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.

Bladder urine oxygen tension for assessing renal medullary oxygenation in rabbits: experimental and modeling studies
Oxygen tension (Po2) of urine in the bladder could be used to monitor risk of acute kidney injury if it varies with medullary Po2. Therefore, we examined this relationship and characterized oxygen diffusion across walls of the ureter and bladder in anesthetized rabbits. A computational model was then developed to predict medullary Po2 from bladder urine Po2. Both intravenous infusion of [Phe2,Ile3,Orn8]-vasopressin and infusion of NG-nitro-l-arginine reduced urinary Po2 and medullary Po2 (8–17%), yet had opposite effects on renal blood flow and urine flow. Changes in bladder urine Po2 during these stimuli correlated ...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 31, 2016 Category: Physiology Authors: Sgouralis, I., Kett, M. M., Ow, C. P. C., Abdelkader, A., Layton, A. T., Gardiner, B. S., Smith, D. W., Lankadeva, Y. R., Evans, R. G. Tags: Fluid and Electrolyte Homeostasis Source Type: research

Aortic pulse pressure homeostasis emerges from physiological adaptation of systemic arteries to local mechanical stresses
Aortic pulse pressure arises from the interaction of the heart, the systemic arterial system, and peripheral microcirculations. The complex interaction between hemodynamics and arterial remodeling precludes the ability to experimentally ascribe changes in aortic pulse pressure to particular adaptive responses. Therefore, the purpose of the present work was to use a human systemic arterial system model to test the hypothesis that pulse pressure homeostasis can emerge from physiological adaptation of systemic arteries to local mechanical stresses. First, we assumed a systemic arterial system that had a realistic topology con...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 31, 2016 Category: Physiology Authors: Nguyen, P. H., Tuzun, E., Quick, C. M. Tags: Cardiovascular and Renal Integration Source Type: research

Restoring placental growth factor-soluble fms-like tyrosine kinase-1 balance reverses vascular hyper-reactivity and hypertension in pregnancy
Preeclampsia (PE) is a pregnancy-related hypertensive disorder (HTN-Preg) with unclear mechanism. An imbalance between antiangiogenic soluble fms-like tyrosine kinase-1 (sFlt-1) and angiogenic placental growth factor (PlGF) has been observed in PE, but the vascular targets and signaling pathways involved are unclear. We assessed the extent of sFlt-1/PlGF imbalance and vascular dysfunction in a rat model of HTN-Preg produced by reduction of uteroplacental perfusion pressure (RUPP), and tested whether inducing a comparable sFlt-1/PlGF imbalance by infusing sFlt-1 (10 μg·kg–1·day–1) in day 14 preg...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 31, 2016 Category: Physiology Authors: Zhu, M., Ren, Z., Possomato-Vieira, J. S., Khalil, R. A. Tags: Hormones, Reproduction and Development Source Type: research

Oxidized fish oil in rat pregnancy causes high newborn mortality and increases maternal insulin resistance
Fish oil is commonly taken by pregnant women, and supplements sold at retail are often oxidized. Using a rat model, we aimed to assess the effects of supplementation with oxidized fish oil during pregnancy in mothers and offspring, focusing on newborn viability and maternal insulin sensitivity. Female rats were allocated to a control or high-fat diet and then mated. These rats were subsequently randomized to receive a daily gavage treatment of 1 ml of unoxidized fish oil, a highly oxidized fish oil, or control (water) throughout pregnancy. At birth, the gavage treatment was stopped, but the same maternal diets were fed ad ...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 31, 2016 Category: Physiology Authors: Albert, B. B., Vickers, M. H., Gray, C., Reynolds, C. M., Segovia, S. A., Derraik, J. G. B., Lewandowski, P. A., Garg, M. L., Cameron-Smith, D., Hofman, P. L., Cutfield, W. S. Tags: Obesity, Diabetes and Energy Homeostasis Source Type: research

Hypothalamic action of phoenixin to control reproductive hormone secretion in females: importance of the orphan G protein-coupled receptor Gpr173
Sexual maturation and maintenance of reproductive function are regulated by neurohormonal communication between the hypothalamus, pituitary, and gonads (referred to as the HPG axis). Phoenixin (PNX) is a newly identified, endogenous peptide abundantly produced in the hypothalamus and shown to be an important mediator of ovarian cyclicity. However, the underlying mechanisms by which phoenixin functions within the HPG axis are unknown. Previous in vitro studies demonstrated a direct action of PNX on gonadotrophs to potentiate gonadotrophin-releasing hormone (GnRH) induced luteinizing hormone (LH) secretion. Therefore, we hyp...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 31, 2016 Category: Physiology Authors: Stein, L. M., Tullock, C. W., Mathews, S. K., Garcia-Galiano, D., Elias, C. F., Samson, W. K., Yosten, G. L. C. Tags: Hormones, Reproduction and Development Source Type: research

Regulation of fetal liver growth in a model of diet restriction in the pregnant rat
Limited nutrient availability is a cause of intrauterine growth restriction (IUGR), a condition that has important implications for the well being of the offspring. Using the established IUGR model of maternal fasting in the rat, we investigated mechanisms that control gene expression and mRNA translation in late-gestation fetal liver. Maternal fasting for 48 h during the last one-third of gestation was associated with a 10–15% reduction in fetal body weight and a disproportionate one-third reduction in total fetal liver protein. The fetal liver transcriptome showed only subtle changes consistent with reduced cell pr...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 31, 2016 Category: Physiology Authors: Boylan, J. M., Sanders, J. A., Gruppuso, P. A. Tags: Obesity, Diabetes and Energy Homeostasis Source Type: research

Linagliptin treatment improves cerebrovascular function and remodeling and restores reduced cerebral perfusion in Type 2 diabetes
In this study, we hypothesized that DPP-IV inhibition with linagliptin would improve impaired cerebral perfusion in diabetic rats, as well as improve insulin-induced cerebrovascular relaxation and reverse pathological cerebrovascular remodeling. We further postulated that these changes would lead to a subsequent improvement of cognitive function. Male Type-2 diabetic and nondiabetic Goto-Kakizaki rats were treated with linagliptin for 4 wk, and blood glucose and DPP-IV plasma levels were assessed. Cerebral perfusion was assessed after treatment using laser-Doppler imaging, and dose response to insulin (10–13 M–...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 31, 2016 Category: Physiology Authors: Hardigan, T., Yasir, A., Abdelsaid, M., Coucha, M., El-Shaffey, S., Li, W., Johnson, M. H., Ergul, A. Tags: Obesity, Diabetes and Energy Homeostasis Source Type: research

Thermal conditions experienced during differentiation affect metabolic and contractile phenotypes of mouse myotubes
Central pathways regulate metabolic responses to cold in endotherms to maintain relatively stable internal core body temperatures. However, peripheral muscles routinely experience temperatures lower than core body temperature, so that it would be advantageous for peripheral tissues to respond to temperature changes independently from core body temperature regulation. Early developmental conditions can influence offspring phenotypes, and here we tested whether developing muscle can compensate locally for the effects of cold exposure independently from central regulation. Muscle myotubes originate from undifferentiated myobl...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 31, 2016 Category: Physiology Authors: Little, A. G., Seebacher, F. Tags: Respiration Source Type: research

Hypernatremia-induced vasopressin secretion is not altered in TRPV1-/- rats
Changes in osmolality or extracellular NaCl concentrations are detected by specialized neurons in the hypothalamus to increase vasopressin (VP) and stimulate thirst. Recent in vitro evidence suggests this process is mediated by an NH2-terminal variant of the transient receptor potential vanilloid type 1 (TRPV1) channel expressed by osmosensitive neurons of the lamina terminalis and vasopressinergic neurons of the supraoptic nucleus. The present study tested this hypothesis in vivo by analysis of plasma VP levels during acute hypernatremia in awake control and TRPV1–/– rats. TRPV1–/– rats were produc...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 31, 2016 Category: Physiology Authors: Tucker, A. B., Stocker, S. D. Tags: Neural Control Source Type: research

Cardiac oxygen limitation during an acute thermal challenge in the European perch: effects of chronic environmental warming and experimental hyperoxia
Oxygen supply to the heart has been hypothesized to limit cardiac performance and whole animal acute thermal tolerance (CTmax) in fish. We tested these hypotheses by continuously measuring venous oxygen tension (Pvo2) and cardiovascular variables in vivo during acute warming in European perch (Perca fluviatilis) from a reference area during summer (18°C) and a chronically heated area (Biotest enclosure) that receives warm effluent water from a nuclear power plant and is normally 5–10°C above ambient (24°C at the time of experiments). While CTmax was 2.2°C higher in Biotest compared with reference perc...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 11, 2016 Category: Physiology Authors: Ekström, A., Brijs, J., Clark, T. D., Gräns, A., Jutfelt, F., Sandblom, E. Tags: Cardiovascular and Renal Integration Source Type: research

Chronic intermittent hypoxia accelerates coronary microcirculatory dysfunction in insulin-resistant Goto-Kakizaki rats
Chronic intermittent hypoxia (IH) induces oxidative stress and inflammation, which impair vascular endothelial function. Long-term insulin resistance also leads to endothelial dysfunction. We determined, in vivo, whether the effects of chronic IH and insulin resistance on endothelial function augment each other. Male 12-wk-old Goto-Kakizaki (GK) and Wistar control rats were subjected to normoxia or chronic IH (90-s N2, 5% O2 at nadir, 90-s air, 20 cycles/h, 8 h/day) for 4 wk. Coronary endothelial function was assessed using microangiography with synchrotron radiation. Imaging was performed at baseline, during infusion of a...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 11, 2016 Category: Physiology Authors: Chen, Y. C., Inagaki, T., Fujii, Y., Schwenke, D. O., Tsuchimochi, H., Edgley, A. J., Umetani, K., Zhang, Y., Kelly, D. J., Yoshimoto, M., Nagai, H., Evans, R. G., Kuwahira, I., Shirai, M., Pearson, J. T. Tags: Obesity, Diabetes and Energy Homeostasis Source Type: research

elPBN neurons regulate rVLM activity through elPBN-rVLM projections during activation of cardiac sympathetic afferent nerves
The external lateral parabrachial nucleus (elPBN) within the pons and rostral ventrolateral medulla (rVLM) contributes to central processing of excitatory cardiovascular reflexes during stimulation of cardiac sympathetic afferent nerves (CSAN). However, the importance of elPBN cardiovascular neurons in regulation of rVLM activity during CSAN activation remains unclear. We hypothesized that CSAN stimulation excites the elPBN cardiovascular neurons and, in turn, increases rVLM activity through elPBN-rVLM projections. Compared with controls, in rats subjected to microinjection of retrograde tracer into the rVLM, the numbers o...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 11, 2016 Category: Physiology Authors: Guo, Z.-L., Longhurst, J. C., Tjen-A-Looi, S. C., Fu, L.-W. Tags: Neural Control Source Type: research

Diurnal variation in the control of ventilation in response to rising body temperature during exercise in the heat
We investigated whether heat-induced hyperventilation during exercise is affected by time of day, as diurnal variation leads to higher core temperatures in the evening. Nineteen male subjects were divided into two experiments (protocol 1, n = 10 and protocol 2, n = 9). In protocol 1, subjects performed cycle exercise at 50% peak oxygen uptake in the heat (37°C and 50% RH) in the morning (0600) and evening (1800). Results showed that baseline resting and exercising esophageal temperature (Tes) were significantly (0.5°C) higher in the evening than morning. Minute ventilation (Ve) increased from 54.3 ± 7.9 and ...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 11, 2016 Category: Physiology Authors: Tsuji, B., Honda, Y., Kondo, N., Nishiyasu, T. Tags: Respiration Source Type: research

Thermotherapy reduces blood pressure and circulating endothelin-1 concentration and enhances leg blood flow in patients with symptomatic peripheral artery disease
Leg thermotherapy (TT) application reduces blood pressure (BP) and increases both limb blood flow and circulating levels of anti-inflammatory mediators in healthy, young humans and animals. The purpose of the present study was to determine the impact of TT application using a water-circulating garment on leg and systemic hemodynamics and on the concentrations of circulating cytokines and vasoactive mediators in patients with symptomatic peripheral artery disease (PAD). Sixteen patients with PAD and intermittent claudication (age: 63 ± 9 yr) completed three experimental sessions in a randomized order: TT, control int...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 11, 2016 Category: Physiology Authors: Neff, D., Kuhlenhoelter, A. M., Lin, C., Wong, B. J., Motaganahalli, R. L., Roseguini, B. T. Tags: Translational Physiology Source Type: research

Heat therapy promotes the expression of angiogenic regulators in human skeletal muscle
Heat therapy has been shown to promote capillary growth in skeletal muscle and in the heart in several animal models, but the effects of this therapy on angiogenic signaling in humans are unknown. We evaluated the acute effect of lower body heating (LBH) and unilateral thigh heating (TH) on the expression of angiogenic regulators and heat shock proteins (HSPs) in healthy young individuals. Exposure to LBH (n = 18) increased core temperature (Tc) from 36.9 ± 0.1 to 37.4 ± 0.1°C (P < 0.01) and average leg skin temperature (Tleg) from 33.1 ± 0.1 to 39.6 ± 0.1°C (P < 0.01), but did not...
Source: AJP: Regulatory, Integrative and Comparative Physiology - August 11, 2016 Category: Physiology Authors: Kuhlenhoelter, A. M., Kim, K., Neff, D., Nie, Y., Blaize, A. N., Wong, B. J., Kuang, S., Stout, J., Song, Q., Gavin, T. P., Roseguini, B. T. Tags: Translational Physiology Source Type: research