Abstract:
:We recently reported that a higher percentage of type I fibres in vastus lateralis and a greater peak oxygen uptake (O2) were associated with a greater initial rise in O2 (O2 /W, where W is work rate) following the onset of heavy constant power output exercise (above the lactate threshold, LT). It was unclear if these results were true only for heavy exercise, or if the association between fibre type and/or fitness and O2 /W would also be seen for moderate (< LT) exercise. The purpose of the present study was to compare the relationships between fibre type or peak O2 and O2 /W determined for moderate (< LT) and heavy (> LT) exercise intensities during incremental exercise. Nine healthy subjects performed an incremental ramp test on a cycle ergometer. The O2 /Wslope was calculated for the domain of power outputs up to the LT (S1), from the LT towards peak O2 (S2), and over the entire linear portion of the O2 /W response (ST), and compared to fibre type distribution determined from biopsy of the vastus lateralis, and to peak O2 (as ml kg-1 min-1). Significant correlations between O2 /W and the proportion of type I fibres were found for each exercise domain (r is 0.69, 0.71 and 0.84 for S1, S2 and ST, respectively, P < 0.05). S1 ranged between about 9 ml min-1 W-1 for a low proportion of type I fibres and 11 ml min-1 W-1 for a high proportion of type I fibres. Similar correlations were also found between S2 (r = 0.70) and ST (r = 0.76) and peak O2. These results are consistent with our previous findings during > LT constant power output exercise, and suggest that the proportion of type I fibres, and possibly fitness as indicated by peak O2, is associated with greater O2 /W during the initial adjustment to < LT as well as > LT exercise. These results do not appear to be explained by classical descriptions of the kinetics of adjustment of O2 following the onset of ramp or constant power output exercise. They might reflect enhanced motor unit recruitment in subjects with a greater percentage of type I fibres, and/or who are more aerobically fit. However, the underlying mechanism for these findings must await further study.
journal_name
Exp Physioljournal_title
Experimental physiologyauthors
Barstow TJ,Jones AM,Nguyen PH,Casaburi Rsubject
Has Abstractpub_date
2000-01-01 00:00:00pages
109-16issue
1eissn
0958-0670issn
1469-445Xpii
PHY_1942journal_volume
85pub_type
临床试验,杂志文章abstract::The effects on vasopressin and cortisol secretion of centrally and peripherally administered cholecystokinin octapeptide (CCK) were investigated in conscious prepubertal pigs. Injection of 1.3 micrograms CCK into the lateral cerebral ventricle resulted in a sustained increase in plasma vasopressin after a latency of 5...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1991.sp003518
更新日期:1991-07-01 00:00:00
abstract::Hypertension caused by chronic infusion of angiotensin II (Ang II) in experimental animals is dependent, in part, on increased activity of the sympathetic nervous system. This chronic sympathoexcitatory response is amplified by a high-salt diet, suggesting an interaction of circulating Ang II and dietary salt on sympa...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2011.060491
更新日期:2012-01-01 00:00:00
abstract::This study investigated whether sensitivity to nociceptive stimuli is altered in obese rats using established models of inflammatory pain, and using real-time PCR, profiled alterations in expression of key adipokine and inflammatory mediator mRNA (adiponectin, tumor necrosis factor-α, interleukin-1β, cyclooxygenase-2,...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2011.064220
更新日期:2012-11-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? What is the role of miR-143-3p during human dental pulp stem cell (hDPSC) differentiation. What is the main finding and its importance? miR-143-3p negatively regulates receptor activator of nuclear factor-κB (RANK). RANK ligand (RANKL) binds to RANK and stimulate...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP087992
更新日期:2020-05-01 00:00:00
abstract::The responses of afferent chemosensory fibres of the carotid body to individual chemostimuli have long been established. However, the mechanisms underlying the multiplicative interactions of these stimuli (i.e. how the combined effects of hypoxia and hypercapnia exert a greater effect on afferent nerve discharge than ...
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/expphysiol.2003.002657
更新日期:2004-01-01 00:00:00
abstract::Previous studies have shown that prolactin administration to pregnant rats results in offspring with enhanced abundance of the brown adipose tissue-specific uncoupling protein (UCP) 1. The present study therefore aimed to determine whether a similar effect was observed after birth and if the sex of the animal further ...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/eph8802575
更新日期:2003-07-01 00:00:00
abstract::Recently attempts have been made to analyse blood pressure (BP) and renal sympathetic nerve activity (RSNA) to determine how patterns contained within them might reflect control by the autonomic nervous system. To date, these studies have primarily used coherence analysis of BP and RSNA in the frequency domain. Howeve...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1111/j.1469-445x.2002.tb00059.x
更新日期:2002-07-01 00:00:00
abstract::Using the patch-clamp recording technique, we observed that endothelin-1 (ET-1; 0.8-16 nM) enhanced a voltage-activated outward current (Iout) and induced periodic oscillations of inward current in smooth muscle cells isolated from small pulmonary arteries (200-400 microns in diameter). Anion substitution experiments ...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1995.sp003889
更新日期:1995-09-01 00:00:00
abstract::Indirect evidence supporting a solute-coupled liquid absorption from the pleural space of rabbits has recently been provided; moreover, the beta 2-adrenoceptor agonist terbutaline has been found to increase this absorption. In this study the effect of adrenaline and alpha-adrenoceptor agonists on net rate of liquid ab...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1997.sp004043
更新日期:1997-05-01 00:00:00
abstract::Progressive asphyxia, produced by a prolonged voluntary breath hold (end-expiratory apnoea), evokes large bursts of muscle sympathetic nerve activity (MSNA). These bursts increase in amplitude until the asphyxic break point is reached, at which point the bursts are inhibited. We tested the hypothesis that lung inflati...
journal_title:Experimental physiology
pub_type: 杂志文章,随机对照试验
doi:10.1113/expphysiol.2012.067421
更新日期:2013-02-01 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::The aim of this study was to determine the ouabain receptor density, Na+,K(+)-ATPase function and contractile properties of cardiac muscle in insulin-dependent and non-insulin-dependent rat diabetes mellitus (IDDM and NIDDM, respectively) and the reversibility of the diabetes-induced changes by insulin or thyroxin sub...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1998.sp004092
更新日期:1998-01-01 00:00:00
abstract::Neural mediation of the human cardiac response to isocapnic (IC) steady-state hypoxaemia was investigated using coarse-graining spectral analysis of heart rate variability (HRV). Six young adults were exposed in random order to a hypoxia or control protocol, in supine and sitting postures, while end-tidal PCO2 (PET,CO...
journal_title:Experimental physiology
pub_type: 临床试验,杂志文章,随机对照试验
doi:
更新日期:2000-03-01 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::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::Phosphoethanolamine and taurine have been identified in uterine extracts from rat and, for the first time, human tissue. The concentration of phosphoethanolamine [PEtn] determined by HPLC and 31P NMR spectroscopy, increased markedly (40%) within the first 6-12 h following parturition in rats, suggesting a role in invo...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1994.sp003794
更新日期:1994-07-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? Clinical reports have described and suggested central and peripheral respiratory abnormalities in Parkinson's disease (PD) patients; however, these reports have never addressed the occurrence of these abnormalities in an animal model. What is the main finding and...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP087507
更新日期:2019-05-01 00:00:00
abstract::We have examined the effect of a hyposmotic shock, and thus cell swelling, upon the efflux of amino acids, SO4(2-) and I- from lactating mammary tissue. A hyposmotic challenge increased the efflux of taurine and glycine via a 4,4'-diisothiocyanatostilbene-2,2'- disulphonic acid (DIDS)-sensitive pathway. It appears tha...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1994.sp003808
更新日期:1994-09-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? What is the carotid bodies' contribution to active inspiratory and expiratory response to exercise? What is the main finding and its importance? Removal of the carotid bodies reduced the active inspiratory and expiratory responses of diaphragm and abdominal inter...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP088203
更新日期:2020-08-01 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::The application of the four main techniques available for examining the properties of alpha-adrenoceptors, gene coding, radioligand, biochemical and functional methods, has reinforced the earlier subclassification (alpha 1- and alpha 2-subtypes). These different techniques have not yet yielded subclassifications which...
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/expphysiol.1991.sp003501
更新日期:1991-05-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? Does 14 days of live-high, train-low simulated altitude alter an individual's metabolomic/metabolic profile? What is the main finding and its importance? This study demonstrated that ∼200 h of moderate simulated altitude exposure resulted in greater variance in m...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP087159
更新日期:2019-01-01 00:00:00
abstract::In the present study, we tested the hypothesis that chronic intermittent hypoxia (CIH) produces changes in the autonomic and respiratory responses to acute peripheral chemoreflex activation. To attain this goal, 3-week-old rats were exposed to 10 days of CIH (6% O(2) for 40 s at 9 min intervals; 8 h day(-1)). They wer...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2006.034868
更新日期:2006-11-01 00:00:00
abstract::The aims of this study were: (1) to determine the within-subject, between-day variability in end-tidal P(CO2) (P(ET,CO2)); (2) to determine whether the within-subject, between-day variability in P(ET,CO2) was caused by variations in metabolic acid-base status; and (3) to determine whether between-subject variations in...
journal_title:Experimental physiology
pub_type: 临床试验,杂志文章
doi:10.1113/eph8802585
更新日期:2003-09-01 00:00:00
abstract::Plasticity of insulin secretion is essential to maintain the action of insulin during insulin resistance and to prevent diabetes. Investigation of the plasticity of insulin secretion and its regulation is challenging, and the objective of this study was to develop a novel large-animal-based model. The effect of chroni...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2011.063560
更新日期:2012-05-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? β-Adrenergic receptor activation modulates cutaneous vasodilatation and sweating in young adults. In this study, we assessed whether age-related differences in β-adrenergic regulation of these responses exist and whether they differ between men and women. What is...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP088583
更新日期:2020-10-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? We examined whether the macrophage-synthesized antioxidant 7,8-dihydroneopterin was elevated in Duchenne muscular dystrophy (DMD) patients. We then examined whether 7,8-dihydroneopterin could protect dystrophic skeletal mouse muscle from eccentric contraction-ind...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP087031
更新日期:2018-07-01 00:00:00
abstract::Gastric motility was recorded from ferrets chronically prepared with an antral strain gauge. In fasted animals, antral motility showed cycles of activity and quiescence typical of the migrating motor complex (MMC) with a period of 44.7 +/- 6.1 min (n = 4). Anaesthesia with pentobarbitone sodium (50 mg/kg) disrupted th...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1990.sp003448
更新日期:1990-09-01 00:00:00
abstract::Three experiments were performed to see whether cardiac neurons contribute to the intrinsic control of heart rate in right atria of adult rats. The intrinsic heart rate response (IRR) was examined by raising right atrial pressure from 2 to 8 mmHg for 3 min. In isolated preparations of the right atrium, the IRR was not...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/eph8702364
更新日期:2002-11-01 00:00:00
abstract:NEW FINDINGS:What is the topic of this review? One of the major unanswered questions in physiology is that of how breathing matches metabolic rate. Venous chemoreceptors seem to have been dismissed since the 1960s. What advances does it highlight? New evidence shows that their apparent dismissal needs reappraisal. The ...
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/EP086561
更新日期:2017-12-01 00:00:00