl− conductance blocked by NPPB, the activation of the proton-gated channel, BNC-1, a member of the Na+ channel/degenerin super family, and by stimulus-evoked changes in intracellular pH. Acid-induced intracellular pH changes appear to be similar to those reported in other mammalian acid-sensing cells, such as type-I cells of the carotid body, and neurons found in the ventrolateral medulla, nucleus of the solitary tract, the medullary raphe, and the locus coceuleus. Like type-I carotid body cells and brainstem neurons, isolated TRCs demonstrate a linear relationship between intracellular pH (pHi) and extracellular pH (pHo) with slope, ΔpHi/ΔpHo near unity. Acid-sensing cells also appear to regulate pHi when intracellular pH changes occur under iso-extracellular pH conditions, but fail to regulate their pH when pHi changes are induced by decreasing extracellular pH. We shall discuss the current status of proposed acid-sensing taste mechanisms, emphasizing pH-tracking in receptor cells.</div>","PeriodicalId":20976,"journal":{"name":"Respiration physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0034-5687(01)00293-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75119554","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: 80

Central chemosensitivity and breathing asleep in unilateral medullary lesion patients: comparisons to animal data 单侧髓质病变患者的中枢化疗敏感性和睡眠呼吸:与动物数据的比较

Respiration physiology Pub Date : 2001-12-01 DOI: 10.1016/S0034-5687(01)00296-1

M.J Morrell , P Heywood , S.H Moosavi , J Stevens , A Guz

{"title":"Central chemosensitivity and breathing asleep in unilateral medullary lesion patients: comparisons to animal data","authors":"M.J Morrell , P Heywood , S.H Moosavi , J Stevens , A Guz","doi":"10.1016/S0034-5687(01)00296-1","DOIUrl":"10.1016/S0034-5687(01)00296-1","url":null,"abstract":"<div>The rostro-ventrolateral medulla (RVLM) is a site of chemosensitivity in animals; such site(s) have not been defined in humans. We studied the effect of unilateral focal lesions in the rostrolateral medulla (RLM) of man, on the ventilatory CO2 sensitivity and during awake and sleep breathing. Nine patients with RLM lesions (RLM group), and six with lesions elsewhere (non-RLM group) were studied. The ventilatory CO2 sensitivity was lower in the RLM compared with the non-RLM group (mean (S.D.), RLM, 1.4 (0.9), non-RLM 3.0 (0.6) L min−1 mmHg−1). In both groups resting breathing was normal. During sleep all RLM patients had frequent arousals, four had significant sleep disordered breathing (SDB), only one non-RLM patient had SDB. Our findings in humans resemble those in animals with focal RVLM lesions. This review provides evidence that in humans there is an area of chemosensitivity in the RLM. We propose that in humans, dorsal displacement of the RVLM area of chemosensitivity in animals, arises from development of the olive plus the consequences of the evolution of the cerebellum/inferior peduncle.</div>","PeriodicalId":20976,"journal":{"name":"Respiration physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0034-5687(01)00296-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78254763","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: 24

Chemoreceptive mechanisms elucidated by studies of congenital central hypoventilation syndrome 先天性中枢性低通气综合征的化学接受机制研究

Respiration physiology Pub Date : 2001-12-01 DOI: 10.1016/S0034-5687(01)00294-8

Christina M Spengler , David Gozal , Steven A Shea

{"title":"Chemoreceptive mechanisms elucidated by studies of congenital central hypoventilation syndrome","authors":"Christina M Spengler , David Gozal , Steven A Shea","doi":"10.1016/S0034-5687(01)00294-8","DOIUrl":"10.1016/S0034-5687(01)00294-8","url":null,"abstract":"<div>Humans born with the condition of central hypoventilation during non-rapid eye movement sleep, termed congenital central hypoventilation syndrome (CCHS), invariably have absent or greatly diminished central hypercapnic ventilatory chemosensitivity. Genetic and pathological studies of CCHS may enable identification of the genes or areas of the central nervous system involved in the syndrome and thus implicated in central hypercapnic ventilatory chemosensitivity. Functional studies of CCHS permit a more quantitative assessment of the importance of ventilatory chemosensitivity in the regulation of breathing during wakefulness and sleep. The experimental evidence suggests that central hypercapnic ventilatory chemosensitivity is crucial in regulating alveolar ventilation during non-rapid eye movement sleep but not during rapid eye movement sleep or during many of the behaviors occurring during wakefulness. Presumably, other neural drives to breathe supervene to enable adequate ventilation. However, although physiological studies in CCHS subjects have been greatly instructive, their accurate interpretation will have to await future determination of the potential genetic and/or neuroanatomic basis of the syndrome.</div>","PeriodicalId":20976,"journal":{"name":"Respiration physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0034-5687(01)00294-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76988012","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: 59

Monoaminergic neurons, chemosensation and arousal 单胺能神经元，化学感觉和觉醒

Respiration physiology Pub Date : 2001-12-01 DOI: 10.1016/S0034-5687(01)00290-0

M.A. Haxhiu , F. Tolentino-Silva , G. Pete , P. Kc , S.O. Mack

{"title":"Monoaminergic neurons, chemosensation and arousal","authors":"M.A. Haxhiu , F. Tolentino-Silva , G. Pete , P. Kc , S.O. Mack","doi":"10.1016/S0034-5687(01)00290-0","DOIUrl":"10.1016/S0034-5687(01)00290-0","url":null,"abstract":"<div>In recent years, immense progress has been made in understanding central chemosensitivity at the cellular and functional levels. Combining molecular biological techniques (early gene expression as an index of cell activation) with neurotransmitter immunohistochemistry, new information has been generated related to neurochemical coding in chemosensory cells. We found that CO2 exposure leads to activation of discrete cell groups along the neuraxis, including subsets of cells belonging to monoaminergic cells, noradrenaline-, serotonin-, and histamine-containing neurons. In part, they may play a modulatory role in the respiratory response to hypercapnia that could be related to their behavioral state control function. Activation of monoaminergic neurons by an increase in CO2/H+ could facilitate respiratory related motor discharge, particularly activity of upper airway dilating muscles. In addition, these neurons coordinate sympathetic and parasympathetic tone to visceral organs, and participate in adjustments of blood flow with the level of motor activity. Any deficit in CO2 chemosensitivity of a network composed of inter-related monoaminergic nuclei might lead to disfacilitation of motor outputs and to failure of neuroendocrine and homeostatic responses to life-threatening challenges (e.g. asphyxia) during sleep.</div>","PeriodicalId":20976,"journal":{"name":"Respiration physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0034-5687(01)00290-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81005246","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: 81

Central chemosensitivity, sleep, and wakefulness 中枢化学敏感性，睡眠和清醒

Respiration physiology Pub Date : 2001-12-01 DOI: 10.1016/S0034-5687(01)00295-X

Eugene E Nattie

{"title":"Central chemosensitivity, sleep, and wakefulness","authors":"Eugene E Nattie","doi":"10.1016/S0034-5687(01)00295-X","DOIUrl":"10.1016/S0034-5687(01)00295-X","url":null,"abstract":"<div>Neurons in many regions of the lower brain are chemosensitive in vitro. Focal acidification of these same and other regions in vivo can stimulate breathing indicating the presence of chemoreception. Why are there so many sites for central chemoreception? This review evaluates data obtained from unanesthetized rats at three central chemoreceptor sites, the retrotrapezoid nucleus (RTN), the medullary raphé, and the nucleus tractus solitarius (NTS) and extends ideas concerning two hypotheses, which were recently formulated (Nattie, E., 2000. Respir. Physiol. 122, 223–235). (1) The high overall sensitivity of the respiratory control system in the unanesthetized state to small increases in arterial CO2 relies on an additive or greater effect of these multiple chemoreceptor sites. (2) Chemoreceptor sites can vary in effectiveness dependent on the state of arousal. These ideas fit into a more speculative and general hypothesis that central chemoreceptors are organized in a hierarchical manner as proposed for temperature sensing and thermoregulation (Satinoff, E., 1978. Science 201, 16–22). The presence of a number of chemosensitive sites with varying thresholds, sensitivity, and arousal dependence provides finely tuned control and stability for breathing.</div>","PeriodicalId":20976,"journal":{"name":"Respiration physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0034-5687(01)00295-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90407206","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: 91

Central chemosensitivity of respiration: a brief overview 呼吸中枢化学敏感性:简要概述

Respiration physiology Pub Date : 2001-12-01 DOI: 10.1016/S0034-5687(01)00297-3

David Ballantyne, Peter Scheid

引用次数: 61

Central chemosensitivity of respiration: a brief overview. 呼吸中枢化学敏感性:简要概述。

Respiration physiology Pub Date : 2001-12-01 DOI: 10.1016/S0034-5687(01)00297-3

D. Ballantyne, P. Scheid

引用次数: 63

From low arterial- to low tissue-oxygenation strategy. An evolutionary theory 从低动脉氧合到低组织氧合策略。进化理论

Respiration physiology Pub Date : 2001-11-15 DOI: 10.1016/S0034-5687(01)00305-X

J.-C Massabuau

{"title":"From low arterial- to low tissue-oxygenation strategy. An evolutionary theory","authors":"J.-C Massabuau","doi":"10.1016/S0034-5687(01)00305-X","DOIUrl":"10.1016/S0034-5687(01)00305-X","url":null,"abstract":"<div>The primitive atmosphere where aerobic life started on earth was hypoxic and hypercapnic. Remarkably, an adaptation strategy whereby O2 partial pressure, PO2, in the arterial blood is maintained within a low and narrow range of 1–3 kPa, largely independent of inspired PO2, has also been reported in modern water-breathers. In mammalian tissues, including brain, the most frequently measured PO2 is in the same low range. Based on the postulate that basic cellular machinery has been established since the early stages of evolution, we propose that this similarity in oxygenation status is the consequence of an early adaptation strategy which, subsequently throughout the course of evolution, maintained cellular oxygenation in the same low and primitive range independent of environmental changes. The rational for such an evolutionary theory is discussed in terms of an equilibrium between physiological and pathological reactions associated with O2 excess vs O2 lack and emerging concepts about the importance of cellular O2-dependent mechanisms in the low but physiological PO2 range.</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)00305-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77129705","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: 72

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

Andrew P Wickens

{"title":"Ageing and the free radical theory","authors":"Andrew P Wickens","doi":"10.1016/S0034-5687(01)00313-9","DOIUrl":"https://doi.org/10.1016/S0034-5687(01)00313-9","url":null,"abstract":"<div>The free radical theory proposes that ageing is the cumulative result of oxidative damage to the cells and tissues of the body that arises primarily as a result of aerobic metabolism. Several lines of evidence have been used to support this hypothesis including the claims that: (1) variation in species life span is correlated with metabolic rate and protective antioxidant activity; (2) enhanced expression of antioxidative enzymes in experimental animals can produce a significant increase in longevity; (3) cellular levels of free radical damage increases with age; and (4) reduced calorie intake leads to a decline in the production of reactive oxygen species and an increase in life span. The free radical theory may also be used to explain many of the structural features that develop with ageing including the lipid peroxidation of membranes, formation of age pigments, cross-linkage of proteins, DNA damage and decline of mitochondrial function. Despite this, many uncertainties concerning the role of oxidative damage in ageing remain and alternative explanations cannot be ruled out. Free radicals only occur in trace quantities in biological tissues, their cellular levels and actions cannot be measured in vivo, and definitive proof that oxidised molecules are the primary cause of ageing is lacking. Moreover, ageing is also likely to be a multifactorial process and not reducible to any one single cause. Thus, despite its positive features, the evidence for the free radical theory is either correlative or inconclusive.</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)00313-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91743755","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: 527

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

T. Porwol, W. Ehleben, V. Brand, H. Acker

引用次数: 56