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.

Glycinergic inhibition of BAT sympathetic premotor neurons in rostral raphe pallidus
The rostral raphe pallidus (rRPa) contains sympathetic premotor neurons controlling thermogenesis in brown adipose tissue (BAT). We sought to determine whether a tonic activation of glycineA receptors (GlyAR) in the rRPa contributes to the inhibitory regulation of BAT sympathetic nerve activity (SNA) and of cardiovascular parameters in anesthetized rats. Nanoinjection of the GlyAR antagonist, strychnine (STR), into the rRPa of intact rats increased BAT SNA (peak: +495%), BAT temperature (TBAT, +1.1°C), expired CO2, (+0.4%), core body temperature (TCORE, +0.2°C), mean arterial pressure (MAP, +4 mmHg), and heart rate...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 1, 2017 Category: Physiology Authors: Conceicao, E. P. S. d., Madden, C. J., Morrison, S. F. Tags: Research Article Source Type: research

Expression of leptin receptor in the oviduct of Chinese brown frog (Rana dybowskii)
In this study, we investigated the expression of leptin receptor (Ob-Rb) in Rana dybowskii oviduct during the breeding period and prehibernation. Histologically, the oviduct of Rana dybowskii consists of glandular cells, tubule lumen, and epithelial cells. The oviductal weight and pipe diameter also revealed significant differences, which were higher in prehibernation than that of the breeding period. Ob-Rb was observed in stromal cells of oviductal tissue in both the breeding period and prehibernation. The mean protein and mRNA levels of the Ob-Rb were significantly higher in prehibernation as compared with the breeding p...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 1, 2017 Category: Physiology Authors: Xi, L., Liu, Y., Tang, Z., Sheng, X., Zhang, H., Weng, Q., Xu, M. Tags: Research Article Source Type: research

Greater sympathoadrenal activation with longer preventilation intervals after immediate cord clamping increases hemodynamic lability at birth in preterm lambs
This study tested the hypothesis that varying degrees of hemodynamic fluctuations seen after birth following immediate cord clamping were related to development of asphyxia with longer cord clamp-to-ventilation intervals, resulting in higher perinatal circulating levels of the catecholamines norepinephrine (NE) and epinephrine (Epi), and thus increased heart rate, blood pressures, and cardiac contractility after birth. Anesthetized preterm fetal lambs were instrumented with 1) aortic (AoT) and pulmonary trunk (PT) micromanometers to obtain pressures and the maximal rate of pressure rise (dP/dtmax) as a surrogate measure of...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 1, 2017 Category: Physiology Authors: Smolich, J. J., Kenna, K. R., Esler, M. D., Phillips, S. E., Lambert, G. W. Tags: Research Article Source Type: research

Erythropoiesis with endurance training: dynamics and mechanisms
In conclusion, ET leads to mild, transient increases in circulating EPO concentration, concurring with early PV expansion and lowered hematocrit, preceding gradual RBCV enhancement. (Source: AJP: Regulatory, Integrative and Comparative Physiology)
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 1, 2017 Category: Physiology Authors: Montero, D., Breenfeldt-Andersen, A., Oberholzer, L., Haider, T., Goetze, J. P., Meinild-Lundby, A.-K., Lundby, C. Tags: Research Article Source Type: research

Activation of CB1 receptors by 2-arachidonoylglycerol attenuates vasoconstriction induced by U46619 and angiotensin II in human and rat pulmonary arteries
Recent evidence suggests that endocannabinoids acting via cannabinoid CB1 receptors may modulate vascular responses of various vasoconstrictors in the rodent systemic vasculature. The aim of the study was to investigate whether endocannabinoids modulate the contractile responses evoked by a thromboxane A2 analog (U46619), angiotensin II (ANG II), serotonin (5-HT), and phenylephrine, which stimulate distinct Gq/11 protein-coupled receptors (thromboxane, ANG II type 1, 5-HT2, and α1-adrenergic receptors) in isolated endothelium-intact human and rat pulmonary arteries (hPAs and rPAs, respectively). The CB1 receptor anta...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 1, 2017 Category: Physiology Authors: Karpinska, O., Baranowska-Kuczko, M., Kloza, M., Ambrozewicz, E., Kozłowski, T., Kasacka, I., Malinowska, B., Kozłowska, H. Tags: Research Article Source Type: research

Muscle sympathetic nerve activity response to heat stress is attenuated in chronic heart failure patients
Heat stress evokes significant increases in muscle sympathetic nerve activity (MSNA) in healthy individuals. The MSNA response to heat stress in chronic heart failure (CHF) is unknown. We hypothesized that the MSNA response to heat stress is attenuated in CHF. Passive whole body heating was applied with water-perfused suits in 13 patients (61 ± 2 yr) with stable class II-III CHF, 12 age-matched (62 ± 2 yr) healthy subjects, and 14 young (24 ± 1 yr) healthy subjects. Mild heating (i.e., increases in skin temperature Tsk ~2–4°C, internal temperature Tcore <0.3°C) significantly decreased ...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 1, 2017 Category: Physiology Authors: Cui, J., Boehmer, J., Blaha, C., Sinoway, L. I. Tags: Research Article Source Type: research

Neurogenic hypertension and the secrets of respiration
Despite recent advances in the knowledge of the neural control of cardiovascular function, the cause of sympathetic overactivity in neurogenic hypertension remains unknown. Studies from our laboratory point out that rats submitted to chronic intermittent hypoxia (CIH), an experimental model of neurogenic hypertension, present changes in the central respiratory network that impact the pattern of sympathetic discharge and the levels of arterial pressure. In addition to the fine coordination of respiratory muscle contraction and relaxation, which is essential for O2 and CO2 pulmonary exchanges, neurons of the respiratory netw...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 1, 2017 Category: Physiology Authors: Machado, B. H., Zoccal, D. B., Moraes, D. J. A. Tags: Review Source Type: research

Abnormal cardiovascular response to exercise in hypertension: contribution of neural factors
During both dynamic (e.g., endurance) and static (e.g., strength) exercise there are exaggerated cardiovascular responses in hypertension. This includes greater increases in blood pressure, heart rate, and efferent sympathetic nerve activity than in normal controls. Two of the known neural factors that contribute to this abnormal cardiovascular response are the exercise pressor reflex (EPR) and functional sympatholysis. The EPR originates in contracting skeletal muscle and reflexly increases sympathetic efferent nerve activity to the heart and blood vessels as well as decreases parasympathetic efferent nerve activity to th...
Source: AJP: Regulatory, Integrative and Comparative Physiology - June 1, 2017 Category: Physiology Authors: Mitchell, J. H. Tags: Review Source Type: research

Sex-specific differences in age-dependent progression of aortic dysfunction and related cardiac remodeling in spontaneously hypertensive rats
This study documents sex-specific differences in the temporal progression of aortic dysfunction and LV hypertrophy in SHRs, which are independent of arterial pressure and are apparently mediated by higher AT2R expression in the heart and aorta of female SHRs. (Source: AJP: Regulatory, Integrative and Comparative Physiology)
Source: AJP: Regulatory, Integrative and Comparative Physiology - May 30, 2017 Category: Physiology Authors: Al-Gburi, S., Deussen, A. J., Galli, R., Muders, M. H., Zatschler, B., Neisser, A., Müller, B., Kopaliani, I. Tags: Research Article Source Type: research

Impact of lifelong exercise training on endothelial ischemia-reperfusion and ischemic preconditioning in humans
Reperfusion is essential for ischemic tissue survival, but causes additional damage to the endothelium [i.e., ischemia-reperfusion (I/R) injury]. Ischemic preconditioning (IPC) refers to short repetitive episodes of ischemia that can protect against I/R. However, IPC efficacy attenuates with older age. Whether physical inactivity contributes to the attenuated efficacy of IPC to protect against I/R injury in older humans is unclear. We tested the hypotheses that lifelong exercise training relates to 1) attenuated endothelial I/R and 2) maintained IPC efficacy that protects veteran athletes against endothelial I/R. In 18 sed...
Source: AJP: Regulatory, Integrative and Comparative Physiology - May 30, 2017 Category: Physiology Authors: Maessen, M. F. H., van Mil, A. C. C. M., Straathof, Y., Riksen, N. P., Rongen, G. A. P. J. M., Hopman, M. T. E., Eijsvogels, T. M. H., Thijssen, D. H. J. Tags: Research Article Source Type: research

The roles of KCa, KATP, and KV channels in regulating cutaneous vasodilation and sweating during exercise in the heat
We recently showed the varying roles of Ca2+-activated (KCa), ATP-sensitive (KATP), and voltage-gated (KV) K+ channels in regulating cholinergic cutaneous vasodilation and sweating in normothermic conditions. However, it is unclear whether the respective contributions of these K+ channels remain intact during dynamic exercise in the heat. Eleven young (23 ± 4 yr) men completed a 30-min exercise bout at a fixed rate of metabolic heat production (400 W) followed by a 40-min recovery period in the heat (35°C, 20% relative humidity). Cutaneous vascular conductance (CVC) and local sweat rate were assessed at four for...
Source: AJP: Regulatory, Integrative and Comparative Physiology - May 30, 2017 Category: Physiology Authors: Louie, J. C., Fujii, N., Meade, R. D., McNeely, B. D., Kenny, G. P. Tags: Research Article Source Type: research

Examination of carnitine palmitoyltransferase 1 abundance in white adipose tissue: implications in obesity research
Carnitine palmitoyltransferase 1 (CPT1) is essential for the transport of long-chain fatty acids into the mitochondria for oxidation. Recently, it was reported that decreased CPT1b mRNA in adipose tissue was a contributing factor for obesity in rats. We therefore closely examined the expression level of Cpt1 in adipose tissue from mice, rats, and humans. Cpt1a is the predominate isoform in adipose tissue from all three species. Rat white adipose tissue has a moderate amount of Cpt1b mRNA, but it is very minor compared with Cpt1b expression in muscle. Total CPT1 activity in adipose tissue is also minor relative to other tis...
Source: AJP: Regulatory, Integrative and Comparative Physiology - May 30, 2017 Category: Physiology Authors: Warfel, J. D., Vandanmagsar, B., Dubuisson, O. S., Hodgeson, S. M., Elks, C. M., Ravussin, E., Mynatt, R. L. Tags: Research Article Source Type: research

Reduced skeletal muscle fiber size following caloric restriction is associated with calpain-mediated proteolysis and attenuation of IGF-1 signaling
Caloric restriction decreases skeletal muscle mass in mammals, principally due to a reduction in fiber size. The effect of suboptimal nutrient intake on skeletal muscle metabolic properties in neonatal calves was examined. The longissimus muscle (LM) was collected after a control (CON) or caloric restricted (CR) diet was cosnumed for 8 wk and muscle fiber size, gene expression, and metabolic signal transduction activity were measured. Results revealed that CR animals had smaller (P < 0.05) LM fiber cross-sectional area than CON, as expected. Western blot analysis detected equivalent amounts of peroxisome proliferator-ac...
Source: AJP: Regulatory, Integrative and Comparative Physiology - May 30, 2017 Category: Physiology Authors: Lu, Y., Bradley, J. S., McCoski, S. R., Gonzalez, J. M., Ealy, A. D., Johnson, S. E. Tags: Research Article Source Type: research

Variable reliability of surrogate measures of insulin sensitivity after Roux-en-Y gastric bypass
In conclusion, surrogate measures of insulin sensitivity may not reflect results obtained with gold standard methodology after RYGB, underscoring the importance of critical reflection when surrogate endpoints are used. Fasting surrogate indices may be particularly affected by post-RYGB changes in insulin clearance, whereas the validity of OGTT-derived surrogates may be compromised by surgical rearrangements of the gut. (Source: AJP: Regulatory, Integrative and Comparative Physiology)
Source: AJP: Regulatory, Integrative and Comparative Physiology - May 30, 2017 Category: Physiology Authors: Bojsen-Moller, K. N., Dirksen, C., Svane, M. S., Jorgensen, N. B., Holst, J. J., Richter, E. A., Madsbad, S. Tags: Research Article Source Type: research

Aortic depressor nerve stimulation does not impede the dynamic characteristics of the carotid sinus baroreflex in normotensive or spontaneously hypertensive rats
Recent clinical trials in patients with drug-resistant hypertension indicate that electrical activation of the carotid sinus baroreflex can reduce arterial pressure (AP) for more than a year. To examine whether the electrical stimulation from one baroreflex system impedes normal short-term AP regulation via another unstimulated baroreflex system, we electrically stimulated the left aortic depressor nerve (ADN) while estimating the dynamic characteristics of the carotid sinus baroreflex in anesthetized normotensive Wistar-Kyoto (WKY; n = 8) rats and spontaneously hypertensive rats (SHR; n = 7). Isolated carotid sinus region...
Source: AJP: Regulatory, Integrative and Comparative Physiology - May 30, 2017 Category: Physiology Authors: Kawada, T., Turner, M. J., Shimizu, S., Fukumitsu, M., Kamiya, A., Sugimachi, M. Tags: Research Article Source Type: research