Revisiting the roles of protein synthesis during skeletal muscle hypertrophy induced by exercise.
Abstract Protein synthesis is deemed the underpinning mechanism enhancing protein balance required for skeletal muscle hypertrophy in response to resistance exercise. The current model of skeletal muscle hypertrophy induced by resistance training states that the acute increase in the rates of protein synthesis after each bout of resistance exercise is the basis for muscle growth. Within this paradigm, each resistance exercise session would add a specific amount of muscle mass; therefore, muscle hypertrophy could be defined as the result of intermittent and short-lived increases in muscle protein synthesis rates fo...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - September 11, 2019 Category: Physiology Authors: Figueiredo VC Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Oxygenation properties and underlying molecular mechanisms of hemoglobin in plateau zokor (Eospalax baileyi).
Abstract The plateau zokor (Eospalax baileyi) is a species of subterranean rodent endemic to the Tibetan Plateau. It's well adapted to the cold, hypoxic and hypercapnic burrow. In order to study the oxygenation properties of plateau zokor hemoglobins (Hbs), we measured intrinsic Hb-O2 affinities and their sensitivities to pH (Bohr effect), CO2, Cl-, 2,3-diphosphoglycerate (DPG) and temperature using purified Hbs from zokor and mouse. The optimal deoxyhemoglobin model of plateau zokor was constructed and used to study its structural characteristics by molecular dynamics simulations. O2-binding results revealed that...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - September 11, 2019 Category: Physiology Authors: Pu P, Lu S, Niu Z, Zhang T, Zhao Y, Yang X, Zhao Y, Tang X, Chen Q Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

The PVN Enhances Cardiorespiratory Responses to Acute Hypoxia via Input to the nTS.
Abstract Chemoreflex neurocircuitry includes the PVN, but the role of PVN efferent projections to specific cardiorespiratory nuclei is unclear. We hypothesized the PVN contributes to cardiorespiratory responses to hypoxia via projections to the nTS. Rats received bilateral PVN microinjections of AAV expressing inhibitory DREADD (GiDREADD) or GFP control. Efficacy of GiDREADD inhibition by the DREADD agonist Compound 21 (C21) was verified in PVN slices; C21 reduced evoked action potential discharge by reducing excitability to injected current in GiDREADD-expressing PVN neurons. We evaluated hypoxic ventilatory resp...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - September 11, 2019 Category: Physiology Authors: Ruyle BC, Martinez D, Heesch CM, Kline DD, Hasser EM Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Telemetric monitoring of penile pressure during mating in rats after chronic spinal cord injury.
Abstract In SCI males, erectile function, ejaculation, and fertility are severely impaired. The present study utilized a telemetric pressure transducer implanted into the corpus cavernosum of the penis to examine sexual function during awake mating behavior in a rat contusion model with a range of Infinite Horizon Impactor forces distributed between 150-215 kilodynes. The mating behavior paradigm included examination of the counts, average pressure, and average duration for mounts, intromissions, and ejaculations. Male Wistar rats were mated with receptive females in 30-minute sessions pre-injury (sexual acclimati...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - September 4, 2019 Category: Physiology Authors: Steadman CJ, Vangoor SS, Hubscher CH Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

The loss of hepatic PPAR α promotes inflammation and serum hyperlipidemia in diet-induced obesity.
The loss of hepatic PPARα promotes inflammation and serum hyperlipidemia in diet-induced obesity. Am J Physiol Regul Integr Comp Physiol. 2019 Sep 04;: Authors: Stec DE, Gordon DM, Hipp JA, Hong S, Mitchell ZL, Franco NR, Robison JW, Anderson CD, Stec DF, Hinds TD Abstract Agonists for PPARα are used clinically to reduce triglycerides and improve high-density lipoprotein (HDL) cholesterol levels in patients with hyperlipidemia. Whether the mechanism of PPARα activation to lower serum lipids occurs in the liver or other tissues is unknown. To determine the function of hepatic PPAR&alp...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - September 4, 2019 Category: Physiology Authors: Stec DE, Gordon DM, Hipp JA, Hong S, Mitchell ZL, Franco NR, Robison JW, Anderson CD, Stec DF, Hinds TD Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Impact of Acute Antioxidant Administration on Inflammation and Vascular Function in Heart Failure with Preserved Ejection Fraction.
CONCLUSION: Together, these data suggest acute AO administration can exert anti-inflammatory effects and improve conduit artery vasodilation, but not microvascular function, in patients with HFpEF. PMID: 31483155 [PubMed - as supplied by publisher] (Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology)
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - September 4, 2019 Category: Physiology Authors: Ratchford SM, Clifton HL, Gifford JR, La Salle DT, Thurston TS, Bunsawat K, Alpenglow JK, Richardson RS, Wright JB, Ryan JJ, Wray DW Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Heat therapy reduces sympathetic activity and improves cardiovascular risk profile in obese women with polycystic ovary syndrome.
Abstract Polycystic Ovary Syndrome (PCOS) affects up to 15% of women and is associated with increased risk of obesity and cardiovascular disease. Repeated passive heat exposure (termed 'heat therapy') is a lifestyle intervention with the potential to reduce cardiovascular risk in obesity and PCOS. Eighteen obese women with PCOS (Age: 27±4y, body mass index [BMI] 41.3±4.7 kg·m-2) were matched for age and BMI, then assigned to heat therapy (HT; n=9) or time control (CON; n=9). HT subjects underwent 30 one-hour hot tub sessions over 8-10 weeks, while CON subjects did not undergo heat therapy. Mus...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - September 4, 2019 Category: Physiology Authors: Ely BR, Francisco MA, Halliwill JR, Bryan SD, Comrada LN, Larson EA, Brunt VE, Minson CT Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Skeletal muscle amino acid uptake is lower and alanine production is greater in late gestation intrauterine growth restricted fetal sheep hindlimb.
Abstract In a sheep model of intrauterine growth restriction (IUGR) produced from placental insufficiency, late gestation fetuses had smaller skeletal muscle mass, myofiber area, and slower muscle protein accretion rates compared to normally growing fetuses. We hypothesized that IUGR fetal muscle develops adaptations that divert amino acids (AA) from protein accretion and activate pathways that conserve substrates for other organs. We placed hindlimb arterial and venous catheters into late gestation IUGR (n=10) and control (CON, n=8) fetal sheep and included an external iliac artery flow probe to measure hindlimb ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - September 4, 2019 Category: Physiology Authors: Chang EI, Wesolowski SR, Gilje EA, Baker PR, Reisz JA, D'Alessandro A, Hay WW, Rozance PJ, Brown LD Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Exercise stimulates beneficial adaptations to diminish doxorubicin-induced cellular toxicity.
Abstract Doxorubicin (DOX) is a highly effective antitumor agent used for the treatment of a wide range of cancers. Unfortunately, DOX treatment results in cytotoxic side effects due to its accumulation within off-target tissues. DOX-induced cellular toxicity occurs as a result of increased oxidative damage, resulting in apoptosis and cell death. While there is currently no standard of care practice to prevent DOX-induced toxicity to healthy organs, exercise has been shown to prevent cellular dysfunction when combined with DOX chemotherapy. Endurance exercise stimulates numerous biochemical adaptations that promot...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - August 28, 2019 Category: Physiology Authors: Smuder AJ Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Analysis of maximal expiratory flow-volume curves in adult survivors of preterm birth.
Abstract Adult survivors of very preterm (≤32 weeks gestational age)birth without (PRE) and with bronchopulmonary dysplasia (BPD) have variable degrees of airflow obstruction at rest. Assessment of the shape of the maximal expiratory flow-volume (MEFV) curve in PRE and BPD may provide information concerning their unique pattern of airflow obstruction. The purposes of the present study were to: i) quantitatively assess the shape of the MEFV curve in PRE, BPD, and healthy adults born at full-term (CON), ii) identify where along the MEFV curve differences in shape existed between groups, and iii) determine the ass...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - August 21, 2019 Category: Physiology Authors: Molgat-Seon Y, Dominelli PB, Peters CM, Guenette JA, Sheel AW, Gladstone IM, Lovering AT, Duke JW Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Progressive Exercise Training Improves Maximal Aerobic Capacity in Individuals with Well-Healed Burn Injuries.
Abstract Long term rehabilitative strategies are important for individuals with well-healed burn injuries. Such information is particularly critical because patients are routinely surviving severe burn injuries given medical advances in the acute care setting. The purpose of this study was to test the hypothesis that a 6-month community-based exercise training program will increase maximal aerobic capacity (V̇O2max) in subjects with prior burn injuries, with the extent of that increase influenced by the severity of the burn injury (i.e., percent body surface area burned). Maximal aerobic capacity (indirect calori...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - August 21, 2019 Category: Physiology Authors: Romero SA, Moralez G, Jaffery MF, Huang M, Cramer MN, Romain N, Kouda K, Haller RG, Crandall CG Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Cast immobilization of hindlimb upregulates sarcolipin expression in atrophied skeletal muscles and increases thermogenesis in C57BL/6J mice.
In this study, we investigated whether sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) itself or one of the regulators of the Ca2+ SERCA pump, sarcolipin (SLN), is altered to deregulate Ca2+ homeostasis in cast-immobilized, atrophied muscles. Hindlimb muscles of 8-week-old male C57BL/6J mice were subjected to bilateral cast immobilization for 2 weeks. Two-week cast-immobilization induced both body weight and skeletal muscle loss. Highly phosphorylated CaMKII in the atrophied muscles suggested that cytosolic Ca2+ concentration was elevated. Extremely high expression levels of SLN mRNA and protein were observed in the atroph...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - August 21, 2019 Category: Physiology Authors: Tomiya S, Tamura Y, Kouzaki K, Kotani T, Wakabayashi Y, Noda M, Nakazato K Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Impact of leptin deficiency compared to neuronal specific leptin receptor deletion on cardiometabolic regulation.
Abstract The main goal of this study was to compare the impact of total body leptin deficiency with neuronal specific leptin receptor (LR) deletion on metabolic and cardiovascular regulation. Liver fat, diacylglycerol acyltransferase-2 (DGTA2) and CD36 protein content were measured in wild-type (WT), nervous system LR deficient (LR/Nestin-Cre), and leptin deficient (ob/ob) mice. Blood pressure (BP) and heart rate (HR) were recorded by telemetry, and motor activity (MA) and oxygen consumption (VO2) were monitored at 24 weeks of age. Female and male LR/Nestin-Cre and ob/ob mice were heavier than WT mice (62±5...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - August 14, 2019 Category: Physiology Authors: do Carmo JM, da Silva AA, Gava FN, Moak SP, Dai X, Hall JE Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Skeletal muscle induce recruitment of Ly6C+ macrophages subtype and release inflammatory cytokines 3 days after downhill exercise.
Abstract Macrophages are one of the most versatile cells of the immune system, which can express distinct subtypes and functions depending on the physiological challenge. After skeletal muscle damage, inflammatory macrophages subtypes aids muscles to regeneration and are implicate on physical training adaption. Based on this, this study aimed to evaluate two classic mice macrophage subtypes, and some inflammatory cytokines might involve with muscle adaption process after exercise. For this purpose, mice were exposed to an intermittent experimental protocol of downhill exercise (18 bouts of running, each bout of 5 ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - August 14, 2019 Category: Physiology Authors: Minari ALA, Avila F, Oyama LM, Thomatieli-Santos RV Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Expression of obesity-related adipokine genes during fasting in a naturally obese marine mammal.
Abstract Northern elephant seals (Mirounga angustirostris) are exceptional among fasting-adapted animals in coupling prolonged fasting with energetically costly activities, relying on oxidation of fat stores accrued during foraging to power metabolic demands of reproduction and molting. We hypothesized that high rates of energy expenditure, insulin resistance, and immune responses to colonial breeding in fasting seals are mediated by adipokines, or signaling molecules secreted by adipose tissue that are associated with obesity and inflammation in humans. We measured mRNA expression of 10 adipokine genes in blubber...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - August 7, 2019 Category: Physiology Authors: Khudyakov JI, Abdollahi E, Ngo AL, Sandhu GK, Stephan AP, Costa DP, Crocker DE Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Corrigendum.
CORRIGENDUM. Am J Physiol Regul Integr Comp Physiol. 2019 Aug 01;317(2):R355 Authors: PMID: 31348694 [PubMed - in process] (Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology)
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - July 29, 2019 Category: Physiology Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Effect of knock out of the ASIC3 on cardiovascular reflexes arising from hindlimb muscle in decerebrated rats.
Abstract The exercise pressor reflex is initiated by the contraction-induced activation of group III and IV muscle afferents. The reflex is manifested by increases in arterial blood pressure and cardiac output, which, in turn, are generated by increases in the sympathetic outflow to the heart and vasculature and decreases in the vagal outflow to the heart. In previous experiments, we used a pharmacological approach to assess the role played by the Acid-Sensing Ion Channel 3 (ASIC3) on group III and IV afferents in evoking the exercise pressor reflex. In the present experiments, we used an alternative approach, nam...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - July 26, 2019 Category: Physiology Authors: Kim JS, Harms JE, Ruiz-Velasco VV, Kaufman MP Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Metabolomics of anoxia tolerance in D. melanogaster: evidence against substrate limitation and for roles of protective metabolites and paralytic hypometabolism.
Abstract Animals vary tremendously in their capacities to survive anoxia, and the mechanisms responsible are poorly understood. Adult Drosophila melanogaster are rapidly paralyzed and survive up to 12 h of anoxia, while larvae vigorously attempt escape but then die if anoxia exceeds 2 h. Here we use H-NMR methods to compare the metabolome of larvae and adult D. melanogaster under normoxic conditions and after various anoxic durations up to one hour. Glucose increased during anoxia in both larvae and adults, so anoxic death by carbohydrate limitation is unlikely for either stage. Lactate and alanine were the primar...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - July 19, 2019 Category: Physiology Authors: Campbell JB, Werkhoven S, Harrison JF Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Unsilencing of native leptin receptors (LepR) in hypothalamic SF1 neurons does not rescue obese phenotype in LepR-deficient mice.
Abstract Leptin receptor (LepR) signaling in neurons of the ventromedial nucleus of the hypothalamus (VMH), specifically those expressing steroidogenic factor-1 (SF1), have been proposed to play a key role in controlling energy balance. By crossing LepR-silenced (LepRloxTB) mice to those expressing SF1-Cre, we unsilenced native LepR specifically in the VMH and tested whether SF1 neurons in the VMH are critical mediators of leptin's effect on energy homeostasis. LepRloxTB x SF1-Cre (KO/Tg+) mice were metabolically phenotyped and compared to littermate controls that either expressed or were deficient in LepR. Leptin...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - July 17, 2019 Category: Physiology Authors: Senn SS, Le Foll C, Whiting L, Tarasco E, Duffy S, Lutz TA, Boyle CN Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Vascular Alpha-1 Adrenergic Sensitivity is Enhanced in Chronic Kidney Disease.
Abstract Chronic Kidney Disease (CKD) is often complicated by difficult-to-control hypertension, in part due to chronic overactivation of the sympathetic nervous system (SNS). CKD patients also exhibit a greater increase in arterial blood pressure for a given increase in sympathetic nerve activation, suggesting an augmented vasoconstrictive response to SNS activation (i.e. neurovascular transduction). One potential mechanism of increased sympathetic neurovascular transduction is heightened sensitivity of the vascular α1 adrenergic receptors (α1AR), the major effectors of vasoconstriction in response to...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - July 17, 2019 Category: Physiology Authors: Sprick JD, Morison DL, Stein CM, Li Y, Paranjape SY, Fonkoue IT, DaCosta DR, Park J Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

The Vitamin D-Folate Hypothesis in Human Vascular Health.
Abstract The vitamin D-folate hypothesis has been proposed as an explanation for the evolution of human skin pigmentation. According to this hypothesis, a darkened skin pigment was adapted by early human populations living in equatorial Africa to protect against photodegradation of bioavailable folate by ultraviolet radiation (UVR). As humans moved away from the equator to more northern latitudes and occupied regions of lower UVR exposure and greater seasonal variation, however, depigmentation occurred to allow for adequate biosynthesis of vitamin D. Vitamin D and folate are both recognized for their evolutionary ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - July 17, 2019 Category: Physiology Authors: Wolf ST, Kenney WL Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Inter-individual differences in the ischemic stimulus and other technical considerations when assessing reactive hyperemia.
Abstract Reactive hyperemia is an established, non-invasive technique to assess microvascular function, and is a powerful predictor of all-cause and cardiovascular morbidity and mortality. Emerging evidence from our lab suggests that reactive hyperemia is closely linked to the metabolic rate of the ischemic limb, and that large inter-individual differences exist, contributing to markedly different stimuli to vasodilate. Here we relate forearm tissue desaturation (i.e. the ischemic stimulus to vasodilate, measured by near-infrared spectroscopy) with brachial artery hyperemic velocity and flow (measured using duplex...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - July 17, 2019 Category: Physiology Authors: Rosenberry R, Trojacek D, Chung S, Cipher DJ, Nelson MD Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Increased Pyruvate Dehydrogenase Activity in Skeletal Muscle of Growth Restricted Ovine Fetuses.
Abstract Fetal sheep with placental insufficiency-induced intrauterine growth restriction (IUGR) have lower fractional rates of glucose oxidation and greater gluconeogenesis, indicating lactate shuttling between skeletal muscle and liver. Suppression of pyruvate dehydrogenase (PDH) activity was proposed because of greater pyruvate dehydrogenase kinase 4 (PDK4) and pyruvate dehydrogenase kinase 1 (PDK1) mRNA concentrations in IUGR muscle. Although PDK1 and PDK4 inhibit PDH activity to reduce pyruvate metabolism, PDH protein concentrations and activity have not been examined IUGR fetal skeletal muscle. Therefore, we...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - July 17, 2019 Category: Physiology Authors: Pendleton AL, Humphreys LR, Davis MA, Camacho LE, Anderson MJ, Limesand SW Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Alternate day feeding leads to improved glucose regulation on fasting days without significant weight loss in genetically obese mice.
Abstract Alternate day fasting (ADF) is effective for weight loss and increases insulin sensitivity in diet-induced obese rodents. However, the efficacy of ADF in genetic models of obesity has not been comprehensively studied. Mice that are deficient in leptin (ob/ob mice) are obese, diabetic, and are prone to deep bouts of torpor when fasted. We tested the hypotheses that an ADF protocol in ob/ob mice would result in 1) induction of torpor on fasted days, 2) minimal body weight loss if the mice experienced torpor, and 3) no improvement in glucose control in the absence of weight loss. Female ob/ob mice and litter...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - July 10, 2019 Category: Physiology Authors: Swoap SJ, Bingaman MJ, Hult EM, Sandstrom NJ Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Effects of whole-body skin cooling on human cognitive processing: A study using SEPs and ERPs.
Abstract The present study investigated the effect of whole-body skin cooling on somatosensory ascending processing by utilizing somatosensory-evoked potentials (SEPs) and motor execution as well as inhibitory processing by event-related potentials (ERPs). Fourteen healthy participants wearing a water-perfused suit performed two sessions (Sessions 1 and 2) consisting of SEPs and ERPs with somatosensory Go/No-go paradigms under two conditions (Cold stress and Control) on different days. In Session 2, under the Cold stress condition, whole-body skin cooling was achieved by circulating 20 °C water through the sui...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - July 10, 2019 Category: Physiology Authors: Nakata H, Kobayashi F, Lawley JS, Kakigi R, Shibasaki M Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Cyclooxygenase inhibition does not impact the pressor response during static or dynamic mechanoreflex activation in healthy decerebrate rats.
We examined the effect of rat triceps surae muscle stretch on the interstitial concentration of the COX metabolite prostaglandin E2 (PGE2). Four minutes of both static and dynamic triceps surae muscle stretch increased interstitial PGE2 concentration above baseline values (static: ↑38%, p=0.01, dynamic: ↑56%, p0.05, n=9) on the pressor or cardioaccelerator responses during 30 seconds of either static or dynamic stretch. We conclude that, despite skeletal muscle stretch-induced reductions in blood flow and the possibility of increased COX metabolite concentration, COX metabolites do not activate or sensitize thin ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - June 26, 2019 Category: Physiology Authors: Rollins KS, Hopkins TD, Butenas AL, Felice KP, Ade CJ, Copp SW Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Neurohumoral interactions contributing to renal vasoconstriction and decreased renal blood flow in heart failure.
Abstract In heart failure (HF), increases in renal sympathetic nerve activity (RSNA), renal norepinephrine spillover and renin release cause renal vasoconstriction, which may contribute to the cardiorenal syndrome. To increase our understanding of the mechanisms causing renal vasoconstriction in HF we investigated the interactions between the increased activity of the renal nerves and the renal release of norepinephrine and renin in an ovine pacing-induced model of HF. In addition, we determined the level of renal angiotensin type-1 receptors and the renal vascular responsiveness to stimulation of the renal nerves...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - June 26, 2019 Category: Physiology Authors: Ramchandra R, Xing DT, Matear M, Lambert G, Allen AM, May CN Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Interactions of mild hypothermia and hypoxia on finger vasoreactivity to local cold stress.
We examined the interactive effects of mild hypothermia and hypoxia on finger vasoreactivity to local cold stress. Eight male lowlanders performed, in a counterbalanced order, a normoxic and a hypoxic (PO2: ~12 kPa) hand cold provocation (consisting of a 30-min immersion in 8°C water), while immersed to the chest either in 21°C [cold trials; 0.5°C fall in rectal temperature (Trec) from individual pre-immersion values], or in 35.5°C water, or while exposed to 27°C air. The duration of the trials was kept constant in each breathing condition. Physiological (Trec, skin temperature, cutaneous vascular condu...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - June 26, 2019 Category: Physiology Authors: Keramidas ME, Kölegård R, Mekjavic IB, Eiken O Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Different vasodilator mechanisms in intermediate- and small-sized arteries from the hindlimb vasculature of the toad, Rhinella marina.
This study found that the mechanisms of vasodilation in the hindlimb vasculature of R. marina vary with vessel size, and that the endothelium is involved in vasodilation in the smaller sciatic artery. PMID: 31242019 [PubMed - as supplied by publisher] (Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology)
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - June 26, 2019 Category: Physiology Authors: Cameron MS, Donald JA Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

The Relationships Between Spinal CSF Flows, Spinal Cord Geometry and Vascular Correlations: Evidence of Intrathecal Sources and Sinks.
Abstract We studied relationships of Cerebral Spinal Fluid (CSF) pulsatile flow at cervical, thoracic and lumbar levels using Phase Contrast Cine Magnetic Resonance Imaging (PCCMRI) to determine: 1. Instantaneous and average net flows at cervical, thoracic and lumbar 2. Stochastic correlations of CSF flow with major arterial supplies and major draining veins. 3. If adjustments of cord flow curves using cord cross-sectional areas, caudal lengths and caudal volumes would normalizeflow curves from different levels. We scanned 15 healthy volunteers without anesthesia, ages 23-46 years, using external retrocardiac-gate...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - June 26, 2019 Category: Physiology Authors: Bert RJ, Settipalle N, Tiwana E, Muddasani D, Nath R, Wellman B, Mihlon FR, Negahdar MJ, Amini A, Boakye M Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

The regulation of catecholamine release from the adrenal medulla is altered in deer mice (Peromyscus maniculatus) native to high altitudes.
Abstract High-altitude natives have evolved to overcome environmental hypoxia and provide a compelling system to understand physiological function during reductions in oxygen availability. The sympathoadrenal system plays a key role in responses to acute hypoxia, but prolonged activation of this system in chronic hypoxia may be maladaptive. Here, we examined how chronic hypoxia exposure alters adrenal catecholamine secretion, and how adrenal function is altered further in high-altitude natives. Populations of deer mice (Peromyscus maniculatus) native to low and high altitude were each born and raised in captivity ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - June 26, 2019 Category: Physiology Authors: Scott AL, Pranckevicius NA, Nurse CA, Scott GR Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Mild hypothermia causes a shift in the alternative splicing of cold-inducible RNA-binding protein transcripts in Syrian hamsters.
Abstract Cold shock proteins are thought to participate in the cold-tolerant nature of hibernating animals. We previously demonstrated that an alternative splicing may allow rapid induction of functional cold-inducible RNA-binding protein (CIRBP)in the hamster heart. The purpose of the present study was to determine the major cause ofthe alternative splicing in Syrian hamsters.RT-PCR analysis revealed thatCIRBPmRNA is constitutively expressed in the heart, brain, lung, liver and kidney of non-hibernating euthermic hamsters with severalalternative splicing variants. In contrast, the short variant containing an open...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - June 12, 2019 Category: Physiology Authors: Horii Y, Shimaoka H, Horii K, Shiina T, Shimizu Y Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Skeletal muscle LINE-1 retrotransposon activity is upregulated in older versus younger rats.
Abstract Long Interspersed Element-1 (LINE-1) is a retrotransposon capable of replicating and inserting LINE-1 copies into the genome. Others have reported skeletal muscle LINE-1 markers are higher in older versus younger mice, but data are lacking in other species. Herein, gastrocnemius muscle from male Fischer 344 rats that were 3, 12, and 24 months (mo) (n=9 per group) were analyzed for LINE-1 mRNA, DNA, promoter methylation and DNA accessibility. qPCR primers were designed for active (L1.3) and inactive (L1.Tot) LINE-1 elements as well as part of the ORF1 sequence. L1.3, L1.Tot and ORF1 mRNAs were higher (p
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - June 12, 2019 Category: Physiology Authors: Mumford PW, Romero MA, Osburn SC, Roberson PA, Vann CG, Mobley CB, Brown MD, Kavazis AN, Young KC, Roberts MD Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Skeletal Muscle Energetics are Compromised Only During High Intensity Contractions in the Goto-Kakizaki Rat Model of Type 2 Diabetes.
Abstract Type 2 diabetes (T2D) presents with hyperglycemia and insulin resistance affecting over 30 million people in the US alone. Previous work has hypothesized that mitochondria are dysfunctional in T2D and results in both reduced ATP production and glucose disposal. However, a direct link between mitochondrial function and T2D has not been determined. In the current study, the Goto-Kakizaki (GK) rat model of T2D was used to quantify mitochondrial function in vitro and in vivo over a broad range of contraction-induced metabolic workloads. During high frequency sciatic nerve stimulation hindlimb muscle contracti...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - June 12, 2019 Category: Physiology Authors: Lewis MT, Kasper JD, Bazil JN, Frisbee JC, Wiseman RW Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

EDITORIAL: Editors' Picks for 2018, Demonstrate the Diversity of Research in Regulatory, Integrative and Comparative Physiology.
PMID: 31166690 [PubMed - as supplied by publisher] (Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology)
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - June 5, 2019 Category: Physiology Authors: Samson WK, Evans RG, Langhans W, Yosten GLC Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Blunted diuretic and natriuretic responses to acute sodium loading early after catheter-based renal denervation in normotensive sheep.
Abstract Catheter-based renal denervation (RDN) was introduced as a treatment for resistant hypertension. There remain critical questions regarding the physiological mechanisms underlying the hypotensive effects of catheter-based RDN. Previous studies indicate that surgical denervation reduces renin and the natriuretic response to saline loading; however, the effects on these variables of catheter-RDN, which does not yield complete denervation, are largely unknown. The aim of this study was to investigate the effects of catheter-RDN on glomerular-associated renin and regulation of fluid and sodium homeostasis in r...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - June 5, 2019 Category: Physiology Authors: McArdle Z, Pontes RB, Yao ST, Lankadeva YR, Singh RR, Hood SG, Schlaich MP, May CN, Booth LC Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Renal nerves and leukocyte infiltration in the kidney during salt-sensitive hypertension.
Abstract Based on previous studies suggesting a role of renal nerves in renal inflammation, the present studies were performed to test the hypothesis that renal nerves mediate renal damage in Dahl salt-sensitive (SS) hypertension by increasing renal leukocyte infiltration. Experiments were performed in Dahl SS rats using both bilateral renal denervation (RDN) or bilateral sham operation (n=10-11 per group); and using unilateral RDN and contralateral sham (n=10). Following denervation, rats were switched from a low salt 0.4% NaCl (LS) to a high salt 4% NaCl (HS) diet and maintained on HS for twenty-one days. Bilate...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - June 5, 2019 Category: Physiology Authors: Alsheikh AJ, Lund H, Dasinger JH, Abais-Battad JM, Fehrenbach DJ, Mattson DL Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Corrigendum.
Authors: PMID: 31111743 [PubMed - in process] (Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology)
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 23, 2019 Category: Physiology Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Corrigendum.
Authors: PMID: 31111744 [PubMed - in process] (Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology)
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 23, 2019 Category: Physiology Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Regulation of breathing pattern by IL-10.
Abstract Pro-inflammatory cytokines like interleukin-1β affect the control of breathing. Our aim is to determine the effect of the anti-inflammatory cytokine interleukin-10 (IL-10) οn the control of breathing. IL-10 knock-out mice (IL-10-/-, n=10) and wild type mice (IL-10+/+, n=10) were exposed to the following test gases: hyperoxic hypercapnia 7%CO2-93%O2, normoxic hypercapnia 7%CO2-21%O2, hypoxic hypercapnia 7%CO2-10%O2 and hypoxic normocapnia 3%CO2-10%O2. The ventilatory function was assessed using whole body plethysmography. Recombinant mouse IL-10 (rIL-10 10μg kg-1) was administered intraperi...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 15, 2019 Category: Physiology Authors: Giannakopoulou CE, Sotiriou A, Dettoraki M, Yang M, Perlikos F, Toumpanakis D, Prezerakos G, Koutsourelakis I, Kastis GA, Vassilakopoulou V, Mizi E, Apostolos P, Greer JJ, Vassilakopoulos T Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Habitual Cigarette Smoking Raises Pressor Responses to Spontaneous Bursts of Muscle Sympathetic Nerve Activity.
Abstract Smoking is a risk factor for cardiovascular diseases. Prior reports showed a transient increase in blood pressure following a spontaneous burst of muscle sympathetic nerve activity (MSNA). We hypothesized that this pressor response would be accentuated in smokers. Using signal averaging techniques, we examined the blood pressure (Finometer) response to MSNA in 18 otherwise healthy smokers and 42 healthy non-smokers during resting conditions. The sensitivities of baroreflex control of MSNA and heart rate were also assessed. The mean resting MSNA, heart rate and mean arterial pressure in smokers were higher...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 15, 2019 Category: Physiology Authors: Cui J, Drew RC, Muller MD, Blaha C, Gonzalez V, Sinoway LI Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Sex differences and the role of ovarian hormones in site-specific nociception of SHR rats.
Abstract The accurate diagnosis and treatment of pain is dependent upon the knowledge of variables that might alter this response. Some of these variables are the locality of the noxious stimulus, the sex of the individual, and the presence of chronic diseases. Among these chronic diseases, hypertension is considered a serious and silent disease that has been associated with hypoalgesia. The main goal of this study was to evaluate the potential nociceptive differences in spontaneously hypertensive rats (SHR) regarding the locality of the stimulus, i.e., the temporomandibular joint or paw, the sex, and the role of ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 15, 2019 Category: Physiology Authors: Maitan Santos B, Nascimento GC, Capel CP, Borges GS, Rosolen T, Sabino JPJ, Leite-Panissi CRA, Branco LGS Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Endothelium-dependent impairments to cerebral vascular reactivity with type ii diabetes mellitus in the goto-kakizaki rat.
ENDOTHELIUM-DEPENDENT IMPAIRMENTS TO CEREBRAL VASCULAR REACTIVITY WITH TYPE II DIABETES MELLITUS IN THE GOTO-KAKIZAKI RAT. Am J Physiol Regul Integr Comp Physiol. 2019 May 15;: Authors: Halvorson BD, Whitehead SN, McGuire JJ, Wiseman RW, Frisbee JC Abstract Type II diabetes mellitus (T2DM) is a prevalent pathology associated with elevated cerebrovascular disease risk. We determined wall mechanics and vascular reactivity in ex vivo middle cerebral arteries (MCA) from male Goto-Kakizaki rats (GK; (~17 week-old) versus control Wistar Kyoto rats (WKY), to test the hypothesis that diabetic environment in G...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 15, 2019 Category: Physiology Authors: Halvorson BD, Whitehead SN, McGuire JJ, Wiseman RW, Frisbee JC Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Exaggerated pressor and sympathetic responses to stimulation of the mesencephalic locomotor region and exercise pressor reflex in type II diabetic rats.
Abstract The cardiovascular responses to exercise are potentiated in patients with type 2 diabetes mellitus (T2DM). However, the underlying mechanisms causing this abnormality remain unknown. Central command (CC) and the exercise pressor reflex (EPR) are known to contribute significantly to cardiovascular control during exercise. Thus, these neural signals are viable candidates for the generation of the abnormal circulatory regulation in this disease. We hypothesized that augmentations in CC as well as EPR function contribute to the heightened cardiovascular responses during exercise in T2DM. To test this hypothes...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 15, 2019 Category: Physiology Authors: Kim HK, Hotta N, Ishizawa R, Iwamoto GA, Vongpatanasin W, Mitchell JH, Smith SA, Mizuno M Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Early Hyperbaric Oxygen Therapy Improves Survival in a Model of Severe Sepsis.
Abstract Sepsis is a major clinical challenge with therapy limited to supportive interventions. Therefore, the search for novel remedial approaches is of great importance. We addressed whether hyperbaric oxygen therapy (HBOT) could improve the outcome of sepsis using an acute experimental mouse model. Sepsis was induced in male CD-1 mice by cecal ligation and puncture (CLP) tailored to result in 80-90% mortality within 72h of the insult. After CLP, mice were randomized into two groups receiving HBOT or not at different times after the initial insult or subjected to multiple HBOT treatments. HBOT conditions were 98...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 15, 2019 Category: Physiology Authors: Halbach JL, Prieto JM, Wang AW, Hawisher D, Cauvi DM, Reyes T, Okerblom J, Ramirez-Sanchez I, Villarreal F, Patel HH, Bickler SW, Perdrizet GA, De Maio A Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

The separate and combined effects of KCa and KATP channel blockade with NOS inhibition on cutaneous vasodilation and sweating in older men during heat stress.
CONCLUSION: In habitually active older men, blockade of KCa and KATP channels attenuates cutaneous vasodilation during rest and exercise in the heat, respectively, and these effects are NOS-dependent. Furthermore, combined NOS inhibition and KCa channel blockade attenuates sweating during exercise in the heat. PMID: 31091157 [PubMed - as supplied by publisher] (Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology)
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 15, 2019 Category: Physiology Authors: McGarr GW, Fujii N, Muia CM, Nishiyasu T, Kenny GP Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Strain-dependent effects on lung structure, matrix remodeling and Stat3/Smad2 signaling in C57BL/6N and C57BL/6J mice after neonatal hyperoxia.
te;zar MA Abstract Bronchopulmonary dysplasia (BPD) is a chronic lung disease of preterm infants, characterized by lung growth arrest and matrix remodeling. Various animal models provide mechanistic insights in the pathogenesis of BPD. Since there is increasing evidence that genetic susceptibility modifies the response to lung injury, we investigated strain-dependent effects in hyperoxia-induced lung injury of newborn mice. To this end, we exposed newborn C57BL/6N and C57BL/6J mice to 85% O2 (HYX) or to 21% O2 (NOX) for 28 days, followed by lung excision for histological and molecular measurements. (1) BL/6J-NOX e...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 8, 2019 Category: Physiology Authors: Will JP, Hirani DV, Thielen F, Klein F, Vohlen C, Dinger K, Dötsch J, Alejandre-Alcázar MA Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Differential post-translational modification of mitochondrial enzymes corresponds with metabolic suppression during hibernation.
Abstract During hibernation, small mammals, including the 13-lined ground squirrel (Ictidomys tridecemlineatus), cycle between two distinct metabolic states: torpor, where metabolic rate is suppressed by>95% and body temperature falls to ~5 °C, and interbout euthermia (IBE), where both metabolic rate and body temperature rapidly increase to euthermic levels. Suppression of whole-animal metabolism during torpor is paralleled by rapid, reversible suppression of mitochondrial respiration. We hypothesized that these changes in mitochondrial metabolism are regulated by post-translational modifications to mitocho...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 8, 2019 Category: Physiology Authors: Mathers KE, Staples JF Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Glutamine synthetase in avian muscle contributes to a positive myogenic response to ammonia compared to mammalian muscle.
The objective of this study was to identify differences between avian and mammalian myogenic response to applied ammonia and glutamine. Primary chicken breast and thigh, primary rat, and C2C12 myotubes were treated with ammonium acetate (AA, 10mM) or glutamine (G, 10mM) for 24 hours, and compared to sodium acetate (SA, 10mM) and untreated (U) controls. Myostatin mRNA was significantly higher in C2C12 and rat myotubes treated with AA compared to G and controls (P
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 8, 2019 Category: Physiology Authors: Stern RA, Mozdziak PE Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Wnt signaling regulates cytosolic translocation of Connexin 43.
Abstract The availability of intracellular, stabilized ß-catenin, a transcription factor co-activator, is tightly regulated; ß-catenin is translocated into the nucleus in response to Wnt ligand binding to its cell membrane receptors. Here we show that Wnt signal activation in mammalian cells activates intracellular mobilization of Connexin 43 which belongs to a gap junction protein family, a new target protein in response to extracellular Wnt signal activation. Transmission electron microscopy (TEM) showed that the nuclear localization of Cx43 was increased by 8-10 fold in Wnt5A and 9B treated cells co...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - May 8, 2019 Category: Physiology Authors: Hou X, Khan MRA, Turmaine M, Thrasivoulou C, Becker DL, Ahmed A Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research