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Cardiovascular Adaptation (cardiovascular + adaptation)
Selected AbstractsUroguanylin level in umbilical cord bloodPEDIATRICS INTERNATIONAL, Issue 3 2001Hirokazu Tsukahara Abstract Background: Uroguanylin is a novel natriuretic and diuretic peptide originally isolated from urine. Methods: To determine whether uroguanylin has a physiologic role during the perinatal period, uroguanylin levels in umbilical cord plasma obtained at the time of delivery were measured by radioimmunoassay and compared with cord serum osmolality. Results: Mean (±SD) cord plasma uroguanylin concentrations (8.8±2.1 fmol/mL) were higher compared with normal adult values. The extent of maturity, mode of delivery and gender did not appear to influence cord uroguanylin levels. The uroguanylin concentration had a significant positive correlation with cord serum osmolality. Conclusion: These findings support some regulatory role of this peptide in perinatal renal and cardiovascular adaptation. [source] Developmental adaptation: Where we go from here,AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2009A. Roberto Frisancho The concept of developmental adaptation is a powerful framework that can be used for understanding the origin of population differences in phenotypic and genotypic biological traits. There is great deal of information describing how developmental responses can shape adult biological outcomes. Specifically, current research suggest that individuals developing in stressful environments such as high altitude will attain an adult enlarged residual lung volume that contribute to the successful cardiovascular adaptation of the high-altitude Andean native. Likewise, studies on the etiology of the metabolic syndrome indicate that development under poor nutritional environments elicit efficient physiological and metabolic responses for the utilization of nutrients and energy, which become disadvantageous when the adult environmental conditions provide abundant access to food and low energy expenditure. Epigenetic research in experimental animals and retrospective research in humans confirm that environmental influences during developmental period have profound consequences on the phenotypic expression of biological and behavioral traits during adulthood. Research on epigenetics is a productive direction for human biologists concerned with understanding the origins of human biological variability. Am. J. Hum. Biol., 2009. © 2009 Wiley-Liss, Inc. [source] Influence of nitric oxide synthase inhibition on pulmonary O2 uptake kinetics during supra-maximal exercise in humansTHE JOURNAL OF PHYSIOLOGY, Issue 2 2004Daryl P. Wilkerson We have recently reported that inhibition of nitric oxide synthase (NOS) with NG -nitro- l -arginine methyl ester (l -NAME) accelerates the ,phase II' pulmonary O2 uptake kinetics following the onset of moderate and heavy intensity submaximal exercise in humans. These data suggest that the influence of nitric oxide (NO) on mitochondrial function is an important factor in the inertia to aerobic respiration that is evident in the transition from a lower to a higher metabolic rate. The purpose of the present study was to investigate the influence of l -NAME on pulmonary kinetics following the onset of supra-maximal exercise, where it has been suggested that O2 availability represents an additional limitation to kinetics. Seven healthy young men volunteered to participate in this study. Following an incremental cycle ergometer test for the determination of , the subjects returned on two occasions to perform a ,step' exercise test from a baseline of unloaded cycling to a work rate calculated to require 105%, preceded either by systemic infusion of l -NAME (4 mg kg,1 in 50 ml saline) or 50 ml saline as a control (Con). Pulmonary gas exchange was measured on a breath-by-breath basis throughout the exercise tests. The duration of ,phase I' was greater with l -NAME (Con: 14.0 ± 2.1 versusl -NAME: 16.0 ± 1.6 s; P= 0.03), suggestive of a slower cardiovascular adaptation following the onset of exercise. However, the phase II time constant was reduced by 44% with l -NAME (Con: 36.3 ± 17.3 versusl -NAME: 20.4 ± 8.3 s; P= 0.01). The accumulation of blood lactate during exercise was also reduced with l -NAME (Con: 4.0 ± 1.1 versusl -NAME: 2.7 ± 2.1 mm; P= 0.04). These data indicate that skeletal muscle NO production represents an important limitation to the acceleration of oxidative metabolism following the onset of supra-maximal exercise in humans. [source] Central and peripheral cardiovascular adaptations to exercise in endurance-trained childrenACTA PHYSIOLOGICA, Issue 2 2002S. NOTTIN ABSTRACT Stroke volume (SV) response to exercise depends on changes in cardiac filling, intrinsic myocardial contractility and left ventricular afterload. The aim of the present study was to identify whether these variables are influenced by endurance training in pre-pubertal children during a maximal cycle test. SV, cardiac output (Doppler echocardiography), left ventricular dimensions (time,movement echocardiography) as well as arterial pressure and systemic vascular resistances were assessed in 10 child cyclists (VO2max: 58.5 ± 4.4 mL min,1 kg,1) and 13 untrained children (UTC) (VO2max: 45.9 ± 6.7 mL min,1 kg,1). All variables were measured at the end of the resting period, during the final minute of each workload and during the last minute of the progressive maximal aerobic test. At rest and during exercise, stroke index was significantly higher in the child cyclists than in UTC. However, the SV patterns were strictly similar for both groups. Moreover, the patterns of diastolic and systolic left ventricular dimensions, and the pattern of systemic vascular resistance of the child cyclists mimicked those of the UTC. SV patterns, as well as their underlying mechanisms, were not altered by endurance training in children. This result implied that the higher maximal SV obtained in child cyclists depended on factors influencing resting SV, such as cardiac hypertrophy, augmented myocardium relaxation properties or expanded blood volume. [source] Exercise-induced neuronal plasticity in central autonomic networks: role in cardiovascular controlEXPERIMENTAL PHYSIOLOGY, Issue 9 2009Lisete C. Michelini It is now well established that brain plasticity is an inherent property not only of the developing but also of the adult brain. Numerous beneficial effects of exercise, including improved memory, cognitive function and neuroprotection, have been shown to involve an important neuroplastic component. However, whether major adaptive cardiovascular adjustments during exercise, needed to ensure proper blood perfusion of peripheral tissues, also require brain neuroplasticity, is presently unknown. This review will critically evaluate current knowledge on proposed mechanisms that are likely to underlie the continuous resetting of baroreflex control of heart rate during/after exercise and following exercise training. Accumulating evidence indicates that not only somatosensory afferents (conveyed by skeletal muscle receptors, baroreceptors and/or cardiopulmonary receptors) but also projections arising from central command neurons (in particular, peptidergic hypothalamic pre-autonomic neurons) converge into the nucleus tractus solitarii (NTS) in the dorsal brainstem, to co-ordinate complex cardiovascular adaptations during dynamic exercise. This review focuses in particular on a reciprocally interconnected network between the NTS and the hypothalamic paraventricular nucleus (PVN), which is proposed to act as a pivotal anatomical and functional substrate underlying integrative feedforward and feedback cardiovascular adjustments during exercise. Recent findings supporting neuroplastic adaptive changes within the NTS,PVN reciprocal network (e.g. remodelling of afferent inputs, structural and functional neuronal plasticity and changes in neurotransmitter content) will be discussed within the context of their role as important underlying cellular mechanisms supporting the tonic activation and improved efficacy of these central pathways in response to circulatory demand at rest and during exercise, both in sedentary and in trained individuals. We hope this review will stimulate more comprehensive studies aimed at understanding cellular and molecular mechanisms within CNS neuronal networks that contribute to exercise-induced neuroplasticity and cardiovascular adjustments. [source] REVIEW ARTICLE: Uterine NK Cells, Spiral Artery Modification and the Regulation of Blood Pressure During Mouse PregnancyAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2010Suzanne D. Burke Citation Burke SD, Barrette VF, Gravel J, Carter ALI, Hatta K, Zhang J, Chen Z, Leno-Durán E, Bianco J, Leonard S, Murrant C, Adams MA, Anne Croy B. Uterine NK cells, spiral artery modification and the regulation of blood pressure during mouse pregnancy. Am J Reprod Immunol 2010 Reproductive success in mammals involves coordinated changes in the immune and cardiovascular as well as in the neuroendocrine and reproductive systems. This review addresses studies that identify potential links for NK cells and T cells with the local and systemic cardiovascular adaptations of pregnancy. The studies reviewed have utilized immunohistochemisty and in vivo analyses of vascular parameters by ultrasound, chronic monitoring of hemodynamics via radiotelemetric recording and intravital microscopy. At the uterine level, functional subsets of uterine natural killer cells were identified. These included subsets expressing molecules important for vasoregulation, in addition to those previously identified for angiogenesis. Spiral arteries showed conducted responses that could account for conceptus control of vasoactivity and mouse gestational blood pressure 5-phase pattern. Vascular immunology is an emerging transdisciplinary field, critical for both reproductive immunology and cardiovascular disease. [source] | |||||||||||||