Abstract:
:Lower body negative pressure (LBNP) reduces central venous pressure (CVP) and cardiac output. The elderly are reported to have a limited capacity to increase cardiac output by increasing heart rate (HR), are especially dependent on end diastolic volume to maintain stroke volume and therefore should be especially vulnerable to LBNP. The present study compared the effects of LBNP in the young and old. Stroke volume was assessed non-invasively as stroke distance (SD) by aortovelography. Two groups of healthy male volunteers were studied: eight young (29.7 +/- 2.0 years, mean +/- S.E.M.) and nine old (70.1 +/- 0.9 years). LBNP was applied progressively at 17.5, 35 and 50 mmHg in 20 min steps, with measurements taken during each steady state. There were similar, significant, falls in CVP in both groups. SD fell significantly in both groups from respective control values of 24.8 +/- 1.6 and 16.6 +/- 0.9 cm to 12.5 +/- 1.3 and 8.9 +/- 0.4 cm at a LBNP of 50 mmHg. Although SD in the elderly was significantly lower than in the young, the LBNP-induced changes were not different between groups. Both groups produced similar significant increases in vascular resistance, HR, plasma vasopressin (AVP) and noradrenaline. Mean arterial blood pressure (MBP) and plasma adrenaline did not change significantly. Therefore healthy old men respond to LBNP in a similar manner to the young, although MBP and SD are regulated around different baselines in the two groups.
journal_name
Exp Physioljournal_title
Experimental physiologyauthors
van Hoeyweghen R,Hanson J,Stewart MJ,Dethune L,Davies I,Little RA,Horan MA,Kirkman Edoi
10.1113/eph8602153subject
Has Abstractpub_date
2001-05-01 00:00:00pages
427-35issue
3eissn
0958-0670issn
1469-445Xpii
EPH_2153journal_volume
86pub_type
杂志文章abstract:NEW FINDINGS:What is the topic of this review? This review concerns the negative impact of pulmonary hypertension (PH) on the pulmonary haemodynamic and gas exchange responses to exercise, considering the mechanisms by which PH plays a role in exercise intolerance in heart failure (HF) patients. What advances does it h...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP088105
更新日期:2020-02-24 00:00:00
abstract::Pairs of Ia and II afferent fibres supplying primary and secondary endings lying in the same tenuissimus spindles were prepared in barbiturate anaesthetized cats in order to compare the variability in the rhythm of discharge of the two endings during responses elicited by the contraction of different intrafusal muscle...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1994.sp003801
更新日期:1994-09-01 00:00:00
abstract:NEW FINDINGS:What is the topic of this review? This review provides a comprehensive overview of Nox5 from basic biology to human disease and highlights unique features of this Nox isoform What advances does it highlight? Major advances in Nox5 biology relate to crystallization of the molecule and new insights into the ...
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/EP086204
更新日期:2019-05-01 00:00:00
abstract::Latex beads coated with secretory immunoglobulin (IgA) instilled into mouse intestinal loops are taken up by M cells present in Peyer's patch follicle-associated epithelial tissue. Bead adsorption and uptake is greater at the edge compared with the apex of follicle domes. Coating beads with bovine serum albumin (BSA) ...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1992.sp003662
更新日期:1992-11-01 00:00:00
abstract::Altered systemic haemodynamics following exercise can compromise cerebral perfusion and result in syncope. As the Wingate anaerobic test often induces presyncope, we hypothesized that a modified Wingate test could form the basis of a novel model for the study of postexercise syncope and a test bed for potential counte...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2013.075333
更新日期:2014-01-01 00:00:00
abstract::The present study was designed to analyse the effects of aerobic exercise on the metabolic effects of alloxan. Male Wistar newborn rats (2 days old) received alloxan (200 mg (kg body weight)(-1)) intraperitoneally (A rats). Vehicle-injected rats were used as controls (C rats). At 28 days old, some of the A rats were s...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2004.028241
更新日期:2005-01-01 00:00:00
abstract::Flow of submandibular saliva and the constituents secreted during chorda-lingual nerve stimulation at 40 Hz (3 x 10 min) were studied after alpha- and beta-adrenergic blockade, and in the absence (control) or presence of cholinergic blockade in anaesthetized rats. Peroxidase and true tissue kallikrein (rK1) were asses...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1996.sp003940
更新日期:1996-05-01 00:00:00
abstract::The results of this investigation demonstrate, using a position matching paradigm, that the ability of subjects to detect changes in the position of the proximal interphalangeal joint is impaired in patients with rheumatoid arthritis affecting this joint. In this group there is a systematic flexion bias in position ju...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1992.sp003633
更新日期:1992-09-01 00:00:00
abstract::Growing lambs fed a diet containing NaHCO3 were made acidotic by intravenously infusing HCl at the rate of 1 mmol/min over a 4 h period. Acid infusion led to a fall in blood and urine pH and a prompt increase in urinary Ca excretion. This in turn led to a fall in plasma Ca concentration and a rise in parathyroid hormo...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1993.sp003676
更新日期:1993-03-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? Is lower body negative pressure a useful surrogate to study white blood cell responses to haemorrhage in humans? What is the main finding and its importance? We found that lower body negative pressure appears to be a useful surrogate to study the early white bloo...
journal_title:Experimental physiology
pub_type: 杂志文章,随机对照试验
doi:10.1113/EP085952
更新日期:2016-10-01 00:00:00
abstract::Tumour cell survival is intimately related to blood vessel function and so the tumour vasculature represents a novel target for cancer therapy. We have investigated a murine tumour model in which a metal clamp was used to occlude the vascular supply temporarily and then removed to allow reperfusion. This allows the st...
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/expphysiol.1997.sp004031
更新日期:1997-03-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? Does sex or neonatal stress affect the expression of pituitary adenylate cyclase-activating peptide or its receptors? What is the main finding and its importance? Neonatal-maternal separation stress has little long-lasting effect on the expression of pituitary ad...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2014.082180
更新日期:2015-02-01 00:00:00
abstract::There is controversy about the effect of left ventricular pressure on resistance of the intramyocardial coronary vessels. In anaesthetized dogs the effect of left ventricular pressure on coronary flow during diastole was studied using an extracorporeal circulation and allowing the heart to contract and relax isovolumi...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1992.sp003602
更新日期:1992-03-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? What is the precise subcellular localization of the epithelial sodium channel (ENaC) in human airway epithelium? What is the main finding and its importance? ENaC protein has an unexpected localization in the peripheral region of the apical membrane of bronchial ...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP087590
更新日期:2019-06-01 00:00:00
abstract::The renal medulla contains more mRNA of the inducible isoform of nitric oxide synthase (iNOS) than the cortex, which may be important in preventing ischaemic injury, since blood flow and tissue oxygen tension are normally low in this region. We examined the effects of the bacterial endotoxin E. coli lipopolysaccharide...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/eph8702289
更新日期:2002-03-01 00:00:00
abstract::Exposure to whole-body vibration is implicated as one of the occupational risk factors for lower back disorders; however, its influence on the lumbar muscle physiology is still poorly understood. The objective of this study was to investigate the effects of backrest support and hand grip contractions on lumbar muscle ...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2006.033696
更新日期:2006-09-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? Do the pulmonary vascular responses to hypoxia change during progressive exposure to high altitude and can alterations in these responses be related to changes in concentrations of circulating biomarkers that affect the pulmonary circulation? What is the main fin...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP086083
更新日期:2017-06-01 00:00:00
abstract::A method is described that enables the cell membrane of isolated rat ventricular myocytes to be permeabilized and resealed while maintaining cell viability. Streptolysin O, a cholesterol-binding cytolysin, was used to form pores in the surface membrane; subsequent incubation with 5% fetal bovine serum was used to reve...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1998.sp004114
更新日期:1998-05-01 00:00:00
abstract:NEW FINDINGS:What is the topic of this review? The sympathetic control of renal sodium tubular reabsorption is dependent on activation of the intrarenal renin-angiotensin system and activation of the angiotensin II type 1 (AT1 ) receptor by angiotensin II. What advances does it highlight? Despite the fact that the inte...
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/EP085075
更新日期:2015-04-20 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? What are the cellular and molecular determinants of increased risk for cardiovascular disease from prolonged sitting? What is the main finding and its importance? Prolonged sitting, independent of calf raise interruption strategies, decreases microparticle counts...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP088690
更新日期:2020-08-01 00:00:00
abstract::Therapeutic angiogenesis/vasculogenesis holds promise for the cure of ischaemic disease. The approach postulates the manipulation of spontaneous healing response by supplementation of growth factors or transplantation of vascular progenitor cells. These supplements are intended to foster the formation of arterial coll...
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/expphysiol.2004.028571
更新日期:2005-05-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? The central goal of this study was to elucidate the role of magnesium in the regulation of pulmonary vascular reactivity in relationship to hypoxic pulmonary hypertension. What is the main finding and its importance? We found that magnesium is essential for norma...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP086655
更新日期:2018-04-01 00:00:00
abstract::Preparations of isolated rat jejunal enterocyte and brush-border and basolateral membrane vesicles have been used to study the effects of a 15 min exposure of upper and mid-villus enterocytes to pancreatic glucagon on the initial, unidirectional phlorhizin-sensitive (brush border) transport of galactose and phlorhizin...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1993.sp003680
更新日期:1993-03-01 00:00:00
abstract::In anaesthetized cats, reflex respiratory responses were evoked by electrically stimulating proximal ends of cut nerves to gastrocnemius-soleus muscles of the left hindlimb. The direction of these responses, in the excitatory or inhibitory sense, depended on the types of afferent fibres stimulated and on the mode of s...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1995.sp003826
更新日期:1995-01-01 00:00:00
abstract::Endothelium-dependent relaxation in response to histamine and ACh has been studied on precontracted aortic rings from control and salt-loaded Sprague-Dawley rats. Both ACh and histamine caused relaxation of the noradrenaline-induced precontraction only in the presence of the endothelium. The relaxation response to ACh...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1991.sp003475
更新日期:1991-01-01 00:00:00
abstract:NEW FINDINGS:What is the topic of this review? This brief review discusses potential sex differences in arterial function across the age span, with special emphasis on the effects of oestrogen and testosterone on the vascular endothelium. What advances does it highlight? We discuss the relationship between the impacts ...
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/EP085367
更新日期:2016-02-01 00:00:00
abstract::Arterial pressure is regulated over long periods of time by neural, hormonal and local control mechanisms, which ultimately determine the total blood volume and how it is distributed between the various vascular compartments of the circulation. A full understanding of the complex interplay of these mechanisms can be g...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2008.043281
更新日期:2009-04-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? Does the combination of methazolamide and theophylline reduce symptoms of acute mountain sickness (AMS) and improve aerobic performance in acute hypobaric hypoxia? What is the main finding and its importance? The oral combination of methazolamide (100 BID) and th...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP088461
更新日期:2021-01-01 00:00:00
abstract::Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women, with a prevalence of 8-12% during the reproductive years. In the present study, using prenatal exposure to a single dose of testosterone during the critical period of fetal development, we aimed to introduce an enhanced rat model ...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2014.078055
更新日期:2014-05-01 00:00:00
abstract::What is the central question of this study? Failure to terminate apnoea and arouse is likely to contribute to sudden infant death syndrome (SIDS). Serotonin is deficient in the brainstems of babies who died of SIDS. Therefore, we tested the hypothesis that serotonin in the nucleus of the solitary tract (NTS) would sho...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP085716
更新日期:2016-07-01 00:00:00