Stomach Region Stimulated Determines Effects on Duodenal Motility in Rats.
Abstract Gastric electrical stimulation (GES) is used clinically to promote proximal GI emptying and motility. In acute experiments, we measured duodenal motor responses elicited by GES applied at 141 randomly chosen electrode sites on the stomach serosal surface. Overnight-fasted (H2O available) anesthetized male rats (n = 81) received intermittent biphasic GES for 5 min (20s-on/40s-off cycles; I = 0.3mA; pw = 0.2ms; 10 Hz). A strain gauge on the serosal surface of the proximal duodenum of each animal was used to evaluate baseline motor activity and the effect of GES. Using ratios of time blocks compared to a 15-...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 20, 2021 Category: Physiology Authors: Tan ZT, Ward M, Phillips RJ, Zhang X, Jaffey DM, Chesney L, Rajwa B, Baronowsky EA, McAdams J, Powley TL Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

(pro)renin receptor in the kidney: function and significance.
(PRO)RENIN RECEPTOR IN THE KIDNEY: FUNCTION AND SIGNIFICANCE. Am J Physiol Regul Integr Comp Physiol. 2021 Jan 20;: Authors: Arthur G, Osborn JL, Yiannikouris FB Abstract Prorenin receptor (PRR), a 350-amino acid receptor initially thought of as a receptor for the binding of renin and prorenin has been shown to be multifunctional. In addition to its role in the renin angiotensin system (RAS), PRR also transduces several intracellular signaling molecules and is a component of the vacuolar H+-ATPase that participates in autophagy. PRR is found in the kidney and particularly in great abundance in the cor...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 20, 2021 Category: Physiology Authors: Arthur G, Osborn JL, Yiannikouris FB Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Chronic Hindbrain Administration of Oxytocin Elicits Weight Loss in Male Diet-Induced Obese Mice.
Abstract Previous studies indicate that oxytocin (OT) administration reduces body weight in high fat diet (HFD)-induced obese (DIO) rodents through both reductions in food intake and increases in energy expenditure. We recently demonstrated that chronic hindbrain [fourth ventricular (4V)] infusions of OT evoke weight loss in DIO rats. Based on these findings, we hypothesized that chronic 4V OT would elicit weight loss in DIO mice. We assessed the effects of 4V infusions of OT (16 nmol/day) or vehicle over 28 days on body weight, food intake and body composition. OT reduced body weight by approximately 4.5±1...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 20, 2021 Category: Physiology Authors: Edwards MM, Nguyen HK, Herbertson AJ, Dodson AD, Wietecha T, Wolden-Hanson T, Graham JL, O'Brien KD, Havel PJ, Blevins JE Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Mineralocorticoid receptors in the pathogenesis of insulin resistance and related disorders: From basic studies to clinical disease.
Abstract Aldosterone is a steroid hormone that regulates blood pressure and cardiovascular function by acting on renal and vascular mineralocorticoid receptors (MRs) to promote sodium retention and modulate endothelial function. Indeed, MRs are expressed in endothelial cells, vascular smooth muscle cells, adipocytes, immune cells, skeletal muscle cells, and cardiomyocytes. Excessive aldosterone and associated MR activation impair insulin secretion, insulin metabolic signaling to promote development of diabetes and the related cardiometabolic syndrome. These adverse effects of aldosterone are mediated, in part, via...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 13, 2021 Category: Physiology Authors: Jia G, Lockette W, Sowers JR Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Effects of Salt Intake on Sympathetic Neural and Pressor Responses to Cold Pressor Test in Premenopausal Women with A History of Normal Pregnancy.
This study aimed to determine whether salt loading versus salt reduction would impact hemodynamic and sympathetic neural responses during the cold pressor test (CPT) in premenopausal women with a history of normal pregnancy. Nine healthy premenopausal women [42±3 (SD) yr] were given a standardized isocaloric high salt (HS; 250 mEq sodium/day) or low salt (LS; 50 mEq sodium/day) diet for 1-week each (~2 months apart with the order randomized), while water intake was ad libitum. Laboratory testing was performed following each HS and LS period in the mid-luteal phase of the menstrual cycle. Subjects were in the supine ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 13, 2021 Category: Physiology Authors: Takeda R, Stickford ASL, Best SA, Yoo JK, Liu YL, Fu Q Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Vascular Function in Continuous-Flow Left Ventricular Assist Device Recipients: Effect of a Single Pulsatility Treatment Session.
Abstract BACKGROUND: Vascular function is further attenuated in chronic heart failure patients implanted with a continuous-flow left ventricular assist device (LVAD), likely due to decreased arterial pulsatility, and this may contribute to LVAD-associated cardiovascular complications. However, the impact of increasing pulsatility on vascular function in this population is unknown. METHODS: Therefore, fifteen LVAD recipients and fifteen well-matched controls, underwent a 45-minute, unilateral, arm pulsatility treatment, evoked by intermittent cuff inflation/deflation (2-second duty cycle), distal to the elbow....
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 13, 2021 Category: Physiology Authors: Hydren JR, Gifford JR, Jarrett CL, Park SH, Shields KL, Broxterman RM, Kithas AC, Bisconti AV, Thurston TS, Ratchford SM, Wray DW, Stehlik J, Selzman CH, Drakos SG, Richardson RS Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Dissociable effects of dietary sodium in early life upon somatic growth, fluid homeostasis, and spatial memory in mice of both sexes.
Abstract Postnatal growth failure is a common morbidity for preterm infants and is associated with adverse neurodevelopmental outcomes. While sodium (Na) deficiency early in life impairs somatic growth, its impact on neurocognitive functions have not been extensively studied. We hypothesized that Na deficiency during early life is sufficient to cause growth failure and program neurobehavioral impairments in later life. C57BL/6J mice were placed on low (0.4), normal (1.5), or high (3 g/kg) Na chow at weaning (PD22) and continued on the diet for 3 weeks (to PD40). Body composition and fluid distribution were determi...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 13, 2021 Category: Physiology Authors: Segar JL, Grobe CC, Balapattabi K, Ritter ML, Reho JJ, Grobe JL Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

The role of astrocytes in the nucleus Tractus Solitarii in maintaining central control of autonomic function.
Abstract The nucleus Tractus Solitarii (nTS) is the first central site for the termination and integration of autonomic and respiratory sensory information. Sensory afferents terminating in the nTS as well as the embedded nTS neurocircuitry release and utilize glutamate that is critical for maintenance of baseline cardiorespiratory parameters and initiating cardiorespiratory reflexes, including those activated by bouts of hypoxia. nTS astrocytes contribute to synaptic and neuronal activity through a variety of mechanisms, including gliotransmission and regulation of glutamate in the extracellular space via membran...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 13, 2021 Category: Physiology Authors: Martinez D, Kline DD Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Unique inflammatory profile is associated with higher SARS-CoV-2 acute respiratory distress syndrome (ARDS) mortality.
Abstract The COVID19 pandemic has caused more than a million of deaths worldwide, primarily due to complications from COVID19-associated acute respiratory distress syndrome (ARDS). Controversy surrounds the circulating cytokine/chemokine profile of COVID19-associated ARDS, with some groups suggesting that it is similar to non-COVID19 ARDS patients and others observing substantial differences. Moreover, while a hyperinflammatory phenotype associates with higher mortality in non-COVID19 ARDS, there is little information on the inflammatory landscape's association with mortality in COVID19 ARDS patients. Even though ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 12, 2021 Category: Physiology Authors: Balnis J, Adam AP, Chopra A, Chieng HC, Drake LA, Martino N, Bossardi Ramos R, Feustel PJ, Overmyer KA, Shishkova E, Coon JJ, Singer HA, Judson MA, Jaitovich A Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Activation of G Protein-Coupled Estrogen Receptor 1 Ameliorates Proximal Tubular Injury and Proteinuria in Dahl Salt-Sensitive Female Rats.
Abstract Recent evidence indicates a crucial role for G protein-coupled estrogen receptor 1 (GPER1) in the maintenance of cardiovascular and kidney health in females. The current study tested whether GPER1 activation ameliorates hypertension and kidney damage in female Dahl salt-sensitive (SS) rats fed a high-salt (HS) diet. Adult female rats were implanted with telemetry transmitters for monitoring blood pressure and osmotic minipumps releasing G1 (selective GPER1 agonist, 400 μg/kg/day, intraperitoneal) or vehicle. Two weeks after pump implantation, rats were shifted from a normal salt diet (NS, 0.4% NaCl) to...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 6, 2021 Category: Physiology Authors: Gohar EY, Almutlaq RN, Daugherty EM, Butt MK, Jin C, Pollock JS, Pollock DM, De Miguel C Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Exogenous GLP-1 Stimulates TCA Cycle and Suppresses Gluconeogenesis and Ketogenesis in Late-fasted Northern Elephant Seals Pups.
Abstract The post-weaning fast of northern elephant seal pups is characterized by a lipid-dependent metabolism and associated with a decrease in plasma glucagon-like peptide-1 (GLP-1), insulin, and glucose and increased gluconeogenesis (GNG) and ketogenesis. We have also demonstrated that exogenous GLP-1 infusion increased plasma insulin despite simultaneous increases in cortisol and glucagon, which collectively present contradictory regulatory stimuli of GNG, ketogenesis, and glycolysis. To assess the effects of GLP-1 on metabolism using primary carbon metabolite profiles in late-fasted seal pups, we dose-depende...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 6, 2021 Category: Physiology Authors: Dhillon J, Viscarra JA, Newman JW, Fiehn O, Crocker DE, Ortiz RM Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Type I diabetes suppresses intracellular calcium ion increase normally evoked by heat stress in rat skeletal muscle.
Abstract Heat stress, via its effects on muscle intracellular Ca2+ concentrations ([Ca2+]i), has been invoked as a putative therapeutic countermeasure to Type 1 diabetes-induced muscle atrophy. Using in vivo muscle preparation we tested the hypothesis that impaired muscle Ca2+ homeostasis in type I diabetic rats is due to attenuated heat stress tolerance mediated via TRPV1. Male Wistar rats were assigned to 1 of 4 groups: 1.control 30oC (CONT 30oC), 2.CONT 40oC, 3.diabetes 30oC (DIA 30oC), 4.DIA 40oC. 40oC was selected because it just exceeds the TRPV1 activation threshold. Spinotrapezius muscles were exteriorized...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - January 6, 2021 Category: Physiology Authors: Ikegami R, Eshima H, Nakajima T, Toyoda S, Poole DC, Kano Y Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

The effect of estimating chest wall compliance on the work of breathing during exercise as determined via the modified Campbell diagram.
Abstract The modified Campbell diagram provides one of the most comprehensive assessments of the work of breathing (Wb) during exercise, wherein the resistive and elastic work of inspiration and expiration are quantified. Importantly, a necessary step in constructing the modified Campbell diagram is to obtain a value for chest wall compliance (CCW). To date, it remains unknown whether estimating or directly measuring CCW impacts on the Wb as determined by the modified Campbell diagram. Therefore, the purpose of this study was to evaluate whether the components of the Wb differ when the modified Campbell diagram is...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - December 23, 2020 Category: Physiology Authors: Gideon EA, Cross TJ, Coriell CL, Duke JW Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Species-specific metabolic responses of songbird, shorebird, and murine cultured myotubes to N-3 polyunsaturated fatty acids.
Abstract Migratory birds may benefit from diets rich in polyunsaturated fatty acids (PUFA) that could improve exercise performance. Previous investigations suggest that different types of birds may respond differently to PUFA. We established muscle myocyte cell culture models from muscle satellite cells of a migratory passerine songbird (yellow-rumped warbler, Setophaga coronata coronata) and a non-passerine shorebird (sanderling, Calidris alba). We differentiated and treated avian myotubes and immortalized murine C2C12 myotubes with n-3 PUFA docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), and with mon...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - December 23, 2020 Category: Physiology Authors: Young KG, Vanderboor CM, Regnault TRH, Guglielmo CG Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Exercise alters cardiovascular and renal pregnancy adaptations in female rats born small on a high-fat diet.
This study determined if high-fat-feeding exacerbates the known adverse cardiorenal adaptations to pregnancy in rats born small and whether endurance exercise can prevent these complications. Uteroplacental insufficiency was induced by bilateral uterine vessel ligation (Restricted) or sham (Control) surgery on embryonic day 18 (E18) in Wistar-Kyoto rats. Female offspring consumed a Chow or High-fat-diet (HFD) from weaning and were randomly allocated an exercise protocol at 16 weeks; Sedentary, Exercised before and during pregnancy (Exercise), or Exercised during pregnancy only (PregEx). Systolic blood pressure was measured...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - December 16, 2020 Category: Physiology Authors: Mahizir D, Briffa JF, Anevska K, Wadley GD, Mortiz KM, Wlodek ME Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Measurement of fetal parasympathetic activity during labor: a new pathway for evaluation of fetal well-being?
ian C PMID: 33326344 [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 - December 16, 2020 Category: Physiology Authors: Ghesquière L, De Jonckheere J, Storme L, Garabedian C Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

A Protective Role of SOD1 Overexpression in Central Mediation of Bradycardia Following Chronic Intermittent Hypoxia in Mice.
In this study, we used mice as a model to examine the effects of CIH on baroreflex sensitivity, aortic baroreceptor afferents and central and vagal efferent components of the baroreflex circuitry. Furthermore, we tested whether human Cu/Zn Superoxide Dismutase (SOD1) overexpression in the transgenic mice offers protection against CIH induced deficit of the baroreflex arc. Wild-type C57BL/6J and SOD1 mice were exposed to room air (RA) or CIH and were then anesthetized, ventilated and catheterized for measurement of mean arterial pressure (MAP) and HR. Compared with wild-type RA control, CIH impaired baroreflex sensitivity b...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - December 9, 2020 Category: Physiology Authors: Chen J, Gu H, Wurster RD, Cheng ZJ Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Intranasal Oxytocin has sympathoexcitatory effects on vascular tone in healthy males.
Abstract OBJECTIVE: Oxytocin appears to be involved in the neuroendocrine regulation of sympathetic blood pressure (BP) homeostasis. In animals, intracerebral administration of oxytocin induces BP-relevant sympathetic activation. In humans, central nervous effects of oxytocin on BP regulation remain unclear. Intranasal administration supposedly delivers oligopeptides like oxytocin directly to the brain. We investigated the effects of intranasal oxytocin on sympathetic vascular baroreflex function in humans using microneurographic techniques. METHODS: In a balanced, double-blind cross-over design oxytocin or p...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - December 9, 2020 Category: Physiology Authors: Meusel M, Herrmann M, Machleidt F, Franzen K, Vonthein R, Sayk F Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Blunted sweating does not alter the rise in core temperature in people with multiple sclerosis exercising in the heat.
CONCLUSION: Even at 35˚C, a delayed sweating onset didn't alter heat loss to sufficiently affect exercise-induced rises in core temperature. Heat intolerance with MS does not seem attributable to thermoregulatory impairments. PMID: 33296279 [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 - December 9, 2020 Category: Physiology Authors: Chaseling GK, Filingeri D, Allen DR, Barnett M, Vucic S, Davis SL, Jay O Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Pre-locus coeruleus neurons in rat and mouse.
Abstract Previously, we identified a population of neurons in the hindbrain tegmentum, bordering the locus coeruleus (LC). We named this population the pre-locus coeruleus (pre-LC) because in rats its neurons lie immediately rostral to the LC. In mice, however, pre-LC and LC neurons intermingle, making them difficult to distinguish. Here we use molecular markers and anterograde tracing to clarify the location and distribution of pre-LC neurons in mice, relative to rats. First, we co-localized the transcription factor FoxP2 with the activity marker Fos to identify pre-LC neurons in sodium-deprived rats and show the...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - December 9, 2020 Category: Physiology Authors: Gasparini S, Resch JM, Gore AM, Peltekian L, Geerling JC Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

The complex role of Prostaglandin E2-EP receptor signaling in wound healing.
Abstract Prostaglandins are critical lipid mediators involved in the wound healing response, with prostaglandin E2 (PGE2) being the most complex and exhibiting the most diverse physiological outputs. PGE2 signals via four G-protein coupled receptors, termed EP-receptors 1-4, that induce distinct signaling pathways upon activation and lead to an array of different outputs. Recent studies examining the role of PGE2 and EP receptor signaling in wound healing following various forms of tissue damage are discussed in this review. PMID: 33296281 [PubMed - as supplied by publisher] (Source: American Journal of Physi...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - December 9, 2020 Category: Physiology Authors: Gilman KE, Limesand KH Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

V1a and V1b Vasopressin Receptors Within the Paraventricular Nucleus Contribute to Hypertension in Male Rats Exposed to Chronic Mild Unpredictable Stress.
Abstract Depression is an independent non-traditional risk factor for cardiovascular disease and mortality. The chronic unpredictable mild stress (CMS) rat model is a validated model of depression. Within the paraventricular nucleus (PVN), vasopressin (VP) via V1aR and V1bR have been implicated in stress and neurocardiovascular dysregulation. We hypothesized that in conscious, unrestrained CMS rats vs control, unstressed rats, PVN VP results in elevated arterial pressure (MAP), heart rate and renal sympathetic nerve activity (RSNA) via activation of V1aR and/or V1bR. Male rats underwent four weeks of CMS or contro...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - December 2, 2020 Category: Physiology Authors: Komnenov D, Quaal H, Rossi NF Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Chronic CNS-mediated cardiometabolic actions of leptin: potential role of sex differences.
We examined potential sex differences in leptin's chronic central nervous system (CNS)-mediated actions on blood pressure (BP), heart rate (HR), appetite, and glucose homeostasis in normal and type 1 diabetic rats. Female (n=6) and male (n=5) Sprague-Dawley rats were instrumented with intracerebroventricular (ICV) cannulas for continuous 7-day leptin infusion (15 mg/day) and BP and HR were measured by telemetry 24-hrs/day. At baseline, females had lower MAP (96±3 vs. 104±4 mmHg, p
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 18, 2020 Category: Physiology Authors: da Silva AA, Pinkerton MA, Spradley FT, Palei AC, Hall JE, do Carmo JM Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Signaling in Rat Brainstem via Gpr160 is Required for the Anorexigenic and Antidipsogenic Actions of Cocaine- and Amphetamine-Regulated Transcript Peptide.
Abstract Recent work identified Gpr160 as a candidate receptor for cocaine- and amphetamine-regulated transcript peptide (CARTp) and described its role in pain modulation. The aims of the present study were to determine if Gpr160 is required for the CARTp's ability to reduce food and water intake and to initially identify the distribution of Gpr160-like immunoreactivity (Gpr160ir) in the rat brain. A passive immunoneutralization approach targeting Gpr160 was used to block the behavioral effects of a pharmacologic dose of CARTp in the fourth cerebroventricle (4V) of rats and to determine the importance of endogenou...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 18, 2020 Category: Physiology Authors: Haddock CJ, Almeida-Pereira G, Stein LM, Hayes MR, Kolar GR, Samson WK, Yosten GLC Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Consuming sucrose solution promotes leptin resistance and site specifically modifies hypothalamic leptin signaling in rats.
This study tested whether leptin resistance in LiqS rats extended beyond a failure to inhibit food intake and examined leptin responsiveness in the hypothalamus and hindbrain of rats offered HS, LiqS or a sucrose free diet (NS). Female LiqS Sprague Dawley rats initially only partially compensated for the calories consumed as sucrose, but energy intake matched that of HS and NS rats when they were transferred to calorimetry cages. There was no effect of diet on energy expenditure, IBAT temperature or fat pad weight. A peripheral injection of 2 mg leptin/kg on Day 23 or 26 inhibited energy intake of HS and NS, but not LiqS r...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 18, 2020 Category: Physiology Authors: Harris RBS Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Activation of the carotid body increases directly recorded cardiac sympathetic nerve activity and coronary blood flow in conscious sheep.
Abstract Activation of the carotid body (CB) using intracarotid potassium cyanide (KCN) injection increases coronary blood flow (CoBF). This increase in CoBF is considered to be mediated by co-activation of both the sympathetic and parasympathetic nerves to the heart. However, whether cardiac sympathetic nerve activity (cardiac SNA) actually increases during CB activation has not been determined previously. We hypothesized that activation of the CB would increase directly recorded cardiac SNA, which would cause coronary vasodilatation. Experiments were conducted in conscious sheep implanted with electrodes to reco...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 18, 2020 Category: Physiology Authors: Pachen M, Abukar Y, Shanks J, Lever N, Ramchandra R Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Skeletal Muscle Extracellular Matrix Remodeling with Worsening Glycemic Control in Nonhuman Primates.
This report supports that rising blood glucose values incite ECM remodeling and reduce SkM capillarization, and that targeting ECM would be a rational approach to improve health with metabolic disease. PMID: 33206559 [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 - November 18, 2020 Category: Physiology Authors: Ruggiero AD, Davis A, Sherrill C, Westwood B, Hawkins GA, Palmer ND, Chou JW, Reeves T, Cox LA, Kavanagh K Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

In vivo Ca2+ dynamics during cooling after eccentric contractions in rat skeletal muscle.
Abstract The effect of cooling on in vivo intracellular calcium ion concentration ([Ca2+]i) after eccentric contractions (ECs) remains to be determined. We tested the hypothesis that cryotherapy following ECs promotes an increased [Ca2+]i and induces greater muscle damage in two muscles with substantial IIb and IIx fiber populations. The thin spinotrapezius (SPINO) muscles of Wistar rats were used for in vivo [Ca2+]i imaging and tibialis anterior (TA) muscles provided greater fidelity and repeatability of contractile function measurements. SPINO [Ca2+]i was estimated using fura 2-AM and the magnitude, location and...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 18, 2020 Category: Physiology Authors: Takagi R, Tabuchi A, Asamura T, Hirayama S, Ikegami R, Tanaka Y, Hoshino D, Poole DC, Kano Y Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Neuromodulation or energy failure? Metabolic limitations silence network output in the hypoxic amphibian brainstem.
Abstract Hypoxia tolerance in the vertebrate brain often involves chemical modulators that arrest neuronal activity to conserve energy. However, in intact networks, it can be difficult to determine whether hypoxia triggers modulators to stop activity in a protective manner or whether activity stops because rates of ATP synthesis are insufficient to support network function. Here, we assessed the extent to which neuromodulation or metabolic limitations arrest activity in the respiratory network of bullfrogs-a circuit that survives moderate periods of oxygen deprivation, presumably, by activating an inhibitory norad...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 11, 2020 Category: Physiology Authors: Adams S, Zubov T, Bueschke N, Santin JM Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Stimulation of Soluble Guanylate Cyclase Diminishes Intrauterine Growth Restriction in a Rat Model of Placental Ischemia.
Abstract Placental ischemia in preeclampsia (PE) results in hypertension and intrauterine growth restriction (IUGR). Stimulation of soluble guanylate cyclase (sGC) reduces blood pressure in the clinically relevant reduced uterine perfusion pressure (RUPP) rat model of PE implicating involvement in RUPP-induced hypertension. However, the contribution of sGC in the development of IUGR in PE is not known. Thus, this study demonstrated the efficacy of Riociguat, a sGC stimulator, in IUGR reversion in the RUPP rat model of PE, and tested the hypothesis that improvement in fetal weight occurs in association with improve...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 11, 2020 Category: Physiology Authors: Coats LE, Bamrick-Fernandez DR, Ariatti AM, Bakrania BA, Rawls AZ, Ojeda NB, Alexander BT Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Characterisation of the circulating and tissue-specific alterations to the lipidome in response to moderate and major cold stress in mice.
This study analysed the effects of 24 hours of cold stress (22°C or 5°C vs. mice maintained at 30°C) on the plasma, brown adipose tissue (BAT), subcutaneous (SubQ) and epididymal (Epi) white adipose tissue (WAT), liver, and skeletal muscle lipidome of mice. Using mass spectrometry-lipidomics 624 lipid species were detected, of which 239 were significantly altered in plasma, 134 in BAT, and 51 in the liver. In plasma, acylcarnitines and free fatty acids were markedly increased at 5°C. Plasma triacylglycerols (TGs) were reduced at 22°C and 5°C. We also identified ether lipids as a novel, cold-induced ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 11, 2020 Category: Physiology Authors: Pernes G, Morgan PK, Huynh K, Mellett NA, Meikle PJ, Murphy AJ, Henstridge DC, Lancaster GI Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Dietary adaptation to high starch involves increased relative abundance of sucrase-isomaltase and its mRNA in nestling house sparrows.
Abstract Dietary flexibility in digestive enzyme activity is widespread in vertebrates, but mechanisms are poorly understood. When laboratory rats are switched to higher carbohydrate diet, activity of intestinal sucrase-isomaltase (SI) increases within 6-12 h, mainly by rapid increase in enzyme transcription followed by rapid translation and translocation to the intestine's apical, brush border membrane (BBM). We performed the first unified study of the overall process in birds, relying on activity, proteomic and transcriptomic data from nestling house sparrows (Passer domesticus). They switch naturally from low-s...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 11, 2020 Category: Physiology Authors: Brun A, Magallanes ME, Barrett-Wilt GA, Karasov WH, Caviedes-Vidal E Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Bladder Underactivity Induced by Prolonged Pudendal Afferent Activity in Cats.
Abstract The purpose of this study is to determine the effects of pudendal nerve stimulation (PNS) on reflex bladder activity and develop an animal model of underactive bladder (UAB). In six anesthetized cats, a bladder catheter was inserted via the urethra to infuse saline and measure pressure. A cuff electrode was implanted on the pudendal nerve. After determining the threshold intensity (T) for PNS to induce an anal twitch, PNS (5 Hz, 0.2 ms, 2T or 4T) was applied during cystometrograms (CMGs). PNS (4-6T) of 30-min duration was then applied repeatedly until bladder underactivity was produced. Following stimulat...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 4, 2020 Category: Physiology Authors: Mohapatra A, Chen J, Zhao J, Zhong Y, Armann K, Shen B, Wang J, Beckel J, de Groat WC, Tai C Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Impact of chorionic somatomammotropin rna interference on uterine blood flow and placental glucose uptake in the absence of intrauterine growth restriction.
IMPACT OF CHORIONIC SOMATOMAMMOTROPIN RNA INTERFERENCE ON UTERINE BLOOD FLOW AND PLACENTAL GLUCOSE UPTAKE IN THE ABSENCE OF INTRAUTERINE GROWTH RESTRICTION. Am J Physiol Regul Integr Comp Physiol. 2020 Nov 04;: Authors: Tanner AR, Lynch CS, Ali A, Winger QA, Rozance PJ, Anthony RV Abstract Chorionic Somatomammotropin (CSH) is one of the most abundantly produced placental hormones, yet its exact function remains elusive. Near-term (135 dGA), CSH RNA interference (RNAi) results in two distinct phenotypes: 1) pregnancies with intrauterine growth restriction (IUGR), and 2) pregnancies with normal fetal an...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 4, 2020 Category: Physiology Authors: Tanner AR, Lynch CS, Ali A, Winger QA, Rozance PJ, Anthony RV Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Minireview: The involvement of renal afferents in the maintenance of cardiorenal diseases.
Abstract Elevated sympathetic vasomotor activity is a common feature of cardiorenal diseases. Therefore, the sympathetic nervous system is an important therapeutic target, particularly the fibers innervating the kidneys. In fact, renal denervation has been applied clinically and shown promising results in patients with hypertension and chronic kidney disease. However, the underlying mechanisms involved in the cardiorenal protection induced by renal denervation have not yet been fully clarified. This mini-review highlights historical and recent aspects related to the role of renal sensory fibers in the control of c...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 4, 2020 Category: Physiology Authors: Veiga AC, Milanez MIO, Campos RR, Bergamaschi CT, Nishi EE Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Impaired cardiorespiratory responses to hypercapnia in neonatal mice lacking PAC1 but not VPAC2 receptors.
In this study, we investigated whether the PACAP receptors, PAC1 or VPAC2, are involved in the neonatal cardiorespiratory response to hypercapnic stress. We used head-out plethysmography and surface ECG electrodes to assess cardiorespiratory responses to an 8% hypercapnic challenge in unanesthetized and spontaneously breathing 4 days old PAC1 or VPAC2 knockout (KO) and wildtype (WT) mouse pups. We demonstrate that compared to WTs, breathing frequency (RR) and minute ventilation () in PAC1 KO pups were significantly blunted in response to hypercapnia. Although heart rate was unaltered in PAC1 KO pups during hypercapnia, hea...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - November 4, 2020 Category: Physiology Authors: Barrett KT, Hasan SU, Scantlebury MH, Wilson RJA Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Hypoxic Modulation of Fetal Vascular MLCK Abundance, Localization, and Function.
Abstract Changes in vascular contractility are among the most important physiological effects of acute and chronic fetal hypoxia. Given the essential role of Myosin Light Chain Kinase (MLCK) in smooth muscle contractility, and its heterogeneous distribution, this study explores the hypothesis that subcellular changes in MLCK distribution contribute to hypoxic modulation of fetal carotid artery contractility. Relative to common carotid arteries from normoxic term fetal lambs (FN), carotids from fetal lambs gestated at high altitude (3802m) (FH) exhibited depressed contractility without changes in MLCK mRNA or prote...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 28, 2020 Category: Physiology Authors: Sorensen DW, Carreon D, Williams JM, Pearce WJ Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Plasma brain-derived neurotrophic factor and dynamic cerebral autoregulation in acute response to glycemic control following breakfast in young men.
We examined the acute impact of both low- and high-glycemic index (GI) breakfasts on plasma brain-derived neurotrophic factor (BDNF) and dynamic cerebral autoregulation (dCA) compared to breakfast omission. Ten healthy men (age 24 ± 1 yrs) performed three trials in a randomized crossover order; omission, Low- (GI = 40), and High-GI (GI = 71) breakfast conditions. Middle cerebral artery velocity (transcranial Doppler ultrasonography) and arterial pressure (finger photoplethysmography) were continuously measured for 5-mins prior to and 120-mins following breakfast consumption, to determine dCA using transfer function ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 28, 2020 Category: Physiology Authors: Tsukamoto H, Ishibashi A, Marley CJ, Shinohara Y, Ando S, Bailey DM, Hashimoto T, Ogoh S Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Proteomic analysis of mitochondrial biogenesis in cardiomyocytes differentiated from human induced pluripotent stem cells.
Abstract Mitochondria play key roles in the differentiation and maturation of human cardiomyocytes (CMs). As human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) hold potential in the treatment of heart diseases, we sought to identify key mitochondrial pathways and regulators, which may provide targets for improving cardiac differentiation and maturation. Proteomic analysis was performed on enriched mitochondrial protein extracts isolated from hiPSC-CMs differentiated from dermal fibroblasts (dFCM) and cardiac fibroblasts (cFCM) at time points between 12 and 115 days of differentiation, and from ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 28, 2020 Category: Physiology Authors: Venkatesh S, Baljinnyam E, Tong M, Kashihara T, Yan L, Liu T, Li H, Xie LH, Nakamura M, Oka S, Suzuki C, Fraidenraich D, Sadoshima J Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Aging and chronic high-fat feeding negatively affects kidney size, function, and gene expression in CTRP1-deficient mice.
Abstract C1q/TNF-related protein 1 (CTRP1) is an endocrine factor with metabolic, cardiovascular, and renal functions. We previously showed that aged Ctrp1 knockout (KO) mice fed a control low-fat diet develop renal hypertrophy and dysfunction. Since aging and obesity adversely affects various organ systems, we hypothesized that aging, in combination with obesity induced by chronic high-fat feeding, would further exacerbates renal dysfunction in CTRP1-deficient animals. To test this, we fed wild-type and Ctrp1 KO mice a high-fat diet for eight months or longer. Contrary to our expectation, no differences were obse...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 21, 2020 Category: Physiology Authors: Rodriguez S, Little HC, Daneshpajouhnejad P, Fenaroli P, Tan SY, Sarver DC, Delannoy M, Talbot CC, Jandu S, Berkowitz DE, Pluznick JL, Rosenberg AZ, Wong GW Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Spectrum of Myelinated Pulmonary Afferents (III) Cracking Intermediate Adapting Receptors.
Abstract Conventional one-sensor theory (one afferent fiber connects to a single sensor) categorizes the bronchopulmonary mechanosensors into the rapidly adapting receptors (RARs), slowly adapting receptors (SARs), or intermediate adapting receptors (IARs). RARs and SARs are known to sense the rate and magnitude of mechanical change, respectively; however, there is no agreement on what IARs sense. Some investigators believe the three types of sensors are actually one group with similar but different properties and IARs operate within that group. Other investigators (majority) believe IARs overlap with the RARs and...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 21, 2020 Category: Physiology Authors: Yu J Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Use of a carbonic anhydrase ca17a knockout to investigate mechanisms of ion uptake in zebrafish (Danio rerio).
In conclusion, while loss of Ca17a caused marked changes in ion uptake rates, providing strong evidence for a Ca17a-depedent Cl- uptake mechanism, the underlying causes of the lethality of this mutation in zebrafish remain unclear. PMID: 33085911 [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 - October 21, 2020 Category: Physiology Authors: Zimmer AM, Mandic M, Yew HM, Kunert E, Pan YK, Ha J, Kwong RWM, Gilmour KM, Perry SF Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Biokinetic Modeling of Nanoparticle Interactions with Lung Alveolar Epithelial Cells: Uptake, Intracellular Processing and Egress.
Abstract Studies on health effects of engineered nanomaterials (ENM) in the lung has provided information on ENM toxicity and translocation across airway and alveolar epithelial barriers. Various inhaled ENM (e.g., gold and iridium nanoparticles) have been reported to partially cross the air-blood barrier in the lung, enter the vasculature and distribute in several end organs including heart, liver, spleen and kidney. Using an in vitro primary rat alveolar epithelial cell (AEC) monolayer model, we reported transport rates of relatively non-toxic polystyrene nanoparticles (PNP), which appear to be taken up via non-...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 21, 2020 Category: Physiology Authors: Chen W, D'Argenio DZ, Sipos A, Kim KJ, Crandall ED Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Quantification of Body Fluid Compartmentalization by Combined Time-Domain Nuclear Magnetic Resonance and Bioimpedance Spectroscopy.
Abstract The measurement of fluid compartmentalization, or the distribution of fluid volume between extracellular (ECF) and intracellular (ICF) spaces, historically requires complicated, burdensome, and often terminal methodologies that do not permit repeated or longitudinal experiments. New technologies including time-domain nuclear magnetic resonance (TD-NMR)-based methods allow for highly accurate measurements of total body water (TBW) within minutes in a non-invasive manner, but do not permit dissection of ECF versus ICF reservoirs. In contrast, methods such as bioimpedance spectroscopy (BIS) allow dissection ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 21, 2020 Category: Physiology Authors: Segar JL, Balapattabi K, Reho JJ, Grobe CC, Burnett CML, Grobe JL Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

TRPV4 channel blockade does not modulate skin vasodilation and sweating during hyperthermia or cutaneous post-occlusive reactive and thermal hyperemia.
Abstract Transient receptor potential vanilloid 4 (TRPV4) channels exist on vascular endothelial cells and eccrine sweat gland secretory cells in human skin. Here, we assessed if TRPV4 channels contribute to cutaneous vasodilation and sweating during whole-body passive heat stress (protocol 1) and to cutaneous vasodilation during post-occlusive reactive hyperemia and local thermal hyperemia (protocol 2). Intradermal microdialysis was employed to locally deliver pharmacological agents to forearm skin sites where cutaneous vascular conductance (CVC) and sweat rate were assessed. In protocol 1 (twelve young adults), ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 21, 2020 Category: Physiology Authors: Fujii N, Kenny GP, McGarr GW, Amano T, Honda Y, Kondo N, Nishiyasu T Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

The independent and interactive effects of thermal stress and mental fatigue on manual dexterity.
Abstract Many occupations and sports require high levels of manual dexterity under thermal stress and mental fatigue. Yet, multi-stressor studies remain scarce. We quantified the interactive effects of thermal stress and mental fatigue on manual dexterity. Seven males (21.1±1.3y) underwent 6 separate 60-min trials characterised by a combination of 3 air temperatures (HOT: 37°C; NEUTRAL: 21°C; COLD: 7°C) and 2 mental fatigue states (MF: mental fatigue induced by a 35-min cognitive battery; No-MF: no mental fatigue). Participants performed complex (O'Connor test) and simple (Hand-Tool test) manual...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 14, 2020 Category: Physiology Authors: Valenza A, Charlier H, Bianco A, Filingeri D Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Hypertension is associated with blunted NO-mediated leg vasodilator responsiveness that is reversed by high-intensity training in postmenopausal women.
Abstract The menopausal transition is associated with increased prevalence of hypertension, and in time postmenopausal women (PMW) will exhibit a cardiovascular disease risk-score similar to male counterparts. Hypertension is associated with vascular dysfunction, but whether hypertensive PMW have blunted nitric-oxide (NO)-mediated leg vasodilator responsiveness, and whether this is reversible by high-intensity training (HIT) is unknown. To address these questions, we examined the leg vascular conductance (LVC) in response to femoral-infusion of acetylcholine (ACh) and sodium nitroprusside (SNP), and skeletal muscl...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 14, 2020 Category: Physiology Authors: Gunnarsson TP, Ehlers TS, Baasch-Skytte T, Lund AP, Tamariz-Ellemann A, Gliemann L, Nyberg M, Bangsbo J Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

The effects of antenatal dexamethasone and hyperglycemia on cardiovascular adaptation to asphyxia in preterm fetal sheep.
In this study, preterm fetal sheep received either saline or 12 mg i.m. maternal dexamethasone, followed 4 h later by complete umbilical cord occlusion (UCO) for 25 min. An additional cohort of fetuses received titrated glucose infusions followed 4 h later by UCO, to control for the possibility that hyperglycemia contributed to the cardiovascular effects of dexamethasone. Fetuses were studied for 7 d after UCO. Maternal dexamethasone was associated with fetal hyperglycemia (p
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 14, 2020 Category: Physiology Authors: Lear CA, Davidson JO, Dhillon SK, King VJ, Lear BA, Magawa S, Maeda Y, Ikeda T, Gunn AJ, Bennet L Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Renal functional reserve: From physiological phenomenon to clinical biomarker and beyond.
Abstract Glomerular filtration rate (GFR) is acutely increased following a high protein meal or systemic infusion of amino acids. The mechanisms underlying this renal functional response remain to be fully elucidated. Nevertheless, they appear to culminate in pre-glomerular vasodilation. Inhibition of the tubuloglomerular feedback signal appears critical. However, nitric oxide, vasodilator prostaglandins, and glucagon also appear important. The increase in GFR during amino acid infusion reveals a 'renal reserve' which can be utilized when the physiological demand for single nephron GFR increases. This has led to t...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 14, 2020 Category: Physiology Authors: Jufar AH, Lankadeva YR, May CN, Cochrane AD, Bellomo R, Evans RG Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research

Effect of Endoplasmic Reticulum Stress on Endothelial Ischemia-Reperfusion Injury in Humans.
Abstract Endoplasmic reticulum stress contributes to ischemia-reperfusion (I/R) injury in rodent and cell models. However, the contribution of endoplasmic reticulum stress in the pathogenesis of endothelial I/R injury in humans is unknown. We tested the hypothesis that compared with placebo, inhibition of endoplasmic reticulum stress via ingestion of tauroursodeoxycholic acid would prevent the attenuation of endothelium-dependent vasodilation following I/R injury. Twelve young adults (six women) were studied following ingestion of a placebo or 1,500 mg tauroursodeoxycholic acid (TUDCA). Endothelium-dependent vasod...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - October 14, 2020 Category: Physiology Authors: Hemingway HW, Moore AM, Olivencia-Yurvati AH, Romero SA Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research