bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pretreatment with either a 5‐HT2C agonist or 5‐HT2A antagonist decreases cocaine self‐administration (848.9)
Authors: Kohut Stephen , Bergman Jack , Mello Nancy 
Published: June 2021

Cocaine’s abuse related effects have been attributed to its interaction with dopamine systems. However, ligands that target the serotonin 5‐HT2C and 5‐HT2A receptor subtypes have been reported to modulate dopaminergic activity and several of the abuse related effects of cocaine. This suggests that ligands selective for specific serotonin receptor subtypes may be effective anti‐cocaine medications. The present study investigated whether pretreatment with a 5‐HT2C agonist (Lorcaserin) or a 5‐HT2A antagonist (M‐100907) could alter cocaine's reinforcing effects in rhesus monkeys. Two groups of male rhesus monkeys (n=4/group) were trained under a fixed ratio 30 (FR30) schedule to respond for food (1 g banana flavored pellets) and cocaine (0.01 mg/kg/inj). Baseline cocaine (0.003‐0.1 mg/kg/inj) self‐administration followed an inverted‐U shaped function with maximal rate of responding at 0.01 mg/kg/inj. Pretreatment with Lorcaserin (0.56 or 1.0 mg/kg, IM) or M‐100907 (0.32 or 1.0 mg/kg, IM) reduced rate of responding for doses of cocaine at the peak and on the descending limb of the function. Food‐maintained responding was only modestly decreased after pretreatment with either serotonergic compound. These findings suggest that 5‐HT2C agonism and/or 5‐HT2A antagonism may be novel approaches to the treatment of cocaine addiction. Supported by NIDA DA002519 and DA88876.Grant Funding Source: Supported by NIDA DA002519 and DA88876.
Differential changes in vasopressin‐induced vasoconstriction in renal vascular bed and aorta from endotoxemic rats (849.5)
Authors: Guarido Karla , da Silva‐Santos José Eduardo 
Published: June 2021

Hyporesponsiveness to vasoconstrictors is a well‐known characteristic of septic shock. We hypothesized that the degree of vascular hyporesponsiveness may vary among different vascular systems. Both aortic rings and perfused kidneys obtained from male Wistar rats treated with lipopolysaccharide (LPS; 10 mg/kg, i.p.) were evaluated for their reactivity to vasopressin (AVP), 6 and 24 h after LPS injection (LPS 6 and LPS 24 h groups, respectively). AVP‐induced contraction was reduced by 30‐80% in aortic rings from LPS 6 and 24 h groups, while perfused kidneys showed enhanced responses to AVP. For instance, AVP (10 pmol) increased the renal perfusion pressure by 27.5 ± 4.7, 95 ± 12.8, and 150.6 ± 11.4 mm Hg in control, LPS 6 and LPS 24 h groups, respectively. Western blotting analysis revealed increased levels of phosphorylated MYPT1 in kidneys, but not in aortas from LPS 6 and 24 h rats. Our results demonstrate that vascular systems may present different profiles of responses to vasoconstrictors during endotoxemia. At least for AVP, it appears to involve a differential regulation of intracellular mechanisms responsible for the control of vascular contractility, such as the myosin phosphatase.Grant Funding Source: Supported by CNPq, Brazil; and FAPESC, Brazil.
Treatment resistance in prostate cancer: Rationale of combination therapy (85.2)
Authors: Zoubeidi Amina 
Published: June 2021

Despite advances in targeting the androgen receptor in prostate cancer patients which have led to unprecedented improvements in both overall survival and disease free, challenges still remain. Recently FDA approved second generation anti‐androgen Enzalutamide (ENZ) has limited efficacy in a substantial percentage of men and even those showing dramatic responses still develop resistance. These clinical results underscore the importance of understanding the mechanisms of resistance to ENZ. As seen in patients, we found that the resistance also occurs in our preclinical LNCaP xenograft model; the maximum androgen blockade (castration plus ENZ) leads to cancer recurrence in 80% of the ENZ treated tumors while only 20% responded to treatment. Targeting the AR in ENZ resistant tumors with a 3rd generation AR inhibitor was short lived. These data highlight that unexplored signalling pathways drive treatment resistance beyond classical AR reactivation underscore the need of more effective therapies. Using unbiased approaches of gene profiling and sequencing, we found that resistance is heterogeneous and displays cell plasticity indicating the existence of the epithelial cells driven by AR, the emergence of cancer stem cells (CSCs) and cells that may have progressed through an epithelial‐to mesenchymal transition (EMT). We will discuss the involvement of oncogenic and survival pathways driving the resistance as well as the rational of co‐targeting therapy to enhance the efficacy of Enzalutamide for better and long anti‐cancer response.This work is supported by Prostate Cancer Canada Movember Team grant, Prostate Cancer Foundation USA and NCI SPORE Pilot grant
Ramipril protects the endothelium from hyperglycaemia‐induced dysfunction through AMPK and HO‐1 activation (851.10)
Authors: Tian Shiliu , Liu Yu , Ge Xinfa , Wu Ke , Yang Huabing 
Published: June 2021

Aims: To investigate the effects of ramipril (RPL), an angiotensin‐converting enzyme (ACE) inhibitor, on endothelial dysfunction associated with diabetes mellitus using cultured human aortic endothelial cells (HAECs) and a type 2 diabetic animal model.Methods and results: The effect of RPL on vasodilatory function in fat‐fed, streptozotocin‐treated rats was assessed. RPL treatment for 16 weeks starting at 8 weeks attenuated the decrease in endothelium‐dependent vasodilation in diabetic rats. RPL treatment also reduced serum advanced glycation end products (AGEs) concentration. Exposure of HAECs to high concentrations of glucose induced prolonged oxidative stress, apoptosis and accumulation of AGEs in HAEC. These effects were abolished by RPL incubation. In addition, RPL increased nuclear factor erythroid 2‐related factor‐2 (Nrf‐2) activation in a CaMKKβ/AMPK pathway dependent manner. RPL treatment increased the expression of the Nrf‐2‐regulated antioxidant enzyme, heme oxygenase‐1 (HO‐1).Conclusion: Ramipril ameliorates endothelial dysfunction in diabetes by enhancing vasodilation in addition to reducing oxidative stress. These effects are mediated by ramipril activation of CaMKK‐β, which in turn activates the AMPK‐Nrf‐2‐HO‐1 pathway for enhanced endothelial function.Grant Funding Source: Supported by Shanghai Key Laboratory of Human Performance(SUS) 11DZ2261100
Caveolin‐1 nitrosation and degradation results in eNOS uncoupling, endothelial dysfunction, and nitrate tolerance (851.18)
Authors: Mao Mao , Varadarajan Sudhahar , Fukai Tohru , Bakhshi Farnaz , Chernaya Olga , Dudley Samuel , Minshall Rich , Bonini Marcelo 
Published: June 2021

Prolonged treatment with nitroglycerin (GTN) has been shown to induce nitrate tolerance and cross‐tolerance. However, much of the mechanism of how GTN leads to tolerance remains unknown. Recent evidence indicates that GTN induced endothelial‐dependent vasodilation requires endothelial nitric oxide synthase (eNOS) activation. Thus, we hypothesized that eNOS dysfunction as a result of continuous GTN exposure might underlie nitrate tolerance. Caveolin‐1 (CAV‐1) is known to interact with eNOS and regulate eNOS function. Loss of caveolin‐1 results in eNOS hyper‐activation which evolves into eNOS dysfunction and converts the enzyme into a source of oxidative stress. In this study we investigated the roles of CAV‐1 and eNOS in tolerance. We report that when endothelial cells are continuously exposed to GTN, eNOS becomes a source of peroxynitrite secondary to CAV‐1 depletion. We demonstrate that CAV‐1 is nitrosated and degraded in both GTN treated endothelial cells and animal tissues which parallels a marked increase in eNOS phosphorylation (Ser 1177) and accumulation of monomeric eNOS. We also demonstrate in endothelial cells that although CAV‐1 mRNA level is not changed, ubiquitination on the protein is increased with GTN, and that treatment of the proteasome inhibitor MG132 partially restores CAV‐1 levels which indicates that GTN‐induced CAV‐1 loss is due to post‐translational modification‐dependent degradation. We also confirmed that eNOS is dysfunctional in the CAV‐1 knockout mouse, which is naturally tolerant to pharmacologically relevant doses of GTN. Moreover, we show that elevated production of peroxynitrite from dysregulated eNOS is abolished upon rescue of CAV‐1 expression suggesting that eNOS may be uncoupled in the absence of CAV‐1. Taken together, these results imply that GTN‐induced CAV‐1 depletion and subsequent eNOS dysfunction can give rise to nitrate tolerance.Grant Funding Source: Supported by American Heart Association (AHA)
Endothelium‐independent vascular relaxation induced by whey protein: role of protein hydrolyzes by pepsin (851.19)
Authors: da Silva Gabriel , Guarido Karla , Mellinger‐Silva Caroline , da Silva‐Santos José Eduardo 
Published: June 2021

The effects of the whey protein (WP) on the vascular system have been investigated in both animals and humans, but both active substances and mechanisms involved in its effects remain unclear. In this study, samples of WP subjected to hydrolysis by pepsine for 1 min (PP0) 1, 2, 3, 4 or 5 h (PP1, PP2, PP3, PP4 and PP5, respectively), as well as the crude WP (PPCr), had their ability to cause vascular relaxation investigated. Addition of all fractions of WP (0.3, 1, 3, 5 and 10 mg/ml) in phenylephrine‐contracted aortic rings induced a concentration‐dependent relaxation in both endothelium‐intact and endothelium‐denuded vessels. Interestingly, the maximum relaxation induced by WP fractions increased from 21.9 ± 5.4, 23.1 ± 11, 33.9 ± 9.8% for PPCr, PP0, PP1 and PP2, to 77.1 ± 4.8, 77.7 ± 3.9 and 79.7 ± 3.4 for PP3, PP4 and PP5, respectively. Importantly, none of the fractions tested impaired the vascular responses to vasoactive agents after removed from the baths. This study demonstrates that hydrolyses by pepsin, one of the main proteolytic enzymes found in the digestive system, is crucial for the ability of the whey protein to cause in vitro vascular relaxation.Grant Funding Source: Supported by CNPq, Brazil; Embrapa, Brazil; and FAPERJ, Brazil.
Erectile dysfunction associated with aging in transgenic sickle cell disease mice (851.4)
Authors: Franco‐Penteado Carla , Silva Fabio , Priviero Fernanda , Antunes Edson , Costa Fernando , Claudino Mário 
Published: June 2021

Priapism is defined as prolonged and persistent penile erection, unassociated with sexual interest or stimulation and increase the development of erectile dysfunction(ED), and is a complication associated with sickle cell disease (SCD). Moreover, prevalence of ED associated with priapism increases progressively with aging, but, understanding of stages involved is still poorly investigated. Thus, we evaluate the muscle reactivity of isolated corpus cavernosum (CC) of SCD old mice. The animals were divided in control (CT; 3 month), control old (CTO; 1.2 year) and SCD old (SSO; 1.2 year) groups. Concentration‐response curves to acethylcholine (ACh), sodium nitroprusside (SNP) and phenylephrine (PE) were obtained in CC mice. Nitrergic and neurogenic responses induced by electrical‐field stimulation (EFS) were also obtained in all groups. The potency (pEC50) to ACh did not change in all group, but, the maximal response (Emax) was decrease in SSO (Emax: 20 ± 9%, P<0.05) compared to CT and CTO (Emax: 95 ± 6%; 68 ± 12%, respect.). The pEC50 of SNP was decrease in SSO (5.6 ± 0,2; P<0.05) compared to CT (6.4 ± 0.2) and CTO (6.6 ± 0.1), but, the Emax did not change in all group. However, nitrergic response induced by EFS was increase in SSO mice in the higher frequencies (8‐32Hz; P<0.05) compared to CT and CTO. The pEC50 of PE did not change in SSO compared to CT and CTO, but, the Emax was increase in SSO (1.6 ± 0.1mN, P<0.05) compared to CT and CTO (Emax: 1.0 ± 0.1; 1.4 ± 0,2mN, respect.). Neurogenic contractile response was significantly decrease in the higher frequency (32 Hz) compared to CT and CTO. Thus, SSO mice exhibit an impaired ACh‐, SNP‐induced relaxant response and an increase of contractile mechanism in the CC mice featuring the ED associated with priapism in SCD.Grant Funding Source: FAPESP/CNPq
Impact of central blood volume on the cardiovascular response to isometric handgrip exercise (852.5)
Authors: Lalande Sophie , Barron Carly , Shoemaker J 
Published: June 2021

The objective of this study was to determine the effect of central blood volume (CBV) manipulation on the cardiovascular response to ischemic isometric handgrip exercise. Fifteen young individuals (8 males, age:25±3 years) performed an handgrip protocol consisting of 3 min of ischemia followed by 2 min of ischemic handgrip exercise at 35% of maximum voluntary contraction during either a 10 degree head‐down tilt (HDT) (increased CBV) or lower body negative pressure at ‐5 mmHg (LBNP) (decreased CBV). Mean arterial pressure (MAP), heart rate (HR) and cardiac output were assessed by finger plethysmography and central venous pressure (CVP) was estimated from the antecubital venous pressure. CVP was greater during HDT than LBNP at baseline (8.8±2.0 vs. 6.9±2.1 mmHg, p<0.01) and throughout the handgrip protocol. MAP, HR and cardiac output increased from ischemia to handgrip exercise during both LBNP and HDT. Changes in MAP from ischemia to handgrip exercise were greater during LBNP than HDT (20±6 vs. 16±7 mmHg, p=0.02). Changes in MAP were correlated to HR (r=0.40, p=0.04) and stroke volume index (r=‐0.51, p<0.01). Therefore, MAP response to isometric handgrip exercise during both LBNP and HDT was mediated by changes in cardiac function.Grant Funding Source: Supported by NSERC and CIHR.
Role of IL‐6 in a novel murine model of transient ischemic attack (853.1)
Authors: Tang Ya Hui , Vital Shanatel , Granger D. Neil 
Published: June 2021

TIA is a precursor event in 7‐40% of patients who suffer from an ischemic stroke. This study involves the development of a murine model of TIA and explores the mechanism that accounts for the increased vulnerability of cerebral arterioles to thrombus development after TIA. TIA was simulated by brief (2.5 ‐ 10 min) occlusion of the middle cerebral artery. Thrombus formation in cerebral arterioles (induced by light/dye photoactivation of FITC‐dextran) was evaluated 1 ‐ 28 days after the TIA. Thrombosis was quantified using time of onset of platelet aggregation on the vessel wall and the time to complete flow cessation. While the brief period of TIA was not associated with neurological deficits or brain infarction (evaluated after 1 day), it yielded a pronounced and prolonged (up to 28 days) acceleration of thrombus formation, compared to control (sham) mice. Either immunoblockade of the interleukin‐6 (IL‐6) receptor or genetic deficiency of IL‐6, but not IL‐6‐/‐ bone marrow chimeras, signficantly protected against the TIA induced enhancement of thrombosis. Our findings indicate that the increased vulnerability of the cerebral vasculature to thrombus development after TIA can be recapitulated in a murine model, and that IL‐6, likely derived from brain tissue, rather than circulating immune cells, is an important mediator of, and possible therapeutic target for, TIA‐induced thrombogenesis.Grant Funding Source: HL26441
Mice with MC4R rescued in forebrain neurons exhibit increased peripheral glucose uptake after acute central leptin infusion (854.3)
Authors: da Silva Alexandre , Pinkerton Mark , do Carmo Jussara 
Published: June 2021

We previously showed that an intact brain melanocortin system (specifically, melanocortin 4 receptors MC4R)) is required for leptin to exert its antidiabetic action. However, the brain regions where MC4R activation contributes to the powerful effects of the leptin‐MC4R axis to improve glucose handling in peripheral tissues are still unknown. We examined whether rescue of MC4R specifically in forebrain neurons (MC4R/CamK2‐Cre mice, n=7) of whole‐body MC4R deficient mice (LoxTB‐MC4R mice, n=5) is associated with increased peripheral glucose uptake after acute intracerebroventricular (ICV) leptin injection. Wild‐type (WT) littermates were used as controls (n=4). Mice were implanted with ICV cannula into the lateral ventricle and after 10 days of recovery, leptin (2 μg/2 μl) was injected 15 minutes before mice received a bolus dose of [14C] 2‐deoxyglucose (2‐DG, 12 μCi, ip). Blood samples were collected at 10, 20, 30 and 40 min post 2‐DG injection and tissues were harvested for 2‐DG uptake. LoxTB‐MC4R mice were heavier (42±1 vs 36±3 and 27±2 g) with slightly higher blood glucose levels (110±5 vs 92±8 and 95±9 mg/ml) compared to MC4R/Camk2‐Cre and WT mice, respectively. After ICV leptin injection glucose uptake by the brain, brown adipose tissue, skeletal muscle and white adipose tissue was significantly higher in MC4R/Camk2‐Cre and WT mice (69±4 and 81±2; 118±5 and 155±17; 23±5 and 43±2; 14±2 and 25±8 μmol/100 mg tissue/min) compared to loxTB‐MC4R mice (44±12, 86±5, 16±3 and 9±3 μmol/100 mg tissue/min).These results suggest that MC4R in forebrain neurons may play an important role in contributing to the acute effects of leptin on peripheral glucose homeostasis. (NHLBI‐PO1HL51971, NIGMS P20GM104357 and AHA SDG5680016)Grant Funding Source: Supported by NIH: NHLBI‐PO1HL51971 and NIGMS P20GM104357 and by AHA: SDG5680016
Deficiency of c‐Jun‐N‐terminal kinase prevents angiotensin II‐induced inward remodeling but not hypertrophy in cerebral arterioles (856.13)
Authors: Umesalma Shaikamjad , Gerhold Thomas , Baumbach Gary 
Published: June 2021

Angiotensin II (Ang II) is an important determinant of inward remodeling in cerebral arterioles. We examined the effect of c‐Jun‐N‐terminal kinase (JNK) deficiency on structural alterations in cerebral arterioles induced by Ang II. Three month old JNK1‐deficient (JNK1‐/‐) and wild‐type (WT, C57BL/6J) mice were administered Ang II (1000 ng/kg/day) or saline for 4 weeks via osmotic minipumps. Systolic arterial pressure (SAP) was measured by a tail‐cuff method. External diameter (ED) of maximally dilated cerebral arterioles was measured in vivo through an open cranial window in anesthetized mice. Cross‐sectional area (CSA) of the vessel wall was measured histologically. Infusion of Ang II significantly increased SAP in both WT (148±7 vs 120±4 [saline infused] mmHg, P<0.05) and JNK1‐/‐ (148±3 vs 118±5 mmHg, P<0.05) mice; reduced cerebral arteriolar ED in WT (57±4 vs 68±3 μm, P<0.05), but not in JNK1‐/‐ mice (65±4 vs 66±4 μm, P<0.05); and increased CSA of the arteriolar wall in JNK1‐/‐ (501±41 vs 388±49 μm2, P<0.05), as well as WT (519±74 vs 393±30 μm2, P<0.05). In conclusion, our findings suggest that JNK1 may play an important role in Ang II‐induced inward remodeling, but not hypertrophy, in cerebral arterioles.Grant Funding Source: NIH
Effects of treatment with aliskiren and l‐arginine in baroreflex sensitivity in renovascular hypertensive rats (856.5)
Authors: Mengal Vinícius , Silva Paulo , Tiradentes Renata , Santuzzi Cintia , Gouvea Sonia , Abreu Glaucia 
Published: June 2021

In some pathological conditions such as hypertension, there is an impairment in the autonomic control of blood pressure resulting in changes in baroreflex sensitivity. In this context, this work aims to elucidate the benefits of the combination of aliskiren and L‐arginine in the control of blood pressure and the restoration of reduced baroreflex sensitivity in renovascular hypertension. Renovascular hypertension (2K1C) was produced in Male Wistar rats (140‐160 g). Seven days after was performed by plethysmography to measure systolic blood pressure. The rats were divided in groups: Sham (6), 2K1C (7), 2K1C aliskiren 50 mg/kg (8), 2K1C L‐arg 300 mg/kg (8) and 2K1C ALK + L‐arg (7). The treatment was performed for 21 days by gavage. The animals were anesthetized and fitted with femoral venous and arterial catheters for drug injection and arterial pressure recordings. We performed the direct recording of blood pressure and heart rate compared to variations in blood pressure induced with vasoactive drugs phenylephrine and sodium nitroprusside before and after administration of superoxide dismutase (SOD) mimetic tempol. At the end of the protocol, the expression of GPphox and SOD in aorta were analyzed by Western blotting. Statistical analysis was determined using 1‐way ANOVA and Tukey test. Values are expressed as mean ± SEM and the significance of P <0.05. Only the treatment with the combination of ALK + L‐arg was able to normalize systolic blood pressure. The 2K1C showed a reduction in baroreflex sensitivity after intravenous bolus of phenylephrine when compared to sham group as well as a reduction when administered in this modulation sodium nitroprusside. This reduction was restored in 2K1C after treatment with aliskiren and with the combination of aliskiren and L‐arginine in both intravenous administrations. The combination of ALK and L‐ARG was able to reduce the arterial pressure levels and increase in baroreflex sensitivity. These effects could be related a reduction in oxidative stress.Grant Funding Source: CNPq
Two‐photon microscopy enables non‐invasive, in vivo, longitudinal study of arterial Ca2+ and diameter in optical biosensor mice during the development of hypertension (856.7)
Authors: Mauban Joseph , Fairfax Seth , Zhang Jin , Rizzo Mark , Wier W. 
Published: June 2021

Here, we report that use of two‐photon microscopy of ear arteries in exMLCK biosensor mice enables non‐invasive, in vivo, serial examination of vascular smooth muscle Ca2+ during the development of hypertension. ExMLCK mice express a FRET‐type biosensor of Ca2+/Calmodulin based on smooth muscle myosin light chain kinase (MLCK) and its ratiometric properties permit direct quantification of intracellular Ca2+ concentration. Anesthetized biosensor mice were positioned on a custom platform, facilitating imaging of selected arterial branches within the intact depilated ear, and studied before and during chronic infusion of angiotensin‐II (ANGII; 800 µg/g/day) via mini‐osmotic pump. Acute responsiveness to i.p. phenylephrine (PE; 30µg/g) was determined in a separate group of mice equipped with arterial blood pressure radio telemetry. Eight days of chronic ANGII increased intracellular Ca2+ from 294±47nM to 501±92nM (P<0.05) and decreased artery diameter by ‐14±2% (P<0.05). Acute PE induced robust vasomotion and 2‐3 fold oscillations in spatially averaged Ca2+. In summary, this new methodology permits for the first time the simultaneous study of Ca2+ signaling, structural remodeling and vascular reactivity in the intact living mouse during hypertension development.Grant Funding Source: Supported by NHLBI RO1091969, RO1HL107654, RO1DK077140, and T32HL072751.