bluuebunny/crossref_metadata_2025 huggingface dataset:
Behavioral and neurobiological changes within a period of heightened susceptibility to voluntary alcohol withdrawal
Authors: McDonald Mary , Hoek Jan , Ogunnaike Babatunde , Schwaber James
Published: June 2021

In this study, we identify a time frame of increased susceptibility to voluntary alcohol withdrawal in rats, and we study the behavioral and neurobiological changes resulting from this withdrawal. Male Sprague Dawley rats were fed a liquid ethanol‐containing diet and their daily consumption was recorded. We determined that rats are most susceptible to fatal episodes of withdrawal within 10–20 days on the ethanol diet. Rats whose intake decreased severely within this period were determined to be experiencing voluntary alcohol withdrawal, and their behavior was videotaped and subsequently scored. Compared to involuntarily withdrawn chronic ethanol‐fed animals, the animals experiencing voluntary alcohol withdrawal also showed an array of behavioral signs and apparent homeostatic dysregulation to the point of death. In order to study the neurobiological changes associated with such perturbations in homeostatic and emotional control, we tested for and discovered differential gene expression in two brain regions: the nucleus tractus solitarius (NTS) and the central nucleus of the amygdala (CeA). We conclude that increased anxiety and the associated neurobiological changes may lead to the dangerous state of voluntary withdrawal, and future work will include the administration of anxiolytics to test this hypothesis. Research Support: NIH/NIAAA R01 AA13204 to JSS.
Central Administration of Nicotine Inhibits Cough in the Cat
Authors: Bolser Donald C , Rose Melanie J , Poliacek Ivan
Published: June 2021

Nicotine is a major cough‐promoting component of cigarette smoke due to its excitatory effects on pulmonary afferents. There is no information on the central actions of nicotine on the cough reflex. We speculated that central administration of nicotine would enhance cough. Electromyograms (EMG) of parasternal and transversus abdominis (TA) muscles were recorded in anesthetized spontaneously breathing cats. Repetitive coughing was elicited by mechanical stimulation of the intrathoracic trachea. (−) Nicotine (0.1–30 μg/kg) was administered via the vertebral artery and significantly reduced cough number and TA EMG in a dose‐dependent manner. (+) Nicotine (0.1–30 μg/kg, ia) also inhibited cough in a dose‐dependent manner but was approximately 30 fold less potent than the (−) isomer. In a separate group of animals, (−) nicotine (38±6 nL, 1.6 mM, 63±10 picomole) was unilaterally microinjected into the expiratory region of the caudal ventral respiratory column (cVRC). Microinjection of nicotine into the cVRC significantly reduced cough number and TA EMG amplitude during cough. The results support stereo‐selective inhibition of cough by nicotine at one or more brainstem sites. The effects of systemic administration of nicotine on the cough reflex may represent a complex balance between peripheral excitatory and central inhibitory actions. Supported by James and Esther King Biomedical Research grant 06TSP‐01.
Effects of neonatal maternal separation on HVR are no longer present in middle‐aged female rats.
Authors: Fournier Sebastien , Gulemetova Roumiana , Joseph Vincent , Kinkead Richard
Published: June 2021

Neonatal maternal separation (NMS) disrupts normal neurological development in mammals. The hypoxic ventilatory response (HVR) of adult male rats previously subjected to NMS is ∼25% greater than controls while the response of NMS females is reduced by ∼30% (Genest et al., 2004). To address the role of ovarian hormones on the respiratory phenotype observed in NMS females, we compared the HVR of adult (10–14 weeks old) with that of more mature females (53–60 weeks old) in which circulating estradiol and progesterone levels are significantly reduced. Pups subjected to NMS were placed in an incubator 3h/day for 10 consecutive days (P3 to P12). Controls were undisturbed. Rats were then reared normally until adulthood or middle age when HVR was measured with plethysmography (12% O2, 20 min). The HVR of middle‐aged females was greatly reduced compared to adults. The effects of NMS on HVR were attenuated in middle‐aged compared to younger adult females. Middle‐aged NMS females tended to have a higher HVR than controls, as observed in adult NMS males vs. controls. These results highlight the interaction between endogenous hormones and the respiratory phenotype observed in NMS animals. Supported by the CIHR.
Evidence that brain L‐arginine availability modulates heat loss during physical exercise in rats
Authors: Wanner Samuel Penna , Leite Laura Hora Rios , Marubayashi Umeko , Coimbra Cândido Celso
Published: June 2021

We investigated the effects of increased brain L‐arginine (precursor of nitric oxide synthesis) availability on thermoregulatory adjustments and physical performance in rats during exercise (18 m.min‐1 and 5% inclination) until fatigue. Under anesthesia with ketamine and xylazine, male Wistar rats received implants of a guide cannula into the right lateral cerebral ventricle and of a temperature probe into the peritoneal cavity. On the day of the experiments, core (Tb) and tail skin temperatures were measured while the rats were running after injection of 2 μL of either NaCl 0.15 M (Sal, n = 11) or L‐arginine solution (L‐arg: 0.82 M, n = 6; 1.65 M, n = 6, and 3.30 M, n = 5) into the cerebral ventricle. Heat storage rate and threshold Tb for tail vasodilation (TTbV) were calculated. L‐arg injection induced a dose‐dependent reduction in the TTbV and heat storage rate (3.23 ± 0.84 cal.min−1, L‐arg 3.30 M; 6.46 ± 1.12 cal.min−1, L‐arg 1.65 M; 8.59 ± 0.95 cal.min−1, L‐arg 0.82 M; 9.54 ± 0.94 cal.min−1, Sal; p<0.05). Although the lower Tb at fatigue point, treatment with L‐arg failed to change exercise performance (25.7 ± 3.5 min, L‐arg 3.30 M; 25.7 ± 2.4 min, L‐arg 1.65 M; 26.4 ± 2.9 min, L‐arg 0.82 M; 26.9 ± 1.7 min, Sal). These results indicate that brain nitric oxide transmission modulates heat loss during exercise, probably by reducing sympathetic vasoconstrictor tonus to skin vessels.

Supported by: CNPq, FAPEMIG e CAPES.
Effect of central application of 17‐β estradiol on thermoregulation during a cold exposure in female rats
Authors: Uchida Yuki , Tokizawa Ken , Nagashima Kei
Published: June 2021

BACKGROUND

We reported that, in ovariectomized rats, thermoregulation in the cold was attenuated. However, systemic administration of 17‐β estradiol (E2) restored the response. Moreover, E2 increased cFOS immunoreactive cells in the medial preoptic area (MPO) and dorsomedial hypothalamus (DMH) in the cold.

PURPOSE

To test the hypothesis that E2 augments central thermosensitivity to the cold, we assessed the effect of the local administration of E2 to the two hypothalamic areas on body temperature (Tb) in the cold.

METHODS

Adult female rats were ovariectomized, and a stainless steel canula was placed in the MPO, DMH, or horizontal limb diagonal band. At least 7 days after the surgery, E2 or cholesterol was administrated to this brain area through the canula. Forty‐eight hours after the administration, a rat was exposed to 10°C or 25°C environment for 2h, and Tb was measured by telemetry.

RESULTS

During the 10°C exposure, Tb increased only in the group, which was administrated E2 in the MPO. Either cholesterol nor E2 in the other brain area had no effect on Tb.

CONCLUSION

The MPO has abundant estrogen receptors and so‐called thermosensitive neurons, estrogen may modulate thermosensitivity to the cold in the MPO.
TRPV blockade by ruthenium red does not suppress thermosensitivity in hypothalamic neurons
Authors: Unger Nicholas T. , Kaple Mary L. , Boulant Jack A.
Published: June 2021

The thermoregulatory preoptic‐anterior hypothalamus (POAH) contains both temperature sensitive and insensitive neurons. While controversial, recent studies suggest that POAH neuronal thermosensitivity is due to vanilloid‐sensitive transient receptor potential (TRPV) channels. This hypothesis was tested by determining the responses of POAH neurons to ruthenium red, a ryanodine receptor antagonist that blocks TRPV‐mediated responses. Whole‐cell patch microelectrodes recorded the intracellular activity of POAH neurons in rat hypothalamic tissue slices perfused with control ACSF and experimental media containing 1–100 μM ruthenium red. Each neuron was characterized by its spontaneous firing rate at 36°C and its firing rate thermosensitivity (impulses/sec/°C) during changes in tissue temperature. Ruthenium red did not reduce the firing rate thermosensitivity nor the membrane potential thermosensitivity of POAH warm sensitive neurons. This supports our previous studies indicating that hypothalamic neuronal thermosensitivity is not determined by TRP channels nor by thermally‐induced changes in the resting membrane potential. [Supported by NIH grants NS‐14644 and NS‐045758]
Role of human brown adipose tissue in adaptive thermogenesis
Authors: van Marken Lichtenbelt Wouter D , Vanhommerig Joost W , Smulders Nanda M , Teule G J Jaap
Published: June 2021

Individual variation in cold adaptive thermogenesis can potentially be attributed to sympathetic nervous innervation of brown adipose tissue (BAT). In humans BAT was thought to be present only in infants. Recent results from PET‐CT scans indicate that adults may have significant amounts of active BAT.

The objective is to study the relation between presence and activity of BAT and the level of cold induced thermogenesis in humans.

Male volunteers (age: 24.3±3.5 y; length: 181±5.5 cm; weight: 75±4.3) were examined for presence and/or activity (standardized uptake value) of BAT during cold exposure by means of 18F‐FDG PET‐CT. In a climate chamber thermoneutral (1 h; 22 °C) condition is compared to mild cold (2 h; 16 °C). Increase in resting metabolic rate (RMR) as measured by indirect calorimetry is compared to the BAT data.

Six subjects have currently been measured. RMR (mean 4.07±0.42 kJ/min) increased between 1.5 and 25 %, depending on the subject. Five subjects showed significant amounts of BAT, especially in the supra‐clavicular region. One showed no sign of BAT.

This study shows high prevalence of BAT in young adult human males and will relate cold induced thermogenesis to BAT activity.
SKIN SYMPATHETIC NERVE FIRING TIMING AND CARDIAC CYCLE IN HYPOVOLEMIC HYPERTHERMIA FOR MEN
Authors: Kamijo Yoshi‐Ichiro , Goto Masaki , Okada Yoshiyuki , Nose Hiroshi
Published: June 2021

We tested whether skin sympathetic nerve activity (SSNA) was associated with reduced cutaneous vasodilation in hypovolemic hyperthermia. Seventeen young men were divided into 2 groups; normovolemia (N, n = 8) and 9% hypovolemia with diuretics (L; n = 9). After 5‐min baseline measurement, they were warmed for 45min with a perfused suit until esophageal temperature rose by 0.4°C, while SSNA was recorded from the peroneal nerve (microneurography), skin blood flow (SkBF; laser‐Doppler flowmetry) on the dorsal foot, and mean arterial pressure (MAP; tonometry). Although a rising rate of cutaneous vascular conductance (CVC, SkBF/MAP) during warming was 50% lower in L than N (P<0.05), rising rates of burst frequency and amplitude of SSNA, rectified and filtered with low pass edge of 1.6Hz, were similar between N and L. Then, to assess the relationship between SSNA firing timing and cardiac cycle, an incidence of raw SSNA spikes was counted every 0.1s bin for 3s after every R wave of ECG. In an averaged histogram of spike incidence every 1min, the peaks appeared at the same interval as those of R and the peak interval of spike (IS) was highly correlated with that of R (IR) in N (n = 399, r = 0.92) and L (n = 443, r = 0.78) for 50 min (both, P<0.001). Also, standard deviation of [IR‐IS] (SDR‐S) in L was 36% higher than N (P<0.05), inversely correlated with the increase in CVC (r=−0.64, P<0.01). Thus, SDR‐S may be linked with reduced CVC in hypovolemia.
Vasculature Changes and Blood Pressure Reductions Following Both Resistance and Aerobic Training Despite Age or Body Fatness in Hypertensive Individuals
Authors: Carta Kerin M , Ferechette Vincent , Fernhall Bo , Tobin Melissa Marie , Collier Scott Robert
Published: June 2021

The benefits of exercise training on blood pressure (BP) are well established, but the effects of age and obesity status on resting hemodynamics and vasculature changes have not been elucidated in hypertensive patients. The purpose of this study was to determine the impact of age and weight on hemodynamics and arterial stiffness following resistance and aerobic training in a population with elevated blood pressure. Thirty‐two pre or stage 1 essential hypertensives (21 Males and 11 females) who were not taking any medications were recruited (Age= 48±1.3 yrs, Height 172±1.8cm, Weight 90.1±3.8kg, SBP 140±2.4 mmHg, DBP 80±1 mmHg) and were randomly assigned to 4‐weeks of resistance (RE) or aerobic (AE) training (16 in each group). Before and after training we obtained measures of resting BP and arterial distensibility (pulse wave velocity). While mode of exercise did have an effect on arterial distensibility (RE increased stiffness and AE decreased stiffness), age and obesity status did not show a significant effect. Further, AE and RE both lowered resting BP significantly with no difference between mode of exercise.
NAD(P)H oxidase inhibition upregulates anti‐apoptotic BAG‐4 protein expression in the mdx diaphragm
Authors: Kim Jong‐Hee , Kwak Hyo‐Bum , Lawler John M
Published: June 2021

Duchenne muscular dystrophy (DMD) is the most devastating type of MD resulting in oxidative stress, muscle damage, weakness, and wasting in locomotor and respiratory (e.g., diaphragm) muscle. Previously, we showed that apocynin, a NAD(P)H oxidase inhibitor, protects against reduction in diaphragm mass, oxidative capacity, and apoptosis in 3–4 week old mdx mice. BAG family proteins regulate cell survival and contain a conserved domain binding Bcl‐2, TNF‐R1 and HSP70. We hypothesized that apocynin (1.5mmol/L per day) would upregulate BAG‐1, BAG‐4, and HSP70, while decreasing TNFR1 in the mdx diaphragm. Eight to nine weeks old mdx mice and age‐matched C57BL wild‐types were divided into 4 groups: wild‐type controls + water (WW, n=7); wild‐type controls + apocynin (WA, n=7); mdx mice + water (MW, n=7), and mdx mice + apocynin (MA, n=7). After 7 days of treatment, diaphragm and gastrocnemius muscle were extracted. BAG‐4 levels were significantly higher in MA than MW, whereas BAG‐1 levels remain unchanged both WA and MA. TNFR1 levels were significantly lower in WA compared to WW. HSP70 levels were elevated in mdx mice with and without apocynin. Cleaved caspase‐3 was elevated in the mdx diaphragm, but reduced with apocynin. Our data suggest that apocynin may foster cell protection in the mdx diaphragm via BAG‐4 signaling.

Supported by a grant from NIH (AR054084)
Chromatin Responses to DNA Damage
Authors: Shen Xuetong , Morrison Ashby
Published: June 2021

Proper repair of DNA damage is critical in preventing genome instability and carcinogenesis. While the role of ATP‐dependent chromatin remodeling in transcription is well established, a link between chromatin remodeling and DNA repair has remained elusive. We have found that the evolutionarily conserved INO80 chromatin remodeling complex directly participates in the repair of a double strand break (DSB) in yeast. Our findings reveal a new role of ATP‐dependent chromatin remodeling in nuclear processes and suggest that an ATP‐dependent chromatin remodeling complex can read a DNA repair histone code. We have also found recently that a subunit of the INO80 complex is phosphorylated in an ATM/ATR‐dependent fashion in response to DNA damage, and the phosphorylation events modulate DNA checkpoint pathways. Thus, chromatin responses to DNA damages involve complex changes in both histones and complexes that regulate chromatin.
Characterizing Diabetic Myopathy: Muscle Contractility and Phenotype of Akita and STZ Diabetic Murine Models
Authors: Krause Matthew Paul , Imam Abdullah , Cafarelli Enzo , Riddell Michael C , Hawke Thomas J
Published: June 2021

Steptozotocin (STZ) induced diabetes impairs skeletal muscle function and alters muscle morphology, though recent evidence suggests these changes are a result of the STZ rather than diabetes per se. Thus, the phenotype of diabetic skeletal muscle remains unclear. The Akita mouse is a type 1 diabetes (T1DM) model that displays many similarities to human T1DM including adolescent onset. The purpose of the study was to determine the phenotype and functionality of skeletal muscle in diabetic Akita mice (+/–) vs. non‐diabetic littermates (+/+). Following 10 weeks of overt diabetes in the +/– mice, functional capacity of the gastrocnemius muscle was assessed using in situ electrical stimulation. Body weight (−13 ± 2%), muscle mass (−17 ± 3%), heart mass (−9 ± 2%) and epidydymal fat mass (−81 ± 3%) were less in +/– than +/+ mice. Further, +/– gastrocnemius had more type IIA (+29 ± 6%) and less IIB/D (−24 ± 6%) fibers than +/+. Functionally, peak tetanic force and low frequency stimulation fatigue rates were not different between groups. These data indicate that untreated T1DM attenuates growth and alters skeletal muscle phenotype, but does not appear to alter peak force or low frequency stimulation endurance capacity.
D‐Glucose increases the expression and activity of hCAT‐1 and Sp1 binding to SLC7A1 promoter in human umbilical vein endothelium
Authors: González Marcelo , Farías Marcelo , Casanello Paola , Sobrevia Luis
Published: June 2021

L‐Arginine is mainly transported by the human cationic amino acid transporter 1 (hCAT‐1, protein codified by the gene SLC7A1) in human umbilical vein endothelial cells (HUVEC). hCAT‐1 mediated L‐arginine transport and nitric oxide (NO) synthesis are increased by 25 mM D‐glucose in this cell type. Since Sp1 is a transcription factor activated by NO, we studied whether high D‐glucose effect on transport was due to altered expression of hCAT‐1 and abundance and activity of the transcription factor Sp1 in primary cultures of HUVEC. D‐Glucose (25 mM, 24 hours) increased (~3.2 fold) the maximal velocity (Vmax), without altering the apparent Km, of L‐arginine transport compared with cells in 5 mM D‐glucose. High D‐glucose also increased the hCAT‐1 mRNA number of copies (~5‐fold) and protein abundance (~2‐fold), and Sp1 nuclear abundance and binding to SLC7A1 promoter region (−177 to −103 bp from ATG). Thus, the stimulatory effect of D‐glucose on L‐arginine transport could result from increased expression of hCAT‐1 due to increased activity of Sp1 on the promoter of SLC7A1 in HUVEC.

Supported by FONDECYT 1070865, VRAID BM16/2007. MG holds a CONICYT PhD fellowship and PhD Thesis Support grant (CONICYT 23070213).
Essential Role of Cofilin‐1 and mDia1 in Regulating Thrombin‐Induced Actin Dynamics and RelA/p65 Nuclear Translocation in Endothelial Cells
Authors: Fazal Fabeha , Bijli Kaiser M , Minhajuddin Mohammad , Finkelstein Jacob N , Rahman Arshad
Published: June 2021

Activation of the small GTPase RhoA and associated changes in actin dynamics control thrombin‐induced NF‐κB activation and ICAM‐1 expression in endothelial cells. However, the events acting downstream of RhoA to mediate the changes in actin dynamics required for NF‐κB activation and ICAM‐1 expression remain unclear. Here we show that thrombin engages cofilin 1 and mDia1 downstream of RhoA to regulate these responses in endothelial cells. Stimulation of human umbilical vein endothelial cells with thrombin resulted in Ser‐3 phosphorylation/inactivation of cofilin in a ROCK‐dependent manner. RNAi knockdown of cofilin‐1 stabilized the actin filaments and prevented thrombin‐ and RhoA‐induced NF‐κB activity. In parallel experiments, knockdown of mDia1 destabilized the actin filaments and inhibited thrombin‐ and RhoA‐induced NF‐κB activity. Inhibition of NF‐κB activity and ICAM‐1 expression following stabilization and destabilization of actin filaments by these approaches occurred downstream of IκBα degradation and was associated with impaired RelA/p65 nuclear translocation and consequently, RelA/p65 binding to DNA. These findings support the notion thatspecific alterations in actin dynamics induced by thrombin are mediated by concerted actions ofcofilin‐1 and mDia1 and are necessary for RelA/p65 nuclear localization, and thereby ICAM‐1 expression in endothelial cells.

This abstract is funded by: ALA, NIH HL067424.
Role of CB2 cannabinoid receptors in interplay between endothelium and inflammatory cells: implications for ischemia‐reperfusion injury and atherosclerosis.
Authors: Pacher Pal , Mukhopadhyay Partha , Rajesh Mohanraj , Bátkai Sandor , Kunos George
Published: June 2021

Recently, targeting CB2 cannabinoid receptors with selective agonists may represent a novel therapeutic avenue in various inflammatory diseases, including atherosclerosis, but the mechanisms by which CB2 activation exerts its anti‐inflammatory and anti‐atherogenic effects and the cellular targets have remained elusive. We have studied the effects of CB2 receptor activation on TNF‐alpha‐induced signal transduction of human coronary artery endothelial and human liver sinusoidal endothelial cells (HCAECs and HLSECs) and on endotoxin‐induced vascular inflammatory responses in vivo, as well as in a mouse model of hepatic ischemiareperfusion injury. CB2 receptor activation with selective agonists attenuated TNF‐alpha‐triggered NF‐kappaB and Rho A activation, up‐regulation of ICAM‐1 and VCAM‐1, expression of monocyte chemoattractant protein in endothelial cells, transendothelial migration of monocytes, monocyte‐endothelial, and neutrophilendothelial adhesion in vitro, as well as the endotoxin‐induced vascular inflammatory response and ischemia‐reperfusion injury in vivo. The above mentioned endotoxin‐ and TNF‐alpha‐induced phenotypic changes are critical in the development of reperfusion injury, initiation and progression of atherosclerosis and restenosis, and cardiovascular aging, and may thus represent the mechanisms underlying the therapeutic effectiveness of CB2 receptor activation in these pathologies.
Mutation of the Caveolin‐Scaffolding Domain Reduces Phosphofructokinase Localization to the Plasma Membrane in Vascular Smooth Muscle
Authors: Hernandez Mark J. , Hardin Christopher D.
Published: June 2021

We have previously demonstrated the role of caveolin‐1(CAV‐1) as a scaffold to localize glycolytic enzymes to the plasma membrane. Because the caveolin scaffolding domain (CSD) has been implicated in the interaction of caveolins with proteins that reside in the caveolae we sought to investigate the role of the CSD in targeting PFK in smooth muscle. We disrupted the CSD's ability to target PFK by site directed mutagenesis of a single residue without altering the membrane localization of the mutant CAV‐1. Using in vitro site directed mutagenesis we mutated aromatic amino acid phenylalanine F92, a highly conserved residue found in all three caveolins isoforms that is essential for interaction in vivo, to amino acid residue glycine. We previously reported CAV‐1 overexpression resulted in the targeting of PFK to the membrane. Here we report that only 34.3 % of PFK localized with CAV‐1 after overexpression of mutant CAV‐1, in contrast to 69.2 % of PFK which localized with CAV‐1 after overexpression of wild type CAV‐1. These results show CAV‐1 membrane distribution without targeting PFK to the membrane after transfection of mutant CAV‐1. We propose that an interaction of CAV‐1 with PFK exists through interaction of the CSD with a binding motif in PFK. Support by NIH DK 60668.
Angiotensin receptor‐blockade improves the net balance of cardiac and skeletal muscle calcium handling protein expression and restores cardiac function in heart failure
Authors: Ferreira Julio Cesar Batista , Pereira Marcelo , Bueno Carlos Roberto , Mattos Katt Coelho , Coelho Marcele , Krieger Jose Eduardo , Brum Patricia Chakur
Published: June 2021

We tested whether losartan would improve ventricular function and reverse both cardiac and skeletal Ca2+ handling abnormalities in mice lacking α2A‐ and α2C‐ adrenoceptors (KO), which display sympathetic hyperactivity‐induced HF. Losartan (10 mg.kg−1.day−1) was administered by tap water during 8‐wk (from 5 to 7 months of age, when cardiomyopathy is in an advanced‐stage). KO mice displayed reduced fractional shortening, cardiac dilation, exercise intolerance, lung edema, increased cardiomyocyte width and increased ventricular collagen content. Cardiac dysfunction was paralleled by changes in both cardiac and skeletal Ca2+ handling abnormalities, such as decreased cardiac SERCA2 while increased NCX, and decreased soleus SERCA2 and NCX expression levels compared with age‐matched WT. Losartan treatment in KO mice restored fractional shortening, cardiac chamber size and exercise tolerance. As expected, losartan reduced cardiac myocyte width and ventricular fibrosis in KO mice. Interestingly, losartan treatment in KO mice increased cardiac SERCA2 expression towards WT levels, which was paralleled by decreased phospho‐Ser16‐PLN and phospho‐Thr17‐PLN. Likewise, losartan treatment in KO increased soleus SERCA2 expression to WT levels, while it had no impact on cardiac and skeletal NCX expression. Altogether, we provide evidence that losartan induces ventricular reverse remodeling and improves cardiac function in KO mice. This response is associated to an improved net balance of cardiac and skeletal Ca2+ handling protein expression. FAPESP 04/04042‐0
Vascular Effects of Prostacyclin and L‐NMMA in Aging
Authors: Nicholson Wayne Thomas , Vaa Brianna E , Hesse Christiane , Somaraju Lakshmi P , Pike Tasha L , Curry Timothy B , Dietz Niki M , Eisenach John H , Joyner Michael J
Published: June 2021

The vascular effects of prostacyclin and contribution of endothelial derived nitric oxide (NO) to prostacyclin mediated dilation are unknown in aging. A pilot study was performed in healthy older subjects (n=6, 61–73 years old) and younger controls (n=6, 19–45 years old) that were matched for BMI. Subjects underwent brachial artery catheterization and received escalating doses of epoprostenol (PGI2 2.5, 5, 10 ng/100ml forearm tissue/min) followed by sodium nitroprusside (SNP 0.25, 0.5, 1 mcg/100ml forearm tissue/min) after PGI2 washout. SNP and PGI2 were repeated after NO synthase inhibition with NG‐Monomethyl‐L arginine acetate (L‐NMMA 1mg/min after 50mg load). Using venous occlusion plethysmography, forearm vascular conductance (FVC) was calculated using mean arterial pressure (MAP), as FVC= (FBF/MAP X 100). Percent change in FVC from baseline after PGI2 was lower in the aging individuals (47, 160, 227 % change FVC) compared to younger controls (85, 218, 327 %change FVC) (p=0.039), L‐NMMA reduced baseline FVC similarly, and the dilator response to PGI2 was no longer significant between groups. SNP effects were not significant between groups and unaffected by L‐NMMA. This data suggests a reduced effect to prostacyclin in the aging individual may be due to a reduction in the contribution of endothelial derived NO. Support provided by HL‐46493 and UL1‐RR24150.
Arterial pressure variability, baroreflex sensitivity and organ damage in one clip, one kidney (1K1C) hypertensive conscious mice
Authors: Borges Giulianna Rocha , Silva Carlos Alberto Aguiar , Prado Cibele M. , Rossi Marcos A. , Salgado Helio Cesar , Fazan Rubens
Published: June 2021

This study aimed to evaluate arterial pressure variability (APV), baroreflex sensitivity (BRS) and end‐organ damage in conscious one kidney, one clip (1K1C) hypertensive mice. Under tribromoethanol anesthesia, Swiss mice received a silver clip around the right renal artery associated with contralateral nephrectomy (n=17). Sham operated mice (n=22) were submitted to left nephrectomy. After 4 weeks mice were equipped with catheters placed into the left carotid artery, and had the arterial pressure (AP) recorded. Standard deviation of systolic AP was defined as systolic APV while BRS was calculated using the sequence method. Mice were killed by decapitation and the hearts submitted to histological analysis. 1K1C hypertensive mice exhibited marked cardiac hypertrophy characterized by increase of the diameter of left ventricular myocyte (13.58±0.84 vs 15.37±1.54 μm) and septum myocyte (10.55±0.65 vs 12.10±0.42 μm). Left ventricular (1.49±0.019 vs 1.23±0.16 mm) and septum (1.35±0.21 vs 1.11±0.09 mm) wall thickness were also increased in 1K1C hypertensive mice. 1K1C hypertension was associated with decreased BRS (0.96±0.13 vs 0.32±0.05 bpm/mmHg) and elevated systolic APV (3.9±0.2 vs 5.4±0.5 mmHg). There were no alterations in the collagen content of the groups studied. In conclusion, 1K1C hypertension in mice displayed reduced BRS, increased APV, and cardiac hypertrophy. Support: FAPESP and CNPq.
Pregnancy Blocks the Hypertensinogenic Effect of Ouabain in Sprague‐Dawley Rats
Authors: Jacobs Brandiese , Hamlyn John
Published: June 2021

Ouabain‐like inhibitors are elevated in ∼50% of patients with essential hypertension and patients with pre‐eclampsia (PE). Prolonged administration of ouabain induces hypertension in Sprague‐Dawley rats. Accordingly, we hypothesized that ouabain might induce PE in otherwise normal pregnant rats. We implanted ouabain pellets subcutaneously in pregnant (E10) and non‐pregnant rats and measured their blood pressures (BP) weekly by tail cuff. After delivery, trunk blood was collected to determine ouabain‐like activity by radioreceptor assay. Ouabain pellets raised BP significantly in non‐pregnant rats (+18.3 mmHg, p<0.05) compared to non‐pregnant controls (+5.4 mmHg). Surprisingly, there was no significant difference in BP between pregnant rats with ouabain and their pregnant controls. Moreover, there was a significant increase in ouabain‐like activity in all pregnant (57.0 ± 3.1 nmoles plasma equiv/L) verses non‐pregnant (12.4 ± 1.1 nmoles plasma equiv/L) rats, irrespective of BP. These data show 1) that normal pregnant rats become resistant to the hypertensive effect of ouabain; 2) the pregnant state is associated with elevated levels of polar ouabain‐like materials that compete with 3H‐ouabain for binding to Na/K‐ATPase. These ouabain‐like factors may act to prevent increases in BP, or oppose the hypotensive effects of pregnancy. Funded by NHLBI 078870/75584, NIGMS Initiative for Minority Student Development Grant (R25‐GM55036), and Procter and Gamble
Air jet stress (AJS) induces ET‐1 mediated reactive oxygen species (ROS) production that increases blood pressure in Dahl salt‐sensitive (DS) rats.
Authors: Loria Analia Silvina , D'Angelo Gerard , Pollock David M , Pollock Jennifer S
Published: June 2021

We have previously reported that AJS elicits increases in plasma endothelin‐1 (ET‐1) and blood pressure. Because ET‐1 increases ROS in vascular and neuronal tissue, we tested the hypothesis that the AJS‐induced increase in blood pressure is influenced by ET‐1‐dependent ROS production. AJS was induced in male DS rats (9–10 weeks old on a normal salt diet) once per week over 2 weeks by administration of air jet pulses (3 min). Animals were untreated (C) (week 1), or given either tempol (1 mM in drinking water) or a non‐selective ETA/B receptor antagonist (A‐182086, 30 mg/Kg/day in food) (week 2). In telemetry‐instrumented rats, the AJS‐induced pressor response was significantly reduced in tempol treated rats vs. Co (15.9 ± 2.5 vs. 27.2 ± 3.8 mmHg × 3 min, p < 0.05). In addition, tempol enhanced the blood pressure recovery vs. C (p< 0.05). Pre‐treatment with A‐182086 blocked the AJS‐induced pressor response vs. C (6.9 ± 6.7 vs. 43.8 ± 12.2 mmHg × 3 min, p<0.05) and enhanced the post‐stress recovery vs. C (p < 0.05). ETA/B receptor blockade abolished the AJS‐mediated rise in plasma 8‐isoprostane (43 ± 5 to 41 ± 4 pg/ml) compared with C (37 ± 3 to 63 ± 8 pg/ml, p <0.05). These findings suggest that AJS stimulates the ET‐1 pathway that activates ROS production. Activation of ROS contributes to the AJS‐induced increase in pressor response and blunting of the blood pressure recovery in DS rats.
Interplay of superoxide, nitric oxide and peroxynitrite in doxorubicin‐induced cell death
Authors: Pacher Pal , Mukhopadhyay Partha , Rajesh Mohanraj , Bátkai Sandor , Haskó György , Szabo Csaba
Published: June 2021

Cell death is a key component in Doxorubicin (DOX)‐induced cardiotoxicity, but its mechanisms are elusive. In a mouse model of DOX‐induced heart failure, we demonstrate marked increases in myocardial apoptosis, iNOS expression, NO, and mitochondrial superoxide generation, 3‐nitrotyrosine(NT) formation, MMP2/9 gene expression, poly(ADP‐ribose) polymerase activation (without changes in NOX1, NOX2, p22phox, p40phox, p47phox, p67phox, xanthine oxidase, eNOS, nNOS), and a decrease in myocardial contractility. Pre‐treatment of mice with peroxynitrite scavengers attenuated DOX‐induced myocardial apoptosis and dysfunction. Doxorubicin dose‐dependently increased mitochondrial superoxide and NT generation, and apotosis/necrosis in cardiac‐derived and endothelial cells. The DOX‐ and/or peroxynitrite‐induced apoptosis/necrosis positively correlated with intracellular NT formation, and could be abolished by scavengers. The DOX‐induced cell death was also attenuated by selective iNOS inhibitors. In contrast, various NO donors if co‐administered with DOX, but not alone, dramatically enhanced DOX‐induced cell death with concomitant increased NT formation and decreased mitochondrial superoxide generation. Thus, peroxynitrite is a major trigger of DOX‐induced cell death, and its effective neutralization can be of significant therapeutic benefit.
Severe Effects of Anesthetic Induction Agents in the Cardiovascular Profile of Diabetic Rats.
Authors: Quidgley Jose , Portilla Peter , Zalacain Joaquin , Cruz Nildris , Crespo Maria J
Published: June 2021

Diabetic patients have a higher incidence of cardiovascular diseases and are more prone to surgical procedures than non‐diabetics. However, there is lack of studies regarding the most appropriate anesthetic induction agent for these patients. In this work, we assessed the cardiovascular effects of the minimal dose required for induction of anesthesia with either propofol (PRO, 50 mg/kg, IP), etomidate (ETO, 20 mg/kg, IP) or ketamine (KET, 100 mg/kg, IP) on Sprague‐Dawley rats 4 weeks after diabetes induction (Streptozotocin, STZ, 65mg/Kg, IP). Age‐matched non‐diabetic rats (CT) were used for comparison. Systolic blood pressure (SBP) and echocardiographic studies including heart rate (HR), stroke volume (SV), and cardiac output (CO) were evaluated. Results demonstrate significant differences between STZ and CT in all studied parameters. KET lowered SBP, SV, HR, and CO in STZ rats by 36.8%, 23.4%, 29.9% and 47.7% respectively when compared to CT (N= 7, P<0.05). In contrast ETO increased SBP by 76.7% (P<0.05) but decreased SV, HR and CO by 17.7%, 34.2% and 48.5% respectively when compared to CT (N= 7, P<0.05). PRO increased SBP by 37.9% (P<0.05) but did not modify HR, SV or CO when compared to CT. These results suggest that diabetes alters the physiological responses to anesthetic induction agents. This study has strong implications for diabetic patients where alterations in their response to these agents are expected.
Liver X Receptor activator inhibits AngII induced hypertrophic responses in rat neonatal cardiomyocytes
Authors: Yin Ran , Ricks Ernest , Li Yuquan , Yang Qinglin
Published: June 2021

The progression of cardiac hypertrophy and heart failure involves a maladaptation in energy homeostasis. Proteins involved in this key energy metabolic pathway aretranscriptionally regulated by members of the nuclear receptorsuperfamily, such as PPARs and ERRs. The Liver X Receptors (LXRα and LXRβ) are members ofthe nuclear hormone receptor superfamily. These sterol‐responsivetranscription factors regulate the expression of a number ofgenes involved in lipid and glucose metabolism. We hypothesize that LXRs play important roles in regulating the adaptive substrate switch in cardiac hypertrophy and heart failure. We investigated how a LXR synthetic ligand T1317 influences AngII induced hypertrophic responses in cultured rat neonatal cardiomyocytes. We found AngII can induce upregulation of LXRalpha transcript levels in cultured cardiomyocytes (n=4, P<0.05). Pretreatment of a LXR T1317 (1, 5, 10 uM) in cultured cardiomyocytes 2 hours prior to the 24 hour AngII treatment prevented hypertrophic responses. T1317 pretreatment suppressed an AngII induced elevation of protein synthesis in cardiomyocytes (n=6, P<0.05). Furthermore, T1317 pretreatment prevented an AngII induced increase of cell surface size (n=25, P<0.05). T1317 pretreatment also suppressed the expression of hypertorphic marker ANF induced by AngII treatment. Therefore, we conclude that LXRs play important roles in regulating cardiomyocyte growth, possibly by regulating intracellular energy balance.
Electrophysiological characteristics of freshly isolated ventricular myocytes from Zebrafish (Danio rerio)
Authors: Brette Fabien , Cros Caroline , Dixey Hayley , Wilson Christopher , Luxan Guillermo , Shiels Holly A
Published: June 2021

The Zebrafish (ZF) is a tropical fish that has been the focus of an increasing number of developmental studies. However, our understanding of the basic physiology of ZF, in particular cardiac excitation‐contraction coupling is limited. Indeed, there is currently no information about the electrical activity of single myocytes freshly isolated from ZF ventricle; this study addressed this point. Ventricular myocytes were obtained by enzymatic digestion. The patch clamp technique was used to record Na currents (INa), Ca currents (ICa) and action potentials (AP). Results are presented as mean±SE and assessed with paired t‐test. Single ventricular myocytes from ZF are long and thin, as described for other fish species. Cell capacitance was 25.5±0.9 pF (n=81). ICa density (at 0 mV) was −8.4±3.4 pA/pF and INa density (at −40 mV) was −106±18 pA/pF (n=6). Resting membrane potential was −66±2 mV (n=19). At 0.1 Hz stimulation frequency, AP duration at 25, 50, and 90% repolarization was 53±16, 117±26, 155±35 ms, respectively (n=12), indicating the presence of a plateau phase. Increasing stimulation frequency to 2 Hz significantly decreased AP duration (n=12, p<0.05). To conclude, we have developed a method to obtain viable isolated ventricle myocytes from ZF heart. The presence of a plateau during the AP suggests that this species might be appropriate for ion channels related mutation screening of cardiac alteration.
Electrocardiogram based biodosimetry to assess acute radiation injury
Authors: Shukla Jyoti , Chatterjee Saurabh , Thakur V.S. , Poduval T.B.
Published: June 2021

Nuclear accidents are associated with the acute radiation syndrome (ARS).The effect ARS on the cardiac function has not been yet studied. Further to develop approaches to prophylaxis, mitigation and treatment of radiation injuries one needs appropriate animal models to accurately identify the biosignature of ARS. Considering the above we have studied the electrocardiogram pattern of ARS induced by total body radiation (TBI) of mice in an attempt to (a) identify the effect of TBI on heart, (b) to use this method to identify the potential biological response modifier (BRM) capable of reversing the radiation injury. The results indicated TBI leads to ST elevation (fig 1b), reduced heart rate and increased RR interval compared to sham group (fig 1a), which is an indication of myocardial dysfunction. We used L‐arginine (LA), a known BRM that reverses the radiation injury depending on the therapeutic window. When LA was administered at +2h of TBI, the above electrophysiological parameters were restored to normalcy (Fig 1d). However, when LA was given before TBI, no reversal of TBI induced cardiac dysfunction was observed (fig 1c). Considering BRMs operate at the whole animal level rather than cellular level this new ECG based biodosimetry method will be very useful in monitoring ARS and identifying potential radiomodifiers. Further considering there is an absence of a simple, noninvasive biodosimetry to assess the ARS, the above method could be very useful.
Scaling of the retinogeniculostriate pathway in mammals
Authors: Willms Jonathan , Heesy Christopher Paul
Published: June 2021

Studies of the relative sizes of brain components in mammals suggest that areas responsible for sensory processing, including visual processing, are correlated with aspects of ecology. Primate orbit convergence and binocular vision are correlated with overall size of the brain as well as components of the visual pathway, such as the lateral geniculate nucleus. The question remains whether components of the visual pathway (optic tract, lateral geniculate nucleus, and primary visual cortex) are similarly correlated in non‐primate mammals.

This study examines the relationship between orbit convergence, binocular field overlap, overall brain size, and the volumes of components of the visual pathway. Data on orbit orientation are combined with those on overall brain size in primates, and non‐primate mammals. In addition, data on brain component volumes were collated for a subset of these taxa. Volumetric data on neural components of the visual pathway are correlated with convergence among the taxa included in this study. Binocular taxa have relatively larger optic tracts, lateral geniculate nuclei and primary visual cortices when brain volume is held constant. Primates are not unique in the relationship between binocularity and brain size; however, since primates are the most binocular of the mammals, they also have the relatively largest components of the visual pathway.
Double tendon of the Human Extensor Indicis Muscle provides “insight' into individual development
Authors: Kumka Myroslava
Published: June 2021

Methods: This study utilized 16 embalmed cadavers (32 upper limbs) of both sexes and of different ages using traditional anatomical macro‐micro dissections.

Summary of results: The variant of the Extensor Indicis (EI) muscle: double tendon to index and middle fingers, was found in one female cadaver, bilaterally. The narrow, elongated muscle belly of EI attached to the posterolateral surface of ulna, the adjacent interosseus membrane and the deep antebrachial fascia. The lateral part of the EI muscle belly became tendonous at the inferior third of the forearm while that of the medial part occurred at the superior border of the extensor retinaculum. Both tendons passed deep to the extensor retinaculum to join with the ulnar sides of the tendons of the extensor digitorum forming the extensor expansion for the index and middle fingers. It was observed that the muscle belly of this anomalous muscle was innervated by branches of the deep radial nerve in the inferior third of forearm. The double EI tendon appears to be a developmental variant of the normal migratory pattern of myogenic cells known to occur during embryogenesis of the upper limb.

Conclusion: Our finding supports the hypothesis that the double EI muscle tendon variant may result from early splitting of EI muscle primordium during morphogenesis and may serve to enhance tightness of grip and functional independence to the index and middle fingers.

No external support.
Bewo cell culture infected with HBV
Authors: Li shuzhen , Wang suping
Published: June 2021

The purpose of this paper is to construct a model in vitro of hepatitis B virus (HBV) infecting the human trophoblast in mother‐to‐child transmission during pregnancy through demonstrating the susceptibility of Bewo cells culture to infection with HBV. We carried out a study of HBV infected Bewo cells. The human trophoblast cell line Bewo were co‐cultured with HBV DNA positive sera for 24 hours and the infected Bewo cells were continually cultured for 3 days. HBV DNA in Bewo culture supernatant and HBsAg in infected Bewo cells were detected by Fluorescence Quantitative PCR and Immunohistochemistry ABC . Study for cell morphology and growth showed no significant difference between infected Bewo cells and uninfected control. HBV DNA was successfully detected in the supernatant of infected Bewo cells. HBsAg were successfully detected in infected Bewo cells after co‐culturing for 24 hours with HBV DNA positive sera. We found the human trophoblast cell line Bewo can be infected by HBV through co‐culture with HBV DNA positive sera. The model can be used to study the mechanisms of HBV infection in placenta.
Immunologic Response to (1,4)‐α‐D‐Glucan in the Lung and Spleen of Endotoxin‐Stimulated Rats
Authors: Torbati Dan , Ramachandran Cheppail , Totapally Balagangadhar R.
Published: June 2021

We investigated the effects of (1,4)‐α‐D‐glucan (α‐DG), a novel immune stimulator drug from Tinospora cordifolia, on pro‐ and anti‐inflammatory cytokines balance in the lung and spleen of endotoxin‐stimulated rats. Experimental groups (n=16/group) included, controls with an intraperitoneal injection of saline, endotoxemic rats with a non‐lethal dose of 10 mg/kg E‐coli endotoxin, and rats treated with two doses of 10mg/kg α‐DG, intraperitoneally, at 2 and 4‐h after endotoxin injection. A 24‐h after saline/endotoxin injection rats were euthanized and the lung and spleen were removed for cytokine profiling. Endotoxemia increased IL‐1β concentration by about 5‐fold in both organs. The lung and spleen showed different responses to endotoxemia. In the lung, α‐DG treatment created approximately 30% (p>0.05), 43% and 46% (p<0.01) reductions in IL‐1β, IL‐6, and INF‐γ concentration, respectively, as compared to endotoxemia (ANOVA followed by Tukey‐Kramer test). In the spleen, the ratio of IL‐1βto IL‐10 concentration was reduced from 89 to 49 (55%; p<0.05), demonstrating an anti‐inflammatory trend at the 24‐h of the study (p<0.05). These data suggest that α‐DG influences the pro‐ and anti‐inflammatory cytokine balance in the lung and spleen during early endotoxemia.
Phagocytic effects of β‐glucan from Coriolus versicoloar are related with Dectin‐1 signaling and NOS and Ikaros regulation in macrophages
Authors: Park Sulkyoung , Jang Seon‐A , Lim Jung Dae , Sohn Eun Soo , Kang Nam Sung , Pyo Suhkneung , Sohn Eun Hwa
Published: June 2021

The β‐glucan receptor dectin‐1 may contribute to phagocytosis. Coriolus versicolor has been known to have immunomodulatory effects. For further understanding of the phagocytic activity and mechanisms for β‐glucan from C. versicolor, we examined phagocytosis, NO and NOS production in β‐glucan‐treated macrophages by dectin‐1 antagonist, laminarin. It showed that the treatment of β‐glucan induced a remarkable increase of phagocytosis in RAW264.7 cells, peritoneal macrophages and microglia. However, the activity of β‐glucan‐induced phagocytosis was abrogated by the pre‐treatment of laminarin. We also examined whether NO production and NOS expression are involved in phagocytosis and β‐glucan induced dectin‐1 signal pathways. Our results showed that phagocytic activity was not increased in the presence of iNOS inhibitor, S‐methylisothiourea, cNOS inhibitor and diphenylene iodonium chloride in the β‐glucan‐treated cells. The role of Ikaros in regulating phagocytic effects of β‐glucan were also determined. Taken together, these results suggest that β‐glucan enhances phagocytosis via dectin‐1 signal pathways and these effects of β‐glucan might be related to NO, cNOS, iNOS and Ikaros regulation.