bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low Dose Mephedrone Depicts a Combined Dopaminergic and Serotonergic Discriminative Stimulus Effect
Authors: Saber Iman , Ward Sara Jane , Rawls Scott , Walker Ellen 
Published: June 2021

Mephedrone (MEPH) is a recreational synthetic cathinone and a major component of psychoactive 'bath salts.' In previous studies, MEPH increases dopamine (DA) and serotonin (5‐HT) release and inhibits DA and 5‐HT synaptosomal uptake. A previous assay used a high dose MEPH to establish a discriminative stimulus and found 5‐HT stimulants to fully substitute for MEPH (Varner et al., Psychopharmacology 225:675, 2013). The purpose of this experiment was to pharmacologically profile MEPH using a very low training dose in a drug discrimination procedure. Sprague‐Dawley rats were trained using a two‐choice drug discrimination assay to examine the properties of 0.5 mg/kg MEPH. We hypothesized that MEPH would produce discriminative stimulus effects based upon multiple component cues of DA and/or 5‐HT, and therefore these cues would be blocked by DA and/or 5‐HT antagonists. When tested, the DA agonists cocaine, methamphetamine, and d‐amphetamine produced 23, 99, and 77 % MEPH‐like responding while 5‐HT agonists meta‐chlorophenylpiperazine (mCPP) and 3, 4‐methylenedioxymethamphetamine (MDMA) produced 64 and 97 % MEPH‐like responding, respectively. The DA1 receptor antagonist SCH23390 produced a reduction in MEPH discriminative stimulus effects while the 5‐HT2C receptor antagonist SB242084 completely reversed the effects of the training dose of MEPH. The DA2 antagonist sulpiride produced increased rate‐decreasing effects in combination with MEPH. In conclusion, a very low dose of MEPH was established as a discriminative stimulus and it appears the composite pharmacological profile is a unique composition of DA and 5‐HT activation.R21 DA032718
Substrate‐Dependent Inhibition of Human Renal Organic Cation Transporter 2 (OCT2) by Cimetidine
Authors: YIN JIA , Duan Haichuan , Isoherranen Nina , Wang Joanne 
Published: June 2021

Inhibition of transporter‐mediated renal drug secretion is a significant concern for clinical drug‐drug interactions (DDIs). In the recent draft FDA guidance for drug interaction studies, metformin and cimetidine were respectively suggested as the model substrate and inhibitor for in vivo DDI assessment for OCT2, a major renal transporter responsible for tubular secretion of cationic drugs. Emerging evidence suggests that the inhibition potency of a specific compound towards OCT2 is substrate‐dependent, but the available data was mostly obtained with experimental compounds that are not used clinically. The aim of this study was to determine whether cimetidine inhibition of OCT2 differs towards metformin and atenolol, two clinically used drugs predominantly eliminated by the kidney. The IC50 values and mechanism of inhibition were determined by transport assays in Flp‐In 293 cells stably expressing human OCT2. The IC50 values of cimetidine towards OCT2‐mediated metformin and atenolol transport were 93.5 ± 1.1 μM, and 9.9 ± 1.1 μM respectively. Detailed kinetics analysis further revealed a mixed inhibition model for both substrate drugs. The Ki values based on mixed inhibition model differed more than 70 fold for metformin and atenolol. The data suggest that with a Cmax value of 8 ~ 12 μM, cimetidine will significantly inhibit OCT2‐mediated atenolol renal secretion in vivo without affecting OCT2‐mediated metformin transport. Therefore, data obtained from one probe substrate may not be applicable to other drug substrates in assessing DDI potentials for OCT2.This study was supported by the NIH grants R01GM066233 and TL1 TR000422.
Identification of Type I Interferon as a Novel Therapeutic Approach for Targeting Alveolar Rhabdomyosarcoma
Authors: Nieves Kiomaris , Henrich Ian , Young Robert , Quick Laura , Bledsoe Krista , Chou Margaret 
Published: June 2021

Bone and soft tissue tumors (BSTT) are a group of neoplasms most commonly found in children. The TRE17/ ubiquitin‐specific protease 6 (USP6) oncogene is intimately involved in several BSTTs, including alveolar rhabdomyosarcoma (ARMS). The molecular functions of TRE17 in ARMS pathogenesis are unknown. However, recent unpublished data from our lab has identified the Jak1‐STAT1/3 pathway as a key effector of TRE17.Type I Interferon (IFN) has been used previously to treat sarcomas. IFN functions through Jak1/STAT1. Interestingly, we found that TRE17 renders ARMS hypersensitive to IFN‐induced apoptosis in vitro. TRE17‐expressing ARMS, but not control ARMS, underwent apoptosis after 24h of IFN treatment. In addition to inducing apoptosis, IFN also resulted in the degradation of TRE17. The exact mechanisms behind the sensitization and subsequent downregulation of TRE17 in ARMS remain to be uncovered. The degradation of TRE17 appears to require its ubiquitin‐specific protease activity. Currently, work is being done to find the mechanism of TRE17 degradation upon exposure to IFN; preliminary data suggest that the proteosomal pathway is responsible. These studies may identify methods to sustain or induce TRE17 expression, which would render ARMS susceptible to killing by IFN, and ultimately allow exploration of IFN as a therapeutic agent for ARMS treatment.
Stress Responses Initiated in Cardiomyocytes during Hypothermia‐Induced Rewarming Shock
Authors: Schaible Niccole , Han Young Soo , Zaidan Louai , Arteaga Grace , Tveita Torkjel , Sieck Gary 
Published: June 2021

Rewarming shock following accidental hypothermia is a potentially fatal scenario involving cardiac dysfunction. Previously our lab demonstrated that rewarming shock results in a decrease in Ca2+ sensitivity of contraction in cardiac muscle due to an increase in cTnI phosphorylation. In this study, we hypothesized that rewarming shock initiates a cascade of intracellular events including reactive oxygen species (ROS) formation, endoplasmic reticulum (ER) stress, and mitochondrial disruption. Isolated cardiomyocytes from Sprague‐Dawley rats were exposed to a hypothermia/rewarming protocol (cooled for 1 h, held at 17oC for 30 min, rewarmed for 1 h) that results in contractile dysfunction indicated by an increase in cytosolic Ca2+ and reduced cell shortening measured using an IonOptix system. Rewarming shock increased ROS levels measured by an HPLC‐based dihydroethidium assay and by MitoSox fluorescence. Hypothermia/rewarming was also associated with ER stress indicated by increased expression of ER stress markers (Grp78, PERK, and CHOP) measured by Western blot. Finally, rewarming shock was associated with mitochondrial disruption evidenced by mitochondrial membrane depolarization (decreased in TMRM fluorescence) and by an increase in cytosolic cytochrome c (measured by Western blot). Our results support our overall hypothesis and suggest that these ER and mitochondrial intracellular events may underlie myocardial contractile dysfunction following hypothermia/rewarming.Supported by NIH Grant 5T32HL105355‐02 (GCS)
Alpha 2‐Adrenergic Receptor Modulation of Calcium Current is Impaired in Mesenteric Artery Projecting Sympathetic Neurons in DOCA‐Salt Hypertensive Rats
Authors: Mui Ryan , Fernandes Roxanne , Galligan James 
Published: June 2021

In sympathetic neurons, activation of the prejunctional alpha 2‐adrenergic receptor (a2‐AR) inhibits nerve terminal N‐type Ca2+ channels and norepinephrine (NE) release onto blood vessels. In rats, a2‐AR dysfunction contributes to DOCA‐salt hypertension; however, the mechanism responsible for a2‐AR dysfunction is unknown. We tested the hypothesis that a2‐AR coupling to inhibition of N‐type Ca2+ channels is disrupted in DOCA‐salt hypertension.MethodsWe used cholera toxin (CTx)‐conjugated Alexafluor 588 to retrogradely label mesenteric artery projecting sympathetic neurons of the celiac ganglion (CG). We used whole‐cell patch clamp to study Ca2+ currents in these neurons. RT‐PCR and immunohistochemistry were used to evaluate a2‐AR subtype expression in CG neurons.ResultsCa2+ current amplitudes were similar in neurons from normotensive and DOCA‐salt hypertensive rats. The a2‐AR agonists NE and UK14304 decreased calcium currents to a greater degree in normotensive rats than in DOCA‐salt hypertensive rats. The a2‐AR antagonist yohimbine blocked inhibition of Ca2+ currents caused by NE in all neurons. Immunohistochemistry revealed that CG sympathetic neurons express predominantly a2‐AR subtypes 2A and 2C. RT‐PCR revealed that gene expression levels of a2‐AR subtype 2A are comparable in normotensive and DOCA‐salt hypertensive rats.ConclusionsIn DOCA‐salt sensitive hypertension, a2‐AR dysfunction results in impaired modulation of Ca2+ calcium current. This is not due to down regulation of the a2‐AR. Supported by NIH (P01 HL070687).
β3‐ Adrenergic Receptor Activation and Endoplasmic Reticulum Stress via Modulation of Intracellular Free Zn2+in Hyperglycemic Cardiomyocytes
Authors: Turan Belma , Tuncay Erkan , Toy Aysegul , Cicek Figen 
Published: June 2021

Beta‐adrenergic receptor (β‐AR)‐signaling plays important role in normal cardiac function while β3‐AR activation depresses cardiac contractile force. Since intracellular free Zn2+releases are originated either from metallothionin‐nitrolisation or endoplasmic reticulum (ER) and disturbing excitation‐contraction cyclying in cardiomyocytes, we examined role of β3‐AR activation on modulation of intracellular free Zn2+and ER stress (ERS) in hyperglycemic cardiomyocytes. Protein and mRNA levels of β3‐AR were increased in diabetic cardiomyocytes being associated with depressed left ventricular developed pressure. β3‐AR stimulation with BRL37344 induced significant increase in intracellular free Zn2+in diabetic cardiomyocytes which was diminished either with NOS inhibitor L‐NAME or β3‐AR antagonist SR59230 while it was further increased with non‐selective β‐blocker nadolol. Additionally, either BRL37344 or NO‐donor SNP induced significant increases in intracellular free Zn2+in normal cardiomyocytes while they were diminished either with L‐NAME or ODQ. These data are strongly demonstrated an association between increased intracellular free Zn2+ and β3‐AR activation in diabetic cardiomyocytes. BRL37344 stimulation of only diabetic cardiomyocytes presented also marked increases in ERS‐associated proteins which are very similar to those of diabetics. Taken together, our data demonstrated that β3‐AR activation in cardiomyocytes under hyperglycemia induces marked increase in intracellular free Zn2+which seems to be closely related with ERS, thereby both actions can underlie the depressed cardiac function in diabetics.(Supported by TUBITAK‐SBAG‐113S466)
Acute IP Phlorizin Normalizes Cortical PO2 But Causes Medullary Hypoxia in The Diabetic Rat Kidney
Authors: O Neill Julie , Patinha Daniela , Fasching Angelica , Pihl Liselotte , Franzen Stephanie , Palm Fredrik 
Published: June 2021

Diabetic nephropathy is characterized by glomerular hyperfiltration and reduced renal cortical oxygen tension (CPO2). Recent, observations indicate that increased tubular sodium glucose linked transport (SGLT) plays a role in the development of hyperfiltration in diabetic mice (Sällstrom et al 2014). The aim of the current study was to determine how inhibition of SGLT impacts upon renal tissue PO2 in the diabetic rat kidney.Diabetes was induced by intraperitoneal (IP) STZ (50mg/kg) injection in Sprague Dawley rats (n=9), 2 weeks prior to experimentation. Animals were surgically prepared for intravenous infusion of [3H]Inulin and [14C]PAH, the IP delivery of Phlorizin (sodium‐glucose transport inhibitor; 200mg/Kg) and the measurement of mean arterial pressure (MAP), left kidney function, CPO2 and medullary (M) PO2 (Clark electrode). Data± SEM was analyzed using a two‐way RM ANOVA. Baseline MAP, urinary glucose excretion (UGE) fractional sodium excretion (FENa), CPO2 and MPO2 was 118±2 mmHg, 0.26±0.07 mg/min, 0.09±0.03%, 36±1 mmHg and 27±2 mmHg respectively. IP Phlorizin had no effect on MAP but significantly increased UGE, FENa and CPO2 to 0.6±0.2 mg/min, 0.6±0.1 % and 49±1 mmHg respectively and reduced MPO2 to 23±1mmHg (all P<0.05).SGLT inhibition normalizes CPO2, which implies that increased proximal tubule transport contributes to the development of hypoxia in the diabetic kidney. However,SGLT inhibition reduced oxygen availability in the medulla. This may result from the diversion of sodium reabsorption to more distal nephron segments within the medulla, where sodium transport requires more oxygen consumption.
Renal Structure‐Function Relationship in the Obese ZSF1 Rat Model of Diabetic Nephropathy
Authors: Kuo Jay , Lee Chung Wein , Qian Hu Sheng , Fryer Ryan 
Published: June 2021

Although the obese ZSF1 rat is a preclinical model of type 2 diabetic nephropathy (DN) with marked renal dysfunction and structural derangement, the course of disease progression has not been evaluated in an age‐dependent manner. This study characterizes temporal changes in renal function relative to changes in proteinuria and glomerular and tubulointerstitial structure to further understand renal disease progression in this model.Male obese ZSF1 rats were aged to 20, 25, 30, 35, or 40 weeks of age. At those times, proteinuria (UPCR) and GFR (anesthetized, FITC‐inulin, kidney weight (KW) normalized) were measured. The left kidney was processed for histopathological analyses of glomerular lesions (% glomerulosclerosis) and tubulointerstitial damage (foci number, interstitial collagen, a‐SMA, KIM‐1, ED‐1+).GFR was steady from 20 to 30 weeks of age (avg 0.71±0.06 mL/min/g KW). At 35 and 40 weeks, GFR declined markedly to 0.29±0.11 and 0.23±0.05 mL/min/g KW, respectively. Glomerulosclerosis increased steadily from 12±1% at 20 weeks to 71±2% by 40 weeks as did UPCR, glomerular lesion severity score, interstitial lesions, a‐SMA, and ED‐1. Interstitial collagen increased modestly from 20 weeks (1.3±0.2%) to 30 weeks (3.7±0.3%) and markedly increased at 35 and 40 weeks, to 8.3±0.6% and 13.3±0.9%, respectively. KIM‐1 increased to 30 weeks (7.5±0.6%) then declined at 40 weeks.In aging obese ZSF1 rats, increased UPCR and glomerulosclerosis occurred prior to the decline in GFR and further increased as GFR fell. The decreased GFR also corresponded with a marked increase in tubulointerstitial fibrosis and injury. These results, consistent with observations in human DN, also support the obese ZSF1 rat as a relevant preclinical model of DN.
Effects of Combined Endothelin A Receptor and Renin‐Angiotensin System Blockade on The Regression of Chronic Kidney Disease in 5/6 Nephrectomized Ren‐2 Transgenic Rats
Authors: Sedlakova Lenka , Kopkan Libor , Cervenka Ludek 
Published: June 2021

Study objectiveWe tested the hypothesis where the combined renin‐angiotensin system (RAS) and endothelin 1 (ETA) receptor blockade could be more effective in the slowing of progression of CKD with already established sings of renal injury than antihypertensive treatment based on isolated RAS inhibition in 5/6 nephrectomized (NX) Ren‐2 transgenic hypertensive rats (TGR).MethodsIn five groups of male rats: sham‐operated TGR; untreated 5/6 NX TGR; 5/6 NX TGR with dual RAS blockade (trandolapril 6 mg/L and losartan 100 mg/L); 5/6 NX TGR with combined treatment with RAS and ETA receptor blockade (atrasentan 5 mg/kg/day). 5/6 NX was done in age of 6 weeks and the treatments were initiated 6 weeks after 5/6 NX. Rats were placed into metabolic cages to determine albuminuria at weeks 6, 8, 12, 16, 20, 30. In other groups, concentrations of ANG II and ET1 were evaluated in the kidneys after 2 weeks of treatments.ResultsMortality of untreated 5/6 NX TGR was 100% at 17th week compared to sham‐operated rats with mortality 0% to 30th week. Mortality of 5/6 NX TGR with RAS blockade was 32 % and in group with RAS and ETA receptor blockade 37 % at the end of 30th week. In 5/6 NX TGR, both treatments reduced enhanced albuminuria, plasma and kidney ANG II and cortical ET 1 concentrations similarly.ConclusionThere is no additive effect of combined ETA receptor and RAS blockade on the regression of CKD in 5/6 NX TGR most likely due to efficient reduction of ET 1in the renal cortex by the dual RAS inhibition.
Protective Function of Guava (Psidium guajava) Juice Combined with Trehalose in Kidney and Pancreas in Type 2 Diabetic Rats
Authors: Kuo Yen‐Ting , Chien Chiang‐Ting 
Published: June 2021

Type II diabetes (T2DM) is one of the most epidemic metabolic syndrome. Guava (Psidium guajava) has been reported anti‐oxidant, anti‐inflammatory, and anti‐diabetic ability in type I diabetic rats. To further improve the metabolic parameters, we added trehalose, which can reduce apoptosis, endoplasmic reticulum stress and oxidative stress. The present study was designed to explore the protective mechanisms of guava juice combination with trehalose in the T2DM rats.T2DM was induced in female Wistar rats by intraperitoneal nicotinamide and streptozotocin combined with high fructose diets. After successfully diabetic induction, the rats were divided into control, T2DM, T2DM with 4 ml/kg guava + trehalose (T1), 8 ml/kg guava plus trehalose (T2), 20 ml/kg guava plus trehalose (T5) or 4 ml/kg guava juice (B1) for 4 weeks. We explored the protective mechanisms by a chemiluminescence‐amplification method, immunohistochemistry, fluorescent stain and western blot.The level of fasting blood glucose, OGTT and HbA1C was significantly elevated in T2DM compared to control rats. The insulin level measured by area under curve was significantly higher in the T5 compared to T2DM rats. The level of serum and renal reactive oxygen species, 3‐nitrotyrosine‐related oxidative stress, caspase‐3‐mediated apoptosis, IL‐1β‐mediated pyroptosis was significantly higher in T2DM rats vs control rats. These oxidative parameters were significantly depressed in the groups of B1, T1, T2 and T5. Our data showed that guava juice with trehalose in T1, T2, T5 rats had less oxidative damage in the kidney and pancreas compared to B1 rats.The combination of guava juice and trehalose protects pancreas and kidney against hyperglycemia‐induced inflammation and oxidative injury.
Effect of Water and/or Food Deprivation on Renal Function
Authors: Pessoa Thaissa , Malnic Gerhard 
Published: June 2021

Acute water (WD) and/or food (FD) deprivation can occur in a variety of situations, eg. natural disasters. The knowledge of these conditions is important to improve therapies, thus the aim of the present work was to determine the effect of 24 hours WD, FD or both on renal function.Animals kept in WD presented body weight reduction and total plasma protein, hematocrit and plasma sodium increase (vs CTRL), indicating that WD causes a significant decrease in plasma volume. Animals kept in WD + FD presented no changes in all these parameters, indicating that FD has an important role in the ability to maintain plasma volume during WD. Besides, WD, FD and WD + FD decreased glomerular filtration rate (vs CTRL) but FD had the strongest effect. These results show that food intake is an important element related to glomerular control and may modify the vascular tone that can be involved with the ability to maintain plasma volume during WD.Although Na+ intake (NaI) in WD was 37% smaller, urinary Na+ excretion (UNa) had not changed (vs CTRL), showing that WD animals were in a negative Na+ balance. Besides, WD animals showed a high positive correlation between NaI, UNa and urine flow (UF), i.e. the volume of urine was higher, as urinary Na+ excretion increased and this last was higher, as NaI increased. These results show that in WD the ability to retain volume is influenced by NaI.Surprisingly, animals kept in WD + FD presented the same UF as animals in WD, although UNa decreased by 79% (vs WD) and they ingested no Na+. Besides, although in FD the UNa had decreased by 75% (vs CTRL), FD animals presented marked diuresis (UF increased 47% vs CTRL). These results show that FD modulates water excretion independently of UNa. This mechanism may influence the renal ability to retain volume when animals are kept in WD + FD.<a name=“_GoBack”></a>Financial support: FAPESP; CNPq
Contribution of Brain Gαq and Gα12 Protein Pathways in Mediating Angiotensin II (Ang II) Dependent Hypertension
Authors: Gao Juan , Kapusta Daniel 
Published: June 2021

Our previous studies demonstrated that down‐regulation of brain Gα12 proteins blunted Ang II‐induced hypertension in rats. In this study, we examined whether brain Gαq proteins also contribute to Ang II‐dependent hypertension and whether the combined down‐regulation of brain Gαq and Gα12 proteins further attenuates the increase in blood pressure (BP) to Ang II. Methods: Sprague Dawley rats were implanted with telemetry transmitters for measurement of BP. After 3 days of baseline BP recording, rats were distributed into 3 groups (n=6/group) for i.c.v. infusion (mini‐osmotic pump) of scrambled (SCR) oligodeoxynucleotide (ODN; 50 µg/day), Gαq ODN (50 µg/day), or Gαq ODN + Gα12 ODN (50 µg/day each). Each group also received subcutaneous mini‐osmotic pump Ang II infusion (350 ng/kg/min). BP recording was then performed daily for 14 days. Results: After 7 days of Ang II treatment, Gαq ODN infusion decreased mean blood pressure (MBP) compared to that of SCR ODN (day 7, 151±7 vs 170±10 mmHg), and i.c.v. Gαq ODN + Gα12 ODN infusion reduced MBP further (133±4 mmHg, n=6). At day 14, there was no significant difference in MAP between Ang II + Gαq ODN and Ang II + SCR ODN (163±8 vs 176±12 mmHg), but there remained a significant decrease in MBP in the Gαq ODN + Gα12 ODN group (142±6 mmHg).ConclusionsThese findings demonstrate that brain Gαq protein pathways mediate the early phase increase in BP produced by systemic administration of Ang II, whereas brain Gα12 pathways supersede in the late phase. Therapeutically, these findings also demonstrate that down‐regulation of both brain Gαq and Gα12 protein pathways is necessary to maximally attenuate Ang II‐dependent hypertension. AHA 14POST20450173 to JG; 12GRNT12060613 and P20 GM103514 to DRK
The Succinate Receptor 1 is a Physiological Regulator of the Renin‐Angiontensin Aldosterone System
Authors: Carmone Claudia , Robben Joris , Ariza Ana , Bekkenkamp Melissa , Kurstjens Steef , Devuyst Olivier , Deen Peter 
Published: June 2021

It has been shown that oxidative cell stress in diabetes type I (DMI) induces tubular release of mitochondrial succinate and that subsequent activation of the SUCNR1 in the juxta‐glomerular apparatus is needed for renin release and DMI‐induced hypertension. Here, we tested whether the SUCNR1 also has a physiological role in renal water and electrolyte handling.Blood and urine analysis of wild‐type and SUCNR1‐/‐ mice showed that loss of SUCNR1 increased sodium and albumin excretion, and reduced renal renin and plasma angiotensin II (AngII) levels. Immunoblotting revealed decreased proximal tubular and inversely related medullary abundance of sodium‐hydrogen exchanger (NHE)‐3, and decreased abundance of the epithelial sodium channel ENaC. Nitric Oxide (NO) release, and fractional excretion of urea and water were increased, coinciding with reduced AQP2 abundance. With an unchanged overall morphology, wet, but not dry, weights of kidneys of SUCNR1‐/‐ mice were significantly higher than of wild‐type littermates.Our data reveal that the SUCNR1 is essential for the physiological maintenance of renin and AngII levels, and proper proximal tubule and collecting duct sodium reabsorption. Albumin release may be secondary to the decreased cortical NHE3 expression in proximal tubules, due to reduced AngII levels. Increased NO may underlie water loss.The increased wet kidney mass is likely due to tubular dilation due to increased tubular pressure because of life‐long diuresis. Our data thus indicate that the mammalian SUCNR1 is a physiological regulator of water and volume homeostasis.