bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal effect induced by anandamide is dissociated of locomotor and feeding behavior (1105.5)
Authors: Lima Paulo , Machado Frederico , Coimbra Cândido 
Published: June 2021

The endocannabinoid system has an important role on thermal control and modulates behaviors that may affect the body temperature (Tb), such as locomotion and food intake (FI). In order to test whether changes on Tb induced by anandamide (AEA) are related with behavioral changes, rats received an i.c.v. injection of AEA (0.1, 1.0 and 10.0 μg) and vehicle. Total FI was daily weighted, and both Tb and spontaneous locomotor activity (SLA) were simultaneous and continuously recorded. AEA induced increase on Tb without changes on SLA and FI. For all doses tested, the Tb average at post‐injection period was higher than pre‐injection period. Higher termal effect was verified by 10.0 μg of AEA, starting within the first hour post‐injection, being maintained for 8 hours after treatment. At the first hour, a dose‐dependent thermal effect was observed (r = 0.953; p<0.05). Hypoactivity was verified only for 1.0 μg of AEA. As expected, both Tb and SLA values at dark phase were always higher than at light phase with a positive correlation between them (r = 0.834, p<0.001), however this correlation was inverted (r = ‐0.852, p<0.01) after 10.0 μg of AEA. In summary, our results suggest that brain AEA induces increase of Tb, and this effect may occur independently of changes in both locomotion and FI. Moreover, it is possible that hypolocomotion induced by AEA could be an adaptive response due to increased Tb.Grant Funding Source: CNPQ, Capes and Fapemig
Aging is associated with slowed vasodilator kinetics in dynamically contracting muscle: role of nitric oxide (1106.10)
Authors: Casey Darren , Walker Branton , Ranadive Sushant , Joyner Michael 
Published: June 2021

We tested the hypothesis that aging would be associated with slowed vasodilator kinetics in contracting muscle in part due to a reduced nitric oxide (NO) bioavailability. Young (n=10; 24 ± 2 yr) and older (n=10; 67 ± 2 yr) adults performed rhythmic forearm exercise (4 min each) at 10, 20 and 30% of max during saline infusion (control) and NO synthase (NOS) inhibition. Brachial artery diameter and velocities were measured using Doppler ultrasound. Forearm vascular conductance (FVC) was calculated for each duty cycle (1s contraction/2s relaxation) from blood flow (ml/min) and blood pressure (mmHg) and fit with a monoexponential model. The main parameters derived from the model were the amplitude (Amp) of the FVC response and the number of duty cycles for FVC to change 63% of the steady‐state amplitude (τFVC). Under control conditions 1) the Amp of the response at 20 and 30% MVC was lower in older (240 ± 24 and 319 ± 33 ml/min/100mmHg) compared to young adults (338 ± 45 and 462 ± 52 ml/min/100mmHg; P < 0.05) and 2) τFVC was slower in older (10 ± 1, 13 ± 1 and 15 ± 1 duty cycles) compared to young (6 ± 1, 9 ± 1 and 11 ± 1 duty cycles) adults at all intensities (P < 0.05). NOS inhibition blunted the Amp and slowed the τFVC in young, at all intensities (10 ± 2, 12 ± 1 and 16 ± 2 duty cycles; P < 0.05), whereas it did not change in older adults. Our data indicate that the vasodilator kinetics in exercising muscle are altered with aging likely due to blunted NO signaling.Grant Funding Source: Supported by NIH grants HL105467 (DPC), HL46493 (MJJ) and by CTSA UL1 TR000135
Involvement of NAD(P)H oxidase in acrolein‐induced oxidative stress (1106.14)
Authors: Yousefipour Zivar , Newaz Mohammad 
Published: June 2021

Acrolein toxicity has been linked to oxidative stress & inflammation. NAD(P)H oxidase plays an important role in oxidative stress. gp91phox, an essential component of NAD(P)H oxidase, maintains the functionality of the enzyme. The precise contribution of NAD(P)H in acrolein‐induced toxicity is not fully explored. We investigated the involvement of NAD(P)H oxidase in acrolein toxicity using gp91phox knock‐out (KO) mice. Male gp91 KO mice (20‐25 g) or wild type (WT) control were treated with acrolein (0.5 μg/kg; 1 week). Animals were sacrificed and liver was used for biochemical analysis. KO mice generated low (1.43±.02 pg/μg protein) free radical as evident by 8‐Isoprostane compare to the WT mice (2.19±0.1). Acrolein increased 8‐Isoprostane in WT (P<0.05) but not in KO mice. Xanthine Oxidase (XO) activity was higher (p<0.05) in KO (0.56±0.06 μunit/μg protein). Acrolein reduced XO in KO mice while significantly increased it in WT. Cycloxygenase (COX) activity was not different between WT and KO mice although acrolein increased COX in WT. KO mice exhibited a significantly low (2.1±0.2 μmol/mg protein) total antioxidant status (TAS) compared to the WT (3.5±0.3). Acrolein reduced TAS in both WT and KO mice in an equal manner. These data suggests that NAD(P)H oxidase contributes significantly in acrolein‐induced oxidative stress. We suggests that in absence of NAD(P)H oxidase XO and COX play a definitive role in this process. We also suggest that besides generating free radical, acrolein reduces antioxidant ability thus compounding the effects of oxidative stress.Grant Funding Source: Supported by NIH‐SC3
Tempol improves cutaneous thermal hyperemia through increasing nitric oxide bioavailability in young smokers (1106.2)
Authors: Fujii Naoto , Brunt Vienna , Francisco Michael , Minson Christopher 
Published: June 2021

We recently found that young cigarette smokers display cutaneous vascular dysfunction relative to non‐smokers, which is partially due to reduced nitric oxide (NO) synthase (NOS)‐dependent vasodilation. In this study, we tested the hypothesis that reducing oxidative stress improves NO bioavailability, enhancing cutaneous vascular function in young smokers. In ten healthy young male smokers, cutaneous vascular conductance (CVC) during local heating to 42ºC at a rate of 0.1ºC/sec was evaluated as laser‐Doppler flux divided by mean arterial blood pressure. We evaluated plateau CVC during local heating, which is known to be highly dependent on NO, at four intradermal microdialysis sites: 1) Ringer’s (control), 2) 10μM 4‐hydroxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl (Tempol), a superoxide dismutase mimetic, 3) 10mM Nω‐Nitro‐L‐arginine (L‐NNA), a non‐specific NOS inhibitor, and 4) a combination of 10μM Tempol and 10mM L‐NNA. Tempol increased the plateau CVC compared with the Ringer’s site (90.0±2.3 vs. 77.6±3.9%max, P=0.049). Plateau CVC at the combination site (56.8±4.5%max) was lower than the Ringer’s site P=0.002), and was not different from the L‐NNA site (55.1±4.6%max) (P=0.778), indicating the Tempol effect was exclusively NO‐dependent.These data suggest that in young smokers, reducing oxidative stress improves cutaneous thermal hyperemia to local heating by enhancing NO production.Grant Funding Source: This study is supported by NIH HL081671 and The Uehara Memorial Foundation
Sex differences observed in forearm exercise vasodilation are not mediated through differences in nitric oxide or prostaglandin signaling (1106.3)
Authors: Kellawan Jeremy , Johansson Rebecca , Harrell John , Trierweiler Joshua , Crain Meghan , Sebranek Joshua , Walker Benjamin , Eldridge Marlowe , Schrage William 
Published: June 2021

We hypothesized exercise vasodilation in skeletal muscle differs between sexes due to nitric oxide synthase (NOS) and cyclooxygenase (COX) signalling. 39 healthy adults (19 females, F, 20 males, M, 26 ± 1 yrs) completed two 10‐min bouts of dynamic forearm exercise at 15% effort, separated by 20 min rest. After 5 min of control exercise, NOS or COX was inhibited during the final 5 min of exercise by intra‐arterial infusion of L‐NMMA or ketorolac, respectively. During min 5‐10 of the second exercise bout the remaining drug was infused to achieve double blockade (DB). Forearm blood flow (FBF; echo and Doppler ultrasound), arterial pressure (brachial catheter), and forearm lean mass (DEXA) were measured to calculate relative forearm vascular conductance (FVC) = FBF/100mmHg/100g lean mass. Results are mean ± SE. Females exhibited greater vasodilation than Males in control exercise (Δ FVC, 19±1 vs. 14±1, P < 0.01). L‐NMMA reduced FVC similarly (F: Δ ‐2.3 ± 1.3 vs. M: Δ – 3.7 ± 0.8, p = 0.85). In contrast, ketorolac increased FVC similarly in Females and Males (F: Δ 2.1 ± 1.3 vs. M: Δ 2.2± 1.9, p = 0.83). Despite Females exhibiting a greater exercise FVC, DB caused similar Δ FVC between the sexes (0.89). Females have a greater exercise vasodilatory response. NOS, COX, and DB responses are similar, thus, exercise vasodilation differences between sexes are due to a NOS‐COX independent mechanism(s).Grant Funding Source: Supported by NIH 144PRJ52FK
Cholecystokinin activates a Ca2+‐dependent Cl‐ conductance in intestinal nodose neurons that is inhibited in diet‐induced obesity and may suppress satiety (1107.8)
Authors: Wang Runping , Lu Yongjun , Cicha Michael , Rahmouni Kamal , Chapleau Mark , Benson Christopher , Abboud Francois 
Published: June 2021

The cholecystokinin (CCK) induced satiety signaling of vagal afferents is suppressed in diet‐induced obese mice, which contributes to the increased food intake. In this study we tested the hypothesis that a Ca2+‐activated chloride channel (CaCC) mediates the response of normal intestinal vagal afferent nodose neurons to CCK and that excessively high fat diet (HFD) suppresses the channel activation and leads to obesity. We first used Ca2+ imaging techniques and the whole cell patch‐clamp on cultured nodose ganglia neurons isolated from anesthetized C57/BL6 mice. Application of CCK increased [Ca2+]i in a dose‐dependent manner reaching near maximal level at 10 μM. This dose of CCK also induced a large inward current (36.0±11.0 pA/pF, n=7) that was eliminated with the fast Ca2+ chelator BAPTA (1.0±0.5 pA/pF, n=7). The reversal potential of the current was ~0mV with equal concentration of Cl‐ on both sides of the cell membrane and shifted to a more positive direction after lowering the extracellular [Cl‐]o confirming that it is an outward Cl‐ conductance. Moreover, the CCK‐induced response was reduced significantly from 35.2±3.2 pA/pF in untreated control neurons (n=9) to 13.6±2.0 pA/pF in the presence of niflumic acid (100μM, n=8), a blocker of the CaCC channel (p<0.05). DiI labeled proximal intestinal nodose neurons obtained from control mice responded to CCK with an average current of 24.8±4.9 pA/pF (n=7), whereas the response of labeled neurons from obese mice fed a 60% HFD for 10 weeks was significantly lower at 6.1±2.9 pA/pF (n=7) (p<0.01). Our results demonstrate that a CCK‐sensitive CaCC in proximal intestinal nodose neurons is desensitized in mice fed a high fat diet. This CaCC ionic conductance may be responsible for satiety signaling of vagal afferents and its impairment may contribute to excessive food intake and obesity.Grant Funding Source: Supported by NIH HL 14388
Multivalent cell specific therapeutics for treatment of metabolic disorders (1108.1)
Authors: Lynch Ron , Weber Craig , Hart Nathaniel , Limesand Sean , Xu LiPing , Morse David , Gillies Robert , Vagner Josef 
Published: June 2021

Metabolic Homeostasis is mediated via multi‐organ endocrine signaling. Because many systems are involved, therapeutics often have wide‐ranging side‐effects. We have shown therapeutic specificity can be achieved with agents that simultaneously bind two different receptors that, as a combination, are relatively unique to a given cell type. Bivalent ligands, that target cells within the homeostatic axis, were produced; melanocyte stimulating hormone linked to CCK (MSH/CCK), and Glucagon Like Peptide 1 (GLP‐1) linked to Glibenclamide (Glb, SUR1 antagonist). Binding analyses, assessed with cells expressing the complementary receptor pair, indicate an apparent Kd of ~5 nM for MSH/CCK, ~10nM for GLP‐1/Glb. Constants for the individual domains within the bivalent constructs were 30 nM or greater, and neither ligand bound with high affinity to cells expressing only one of the complementary receptors, indicating that high affinity binding requires both receptors. Once bound, the ligand/ receptor complex is rapidly endocytosed. Both ligands maintain signaling capacity, though the magnitude, sensitivity of 2nd messenger and physiological effects, differ from the constituent monomers. Uniquely, GLP‐1/Glb was found to potentiate insulin secretion at stimulatory glucose concentrations, but inhibit, rather than activate, at non‐stimulatory glucose. Thus, these bivalent ligands exhibit enhanced affinity, cell type specificity and maintain functional efficacy, and thereby hold promise as cell specific therapeutic agents.Grant Funding Source: Supported by: Juvenile Diabetes Research Foundation, National Institutes of Health, NCI, CA123547
Chronic blockade of the renin‐angiotensin system improves glucose metabolism and pancreatic superoxide dismutase activity in insulin resistant rats (1108.12)
Authors: Rodriguez Ruben , Minas Jacqui , Vazquez‐Medina Jose , Nakano Daisuke , Nishiyama Akira , Ortiz Rudy 
Published: June 2021

Blockade of the renin‐angiotensin‐system (RAS) improves pancreatic function, decreases fasting blood glucose (FBG), glucose intolerance, insulin resistance (IR) and delays the onset of type 2 diabetes. However, the timing of the onset of the beneficial effects of RAS blockade is not clear. To assess the timing of the beneficial effects of RAS blockade, we measured fasting blood glucose, glucose intolerance, insulin resistance index (IRI) and pancreatic antioxidant activity after 2 and 11 weeks of angiotensin receptor blocker (ARB) treatment in the following groups of rats: 1) LETO (lean strain‐control), 2) untreated fatty obese‐OLETF, 3) OLETF + ARB (ARB; 10 mg olmesartan/kg/d). OLETF rats exhibited elevated FBG, glucose intolerance and IRI at 9 weeks of age compared to LETO and they worsen with age. Two week treatment with ARB did not decrease FBG, glucose intolerance or IRI, whereas 11 week treatment decreased them by 23%, 26% and 47%, respectively, compared to OLETF. OLETF rats also exhibited decreased pancreatic antioxidant enzyme activity as compared to LETO. Two week treatment with ARB did not increase antioxidant enzyme activity; however, 11 week‐treatment increased 42% superoxide dismutase activity compared to OLETF. These data suggest that the beneficial effects that RAS blockade have on glucose metabolism and pancreatic antioxidant activity are not immediate, but improve with treatment duration.Grant Funding Source: Supported by NIH NCMHD 9T37MD001480.
Shedding of ACE2 by mature form of ADAM17 is mediated by angiotensin type 1 receptor (1108.14)
Authors: Chodavarapu Harshita , Chhabra Kavaljit , Pedersen Kim , Lazartigues Eric 
Published: June 2021

ADAM17 (a disintegrin and metalloprotease) is associated with shedding of ACE2 in diabetic rodent models with overactive Renin‐Angiotensin System. To test the role of ADAM17 in pancreatic ACE2 shedding, C57Bl/6J mice (n=5/group) were fed high fat diet (HFD) for 16 weeks. HFD fed mice showed hyperglycemia (HFD: 150 ±10.7 vs. Control: 103 ±3.6 mg/dl P<0.05) and glucose intolerance (HFD: 43438 ±2803 vs. Control: 35903 ±2075 AU P<0.05). Western blot and Quantitative RT‐PCR showed 2 fold increase in both pancreatic ADAM17 protein and mRNA expression (p<0.05) in HFD mice. This was associated with a 1.5 fold reduction (p<0.05) in pancreatic ACE2 protein and 1.5 fold increase (p<0.05) in mRNA expression in HFD mice. To directly implicate the role of Angiotensin (Ang) II type 1 receptor (AT1R) in ADAM17 expression, an immortalized human pancreatic beta cell line (β‐lox 5) was used. Treatment with 500 nM Ang II resulted in 2 fold increase (p<0.05) in ADAM17 protein expression which was attenuated by losartan (AT1R blocker). Further, transfection of β‐lox 5 cells with hACE2/pcDNA3.1 followed by treatment with an ADAM17 overexpressing adenovirus resulted in 2 fold increase in the pro form (p<0.05) but not the mature form of ADAM17 protein expression and no change in hACE2 expression. In conclusion, our results demonstrate that AT1R‐mediated increase in the mature form of ADAM17 is responsible for the shedding of pancreatic ACE2.Grant Funding Source: Supported by American Heart Association (110300120A)
Fructose stimulates phosphorylation and trafficking of the Na/K/2Cl cotransporter in rat thick ascending limbs (1109.2)
Authors: Ares Gustavo , Kassem Kamal , Ortiz Pablo 
Published: June 2021

High fructose consumption affects renal salt handling and is linked to salt‐sensitive hypertension in humans and rodents. The thick ascending limb (TAL) reabsorbs 25% of filtered NaCl via NKCC2. However, the effect of fructose on NKCC2 and TAL NaCl absorption is unknown. We hypothesized that acute and chronic fructose treatment stimulate NKCC2 activity and trafficking in TALs. Acute fructose treatment (20 min) enhanced surface NKCC2 expression (Fructose 1mM= 22 ± 5%, 5mM= 49 ± 10%, 10mM= 101 ± 59%; p<0.05), but did not increase NKCC2 phosphorylation at Ser126, Thre96/101, nor total NKCC2 expression. Fructose (5mM) increased NaCl transport‐related TAL oxygen consumption by 11 ± 3% (p<0.05), and this effect was absent when NKCC2 was blocked by furosemide. In contrast, glucose (5 mM) did not affect surface NKCC2 nor TAL oxygen consumption. When Sprague‐Dawley rats were fed 20% fructose for 1 week, surface‐to‐intracellular NKCC2 increased by 61 ± 23% (p<0.05), Thre96,101 phosphorylation increased by 8 ± 3 fold (p<0.05) but total NKCC2 expression was reduced by 40 ± 9% (p<0.05). We concluded that acute fructose treatment increases surface NKCC2 expression and NaCl transport by TALs. One week on a fructose enriched diet increased NKCC2 trafficking and phosphorylation at Thre96/101. Our data suggest that fructose but not glucose may contribute to salt‐sensitive hypertension by stimulating NKCC2 and NaCl absorption.Grant Funding Source: 1P01HL090550
Regulation of NCC and the WNK cascade by the circadian clock protein Per1 in murine distal convoluted tubule cells (1109.5)
Authors: Richards Jacob , Ko Benjamin , All Sean , Cheng Kit‐Yan , Hoover Robert , Gumz Michelle 
Published: June 2021

Blood pressure and renal function undergo circadian fluctuations. We have shown that the circadian protein Per1 regulates genes involved in sodium (Na) transport in the kidney collecting duct, but has not been investigated in other parts of the nephron. The distal convoluted tubule (DCT) plays a critical role in Na reabsorption in the nephron through the actions of the Na‐Cl co‐transporter (NCC), which is regulated by the with‐no‐lysine kinases (WNKs). Therefore, we wanted to test the hypothesis that Per1 regulates Na transport in the DCT through modulation of NCC, WNK1 and WNK4.Pharmacological blockade of nuclear Per1 entry resulted in decreased mRNA expression of NCC and WNK1, but increased expression of WNK4 in mouse renal cortex. These findings were confirmed by Per1 siRNA and pharmacological blockade of Per1 nuclear entry in mDCT15 cells, a model of the mouse distal convoluted tubule. Measurement of short‐lived hnRNA demonstrated that the effect of Per1 was transcriptional. Chromatin immunoprecipitation experiments demonstrated interaction of Per1 and CLOCK with the promoters of NCC, WNK1, and WNK4; blockade of Per1 nuclear entry abolished these effects. Importantly, NCC activity, as measured by thiazide‐sensitive, Cl‐dependent 22Na uptake, was decreased upon pharmacological inhibition of Per1 nuclear entry. These data demonstrate a role for Per1 in the transcriptional regulation of NCC, WNK1, and WNK4.Grant Funding Source: Supported by NIH, ASN and AHA
Activation of the AT1 receptor‐beta‐arrestin signaling pathway inhibits NHE3 activity in the renal proximal tubule (1109.8)
Authors: Carneiro de Morais Carla , Oliveira‐Souza Maria , Pessoa Thaissa , Malnic Gerhard , Krieger Jose , Girardi Adriana 
Published: June 2021

Previous studies have demonstrated that TRV120023, a novel biased peptide ligand of the angiotensin II type 1 receptor (AT1) which specifically activates the beta‐arrestin mediated signaling pathway, exerts diuretic and natriuretic actions. The present study tested the hypothesis that TRV120023 inhibits NHE3 activity in rat renal proximal tubules (PT) and in a PT cell line (OKP cells). PT NHE3 activity was measured as the rate of bicarbonate reabsorption by in vivo stationary microperfusion whereas Na+‐dependent pHi recovery after an acid load was employed to evaluate NHE3‐mediated H+ extrusion in OKP cells. TRV120023 (10‐7M) significantly inhibited net proximal tubule bicarbonate reabsorption (2.00 ± 0.31 vs. 1.39 ± 0.22 nmol/cm2/s (P <0.001). In OKP cells, Na+‐dependent pH recovery was reduced by TRV120023 in a dose dependent manner. Moreover, experiments performed in the presence of the NHE3 inhibitor S3226 demonstrated that the inhibitory effect on NHE3‐mediated Na+‐dependent intracellular pH recovery decreased approximately 50% after 30 minute‐treatment with TRV120023 (0.18 ± 0.03 vs. 0.09 ± 0.03 pH units/min, P<0.001). The inhibitory effect of TRV120023 on NHE3 activity in OKP cells was blocked by wortmannin, a phosphatidylinositol‐3‐kinase (PI3K) inhibitor but not by the ERK inhibitor U0126. Taken together our results suggest that the diuretic and natriuretic effects of TRV120023 may be, at least in part, due to renal proximal tubule NHE3 inhibition via activation of the AT1R/beta‐arrestin/PI3K signaling pathway.Grant Funding Source: FAPESP
Vagally‐mediated gastric effects of catecholamines in stressed rats (1110.13)
Authors: Browning Kirsteen , Fries Allison , Travagli R. Alberto 
Published: June 2021

Stress exerts vagally‐mediated action to disrupt gastric motility. Preliminary results from our laboratory suggest that brainstem vagal neurocircuits undergo remodeling following stress and previous studies from other groups have shown that the A2 catecholaminergic area is involved in these effects.The aim of this study was to investigate whether stress modulates the response of vagally‐mediated gastric pathways to catecholamines.Inhibitory postsynaptic currents (IPSCs) were recorded in neurons of the dorsal motor nucleus of the vagus (DMV) following NTS stimulation and perfusion of the slices with the α2 agonist Uk14304 (0.1‐10μM). In control rats, UK14304 had no effect on 5 of 5 neurons tested (96±3% of baseline amplitude); in contrast, UK14304 decreased the amplitude of IPSC in 12 of 17 rats that underwent homotypic stress for 5 days in a concentration‐dependent manner (91±1%, 78±1% and 53±9% of baseline amplitude in response to 0.1, 1 and 3μM, respectively; P<0.05 vs control). In control rats, brainstem microinjections of the indirect sympathomimetic tyramine (4.5nmoles/60nl) reduced gastric motility to 50±10% of baseline (N=10); conversely, microinjections of tyramine in the brainstem of homotypic stress rats decreased gastric motility to 7±5% of baseline (N=2).These data suggest that homotypic stress induces an upregulation of catecholaminergic, including α2‐mediated, responses in vagal neurocircuits resulting in an exaggerated vagally‐mediated gastroinhibition.Grant Funding Source: NIH DK55530, DK78364