AJP: Regulatory, Integrative and Comparative Physiology This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Metabolic effects of prazosin on skeletal muscle insulin resistance in glucocorticoid-treated male rats
High-dose glucocorticoids (GC) induce skeletal muscle atrophy, insulin resistance, and reduced muscle capillarization. Identification of treatments to prevent or reverse capillary rarefaction and metabolic deterioration caused by prolonged elevations in GCs would be therapeutically beneficial. Chronic administration of prazosin, an α1-adrenergic antagonist, increases skeletal muscle capillarization in healthy rodents and, recently, in a rodent model of elevated GCs and hyperglycemia. The purpose of this study was to determine whether prazosin administration would improve glucose tolerance and insulin sensitivity, thr...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 31, 2016 Category: Physiology Authors: Dunford, E. C., Mandel, E. R., Mohajeri, S., Haas, T. L., Riddell, M. C. Tags: Research Article Source Type: research

Reduced compensatory responses to maintain central blood volume during hypovolemic stress in women with vasovagal syncope
In conclusion, in VVS women, mobilization of peripheral venous blood and net fluid absorption from tissue to blood during hypovolemic stress were decreased partly as a result of an attenuated vasoconstrictor response. This may seriously impede maintenance of cardiac output during hypovolemic stress and could contribute to the pathogenesis of VVS. (Source: AJP: Regulatory, Integrative and Comparative Physiology)
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 31, 2016 Category: Physiology Authors: Skoog, J., Zachrisson, H., Länne, T., Lindenberger, M. Tags: Research Article Source Type: research

Sympathetic responsiveness is not increased in women with a history of hypertensive pregnancy
Hypertensive pregnancy (HTNP) is a risk factor for future cardiovascular disease. Exaggerated cardiovascular responses to physical stress are also considered an independent marker of cardiovascular disease risk. However, there are limited data regarding the blood pressure (BP) responses to acute stress in women, who have a history of HTNP. Hence, the aim of the study is to compare BP responses to a physical stress in postmenopausal women with a history of HTNP to age- and parity-matched women with a history of normotensive pregnancy (NP). Beat-to-beat BP and heart rate was recorded in 64 postmenopausal women with [age = 58...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 31, 2016 Category: Physiology Authors: Ranadive, S. M., Harvey, R. E., Lahr, B. D., Miller, V. M., Joyner, M. J., Barnes, J. N. Tags: Research Article Source Type: research

The protective effect of apolipoprotein in models of trophoblast invasion and preeclampsia
This study investigated whether apoA-I protects against hypertension and adverse placental changes in a proinflammatory cytokine (TNF-α)-induced model of preeclampsia. Further, this study investigated whether apoA-I protects against the inhibitory effect of TNF-α in a human in vitro model of trophoblast invasion. Administration of apoA-I to pregnant mice before infusion with TNF-α resulted in a significant reduction in the cytokine-induced increase in systolic blood pressure. MRI measurement of T2 relaxation, a parameter that is tissue specific and sensitive to physiological changes within tissues, showed...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 31, 2016 Category: Physiology Authors: Charlton, F., Bobek, G., Stait-Gardner, T., Price, W. S., Mirabito Colafella, K. M., Xu, B., Makris, A., Rye, K.-A., Hennessy, A. Tags: Research Article Source Type: research

Cardiac remodeling and increased central venous pressure underlie elevated stroke volume and cardiac output of seawater-acclimated rainbow trout
Substantial increases in cardiac output (CO), stroke volume (SV), and gastrointestinal blood flow are essential for euryhaline rainbow trout (Oncorhyncus mykiss) osmoregulation in seawater. However, the underlying hemodynamic mechanisms responsible for these changes are unknown. By examining a range of circulatory and cardiac morphological variables of seawater- and freshwater-acclimated rainbow trout, the present study revealed a significantly higher central venous pressure (CVP) in seawater-acclimated trout (~0.09 vs. –0.02 kPa). This serves to increase cardiac end-diastolic volume in seawater and explains the elev...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 31, 2016 Category: Physiology Authors: Brijs, J., Sandblom, E., Dekens, E., Näslund, J., Ekström, A., Axelsson, M. Tags: Research Article Source Type: research

Intradermal administration of endothelin-1 attenuates endothelium-dependent and -independent cutaneous vasodilation via Rho kinase in young adults
We recently showed that intradermal administration of endothelin-1 diminished endothelium-dependent and -independent cutaneous vasodilation. We evaluated the hypothesis that Rho kinase may be a mediator of this response. We also sought to evaluate if endothelin-1 increases sweating. In 12 adults (25 ± 6 yr), we measured cutaneous vascular conductance (CVC) and sweating during 1) endothelium-dependent vasodilation induced via administration of incremental doses of methacholine (0.25, 5, 100, and 2,000 mM each for 25 min) and 2) endothelium-independent vasodilation induced via administration of 50 mM sodium nitropruss...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 31, 2016 Category: Physiology Authors: Fujii, N., Amano, T., Halili, L., Louie, J. C., Zhang, S. Y., McNeely, B. D., Kenny, G. P. Tags: Research Article Source Type: research

Dietary nitrate supplementation and exercise tolerance in patients with heart failure with reduced ejection fraction
Endothelial dysfunction and reduced nitric oxide (NO) signaling are key abnormalities leading to skeletal muscle oxygen delivery-utilization mismatch and poor physical capacity in patients with heart failure with reduced ejection fraction (HFrEF). Oral inorganic nitrate supplementation provides an exogenous source of NO that may enhance locomotor muscle function and oxygenation with consequent improvement in exercise tolerance in HFrEF. Thirteen patients (left ventricular ejection fraction ≤40%) were enrolled in a double-blind, randomized crossover study to receive concentrated nitrate-rich (nitrate) or nitrate-depleted...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 31, 2016 Category: Physiology Authors: Hirai, D. M., Zelt, J. T., Jones, J. H., Castanhas, L. G., Bentley, R. F., Earle, W., Staples, P., Tschakovsky, M. E., McCans, J., ODonnell, D. E., Neder, J. A. Tags: Research Article Source Type: research

Metabolic abnormalities and obesitys impact on the risk for developing preeclampsia
Preeclampsia (PE), a hypertensive disorder of pregnancy, is increasing as a major contributor to perinatal and long-term morbidity of mother and offspring. PE is thought to originate from ischemic insults in the placenta driving the release of prohypertensive anti-angiogenic [soluble fms-like tyrosine kinase-1 (sFlt-1)] and proinflammatory [tumor necrosis factor-α (TNF-α)] factors into the maternal circulation. Whereas the increased incidence of PE is hypothesized to be largely due to the obesity pandemic, the mechanisms whereby obesity increases this risk are unknown. The maternal endothelium is targeted by pl...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 31, 2016 Category: Physiology Authors: Spradley, F. T. Tags: Review Source Type: research

Do high-salt microenvironments drive hypertensive inflammation?
Hypertension is a global epidemic affecting over one billion people worldwide. Despite this, the etiology of most cases of human hypertension remains obscure, and treatment remains suboptimal. Excessive dietary salt and inflammation are known contributors to the pathogenesis of this disease. Recently, it has been recognized that salt can accumulate in the skin and skeletal muscle, producing concentrations of sodium greater than the plasma in hypertensive animals and humans. Such elevated levels of sodium have been shown to alter immune cell function. Here, we propose a model in which tissue salt accumulation causes an immu...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 31, 2016 Category: Physiology Authors: Foss, J. D., Kirabo, A., Harrison, D. G. Tags: Review Source Type: research

Neurovascular control of blood pressure is influenced by aging, sex, and sex hormones
In this review, we highlight that the relationship between muscle sympathetic nerve activity (MSNA) and mean arterial pressure is complex, differs by sex, and changes with age. In young men there is an inverse relationship between MSNA and cardiac output where high MSNA is compensated for by low cardiac output. This inverse relationship is not seen in older men. In young women sympathetic vasoconstriction is offset by β-adrenoreceptor mediated vasodilation, limiting the ability of young women to maintain blood pressure in response to orthostatic stress. However, β-mediated dilation in women is attenuated with age...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 21, 2016 Category: Physiology Authors: Baker, S. E., Limberg, J. K., Ranadive, S. M., Joyner, M. J. Tags: Call for Papers Source Type: research

Role of endogenous carbon monoxide in the control of breathing in zebrafish (Danio rerio)
This study demonstrates for the first time that CO plays an inhibitory role in the control of breathing in larval and adult zebrafish. (Source: AJP: Regulatory, Integrative and Comparative Physiology)
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 21, 2016 Category: Physiology Authors: Tzaneva, V., Perry, S. F. Tags: Respiration Source Type: research

Coupling between arterial and venous cerebral blood flow during postural change
In supine humans the main drainage from the brain is through the internal jugular vein (IJV), but the vertebral veins (VV) become important during orthostatic stress because the IJV is partially collapsed. To identify the effect of this shift in venous drainage from the brain on the cerebral circulation, this study addressed both arterial and venous flow responses in the "anterior" and "posterior" parts of the brain when nine healthy subjects (5 men) were seated and flow was manipulated by hyperventilation and inhalation of 6% carbon dioxide (CO2). From a supine to a seated position, both internal carotid artery (ICA) and ...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 21, 2016 Category: Physiology Authors: Ogoh, S., Washio, T., Sasaki, H., Petersen, L. G., Secher, N. H., Sato, K. Tags: Cardiovascular and renal integration Source Type: research

Day-night dependence of gene expression and inflammatory responses in the remodeling murine heart post-myocardial infarction
This study was designed to test whether time of day of MI triggers different gene expression, humoral, and innate inflammatory responses that contribute to cardiac repair after MI. Mice were infarcted by left anterior descending coronary artery ligation (MI model) within a 2-h time window either shortly after lights on or lights off, and the early remodeling responses at 8 h postinfarction were examined. We found that sleep-MI preferentially triggers early expression of genes associated with inflammatory responses, whereas wake-MI triggers more genes associated with metabolic pathways and transcription/translation, by micr...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 21, 2016 Category: Physiology Authors: Bennardo, M., Alibhai, F., Tsimakouridze, E., Chinnappareddy, N., Podobed, P., Reitz, C., Pyle, W. G., Simpson, J., Martino, T. A. Tags: Cardiovascular and renal integration Source Type: research

Dietary {alpha}-linolenic acid supplementation alters skeletal muscle plasma membrane lipid composition, sarcolemmal FAT/CD36 abundance, and palmitate transport rates
The cellular processes influenced by consuming polyunsaturated fatty acids remains poorly defined. Within skeletal muscle, a rate-limiting step in fatty acid oxidation is the movement of lipids across the sarcolemmal membrane, and therefore, we aimed to determine the effects of consuming flaxseed oil high in α-linolenic acid (ALA), on plasma membrane lipid composition and the capacity to transport palmitate. Rats fed a diet supplemented with ALA (10%) displayed marked increases in omega-3 polyunsaturated fatty acids (PUFAs) within whole muscle and sarcolemmal membranes (approximately five-fold), at the apparent expen...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 21, 2016 Category: Physiology Authors: Chorner, Z., Barbeau, P.-A., Castellani, L., Wright, D. C., Chabowski, A., Holloway, G. P. Tags: Obesity, diabetes and energy homeostasis Source Type: research

High-fat diet-induced glucose dysregulation is independent of changes in islet ACE2 in mice
While restoration of ACE2 activity in the pancreas leads to improvement of glycemia in experimental models of Type 2 diabetes, global deficiency in ACE2 disrupts β-cell function and impairs glucose tolerance in mice, demonstrating the physiological role of ACE2 in glucose homeostasis. Although the contribution of pancreatic ACE2 to glucose regulation has been demonstrated in genetic models of diabetes and in models with overexpression of the renin-angiotensin system (RAS), it is unclear whether islet ACE2 is involved in glycemic control in common models of human Type 2 diabetes. To determine whether diet-induced diabe...
Source: AJP: Regulatory, Integrative and Comparative Physiology - December 21, 2016 Category: Physiology Authors: Chodavarapu, H., Chhabra, K. H., Xia, H., Shenoy, V., Yue, X., Lazartigues, E. Tags: Obesity, diabetes and energy homeostasis Source Type: research