Endothelial specific isoform of type XVIII collagen (COL-18N): A marker of vascular integrity in haemophilic arthropathy.

BACKGROUND: Haemophilic arthropathy (HA) is a major complication in haemophilia. Collagens IV, XV and XVIII are responsible for maintaining the integrity of the vessel wall in the joint. Following joint remodelling and damage, the short isoform of collagen type XVIII (COL-18N) is degraded, releasing measurable fragments. Our goal was to quantify the specific isoform COL-18N in haemophilia A patients and to assess its relation to the clinical and radiological data as well as haemophilia joint health score (HJHS), functional independence score for haemophilia (FISH), and haemophilia quality of life (Haemo-Qol). METHODS: This cross-sectional study included 50 haemophilia A patients recruited from the Paediatric Haematology and Oncology unit, Ain Shams University, Cairo, Egypt. Quantification of COL-18N was done by ELISA. Assessment of joint state clinically using FISH and HJH scores and radiologically by X-rays and ultrasound. RESULTS: Haemophilia A patients had significantly higher median COL-18N levels compared to the control group. Inhibitor positive and negative haemophilia A patients as well as those on non-steroidal anti-inflammatory drug and those not had comparable COL-18N levels. Patients with ≥2 target joints had significantly higher COL-18N level compared to those with one or those without target joints. There were significant positive correlations between COL-18N level and the total HJHS, Haemo-Qol, the HEAD-US score and annual bleeding rate. CONCLUSION: Our results demonstrated a high level of COL-18N in haemophilia A patients and argued its benefit as a potential marker for monitoring the development of haemophilic arthropathy and tailoring the optimal treatment to prevent further joint damage.

Acute high-intensity interval exercise versus moderate-intensity continuous exercise in heated water-based on hemodynamic, cardiac autonomic, and vascular responses in older individuals with hypertension.

OBJECTIVES: This crossover study design aimed to assess hemodynamic, cardiac autonomic, and vascular responses to high-intensity interval (HIIE) vs moderate-intensity continuous exercise (MICE) in older individuals with hypertension. METHODS: Twenty (67 ± 7 y) older individuals with hypertension were randomly assigned to perform HIIE, MICE, or control (CON) sessions in the heated swimming pool (30-32°C). Blood pressure (BP), arterial stiffness, endothelial reactivity, and heart rate variability (HRV) were measured pre, post, and 45 min (recovery) after each intervention followed by 24-h ambulatory BP and HRV. RESULTS: One single aerobic exercise session was not effective to provoke post-exercise hypotension and vascular improvements. HIIE was superior to MICE and CON to increasing parasympathetic modulation at post and recovery. Exercise sessions showed to disturb the autonomic system at nighttime compared to CON. CONCLUSIONS: These results may have important implications in water-based therapy and the elderly with hypertension.

A single-cell atlas of the normal and malformed human brain vasculature.

Cerebrovascular diseases are a leading cause of death and neurologic disability. Further understanding of disease mechanisms and therapeutic strategies requires a deeper knowledge of cerebrovascular cells in humans. We profiled transcriptomes of 181,388 cells to define a cell atlas of the adult human cerebrovasculature, including endothelial cell molecular signatures with arteriovenous segmentation and expanded perivascular cell diversity. By leveraging this reference, we investigated cellular and molecular perturbations in brain arteriovenous malformations, which are a leading cause of stroke in young people, and identified pathologic endothelial transformations with abnormal vascular patterning and the ontology of vascularly derived inflammation. We illustrate the interplay between vascular and immune cells that contributes to brain hemorrhage and catalog opportunities for targeting angiogenic and inflammatory programs in vascular malformations.

Effect of live-fire training on ventricular-vascular coupling.

INTRODUCTION: Cardiovascular events are a leading cause of firefighter duty-related death, with the greatest risk occurring during or shortly after fire suppression activity. Increased cardiovascular risk potentially manifests from detrimental changes in ventricular function, vascular load, and their interaction, described as ventricular-vascular coupling. PURPOSE: To determine the effect of live-fire training on ventricular-vascular coupling. METHODS: Sixty-eight male (28 [Formula: see text] 7 years, 26.9 [Formula: see text] 3.9 kg/m2) and fifteen female (36 [Formula: see text] 8 years, 24.3 [Formula: see text] 3.9 kg/m2) firefighters completed hemodynamic and cardiac measures before and after 3 h of intermittent live-fire training. Left ventricular function was assessed as ejection fraction (EF) and ventricular elastance (ELV: end systolic pressure [ESP]/end systolic volume) via echocardiography and applanation tonometry-estimated ESP. Vascular load was assessed as arterial elastance (EA: ESP/stroke volume [SV]). Ventricular-vascular coupling (VVC) was quantified as the ratio of EA to ELV and indexed to body surface area (EAI, ELVI). RESULTS: Following firefighting EF decreased (p < 0.01) with no change in ELVI (p = 0.34). SV decreased (p < 0.01) with no change in ESP (p = 0.09), driving a significant increase in EAI (p < 0.01). These changes resulted in a significant increase in the VVC ratio (p < 0.01). CONCLUSION: The findings suggest that firefighting does not alter ventricular elastance but increases arterial elastance in healthy firefighters, resulting in a mismatch between ventricular and vascular systems. This increase in ventricular-vascular coupling ratio and concomitant reduction in ventricular systolic function may contribute to increased cardiovascular risk following live firefighting.

The relationship between telomere length and putative markers of vascular ageing: A systematic review and meta-analysis.

Accelerated biological aging contributes to the evolution of cardiovascular disease. However, its influence on subclinical organ damage remains unclear. Leukocyte telomere length (LTL) is emerging as a marker of biological cardiovascular aging. We performed a systematic review and meta-analysis to assess the association between LTL and measures of end-organ damage. PubMed, Medline, Embase, Cinahl Plus, ClinicalTrials.gov, and grey literature databases were searched for studies that assessed the association of LTL with arterial pulse wave velocity (aPWV), carotid intima-media thickness (cIMT), left ventricular mass (LVM or LVMI), renal outcomes, coronary artery calcium (CAC) and presence of carotid plaques. In a sample of 7256 patients, we found that cIMT (pooled correlation coefficient (r) = -0.249; 95 %CI -0.37, -0.128) and aPWV (pooled r = -0.194; 95 % CI -0.290, -0.100) inversely correlate with LTL. Compared to aPWV, cIMT had a stronger correlation with LTL. Patients without carotid plaques had longer telomeres than patients with carotid plaques. Quantitative analyses documented LTL association with renal outcomes and CAC, but not with LVM/LVMI. Among measures of end-organ damage, cIMT and aPWV provide the most accurate information on the contribution of biological aging to the process of vascular remodeling/damage.

Updated perspectives on vascular cell specification and pluripotent stem cell-derived vascular organoids for studying vasculopathies.

Vasculopathy is a pathological process occurring in the blood vessel wall, which could affect the haemostasis and physiological functions of all the vital tissues/organs and is one of the main underlying causes for a variety of human diseases including cardiovascular diseases. Current pharmacological interventions aiming to either delay or stop progression of vasculopathies are suboptimal, thus searching novel, targeted, risk-reducing therapeutic agents, or vascular grafts with full regenerative potential for patients with vascular abnormalities are urgently needed. Since first reported, pluripotent stem cells (PSCs), particularly human-induced PSCs, have open new avenue in all research disciplines including cardiovascular regenerative medicine and disease remodelling. Assisting with recent technological breakthroughs in tissue engineering, in vitro construction of tissue organoid made a tremendous stride in the past decade. In this review, we provide an update of the main signal pathways involved in vascular cell differentiation from human PSCs and an extensive overview of PSC-derived tissue organoids, highlighting the most recent discoveries in the field of blood vessel organoids as well as vascularization of other complex tissue organoids, with the aim of discussing the key cellular and molecular players in generating vascular organoids.

Retinal blood vessel calibre and vascular ageing in a general Spanish population: A EVA study.

INTRODUCTION: The aim of this work was to analyse the association of the retinal arteriolar calibre and the arteriole/venule index (AV index) with vascular ageing in a general population without previous cardiovascular disease. MATERIALS AND METHODS: Descriptive cross-sectional study. A total of 482 individuals without cardiovascular disease (mean age: 55.6 ± 14.2 years) were selected by random sampling, stratified by age and sex. The retinal arteriolar calibre was measured using digital fundus images of the back of the eye captured with a validated, semiautomatized and computer-assisted software (Index calculator). Vascular ageing was defined using three criteria based on the values of: (1) Carotid-femoral Pulse Wave Velocity (cfPWV), (2) Brachial-ankle Pulse Wave Velocity (baPWV) and (3) Carotid Intima-Media Thickness. RESULTS: The AV index and arteriolar calibre show a negative correlation with age, arterial pressure, cardiovascular risk and parameters of vascular structure and function (p < 0.001 in all cases). We found lower mean values of the AV index and arteriolar calibre in the individuals with early vascular ageing compared to those with healthy vascular ageing. AV index was negatively correlated with cfPWV ((ß=-2.9; 95% CI (-4.7; -1.1)), baPWV ((ß=-3.2; 95% CI (-5.4; -0.9)) and vascular ageing index ((ß=-1.7; 95% CI (-2.7; -0.7)). Arteriolar calibre showed a negative correlation with baPWV (ß=-0.1; 95% CI (-0.2; -0.1)). In the logistic regression analysis, lower values of AV index ((OR=0.01; 95% CI (0.01-0.10), OR=0.03; 95% CI (0.01-0.11) and OR=0.09; 95% CI (0.01-0.67)) were associated with EVA defined with cfPWV, baPWV and vascular ageing index respectively, and lower values of arteriolar calibre ((OR=0.71; 95% CI (0.55-0.91)) were associated with EVA defined with vascular ageing index. CONCLUSIONS: Lower values of AV index and retinal arteriolar calibre were associated with vascular ageing in a general Spanish population without previous cardiovascular disease.

Vascular Dysfunction in Preeclampsia.

Preeclampsia is a life-threatening pregnancy-associated cardiovascular disorder characterized by hypertension and proteinuria at 20 weeks of gestation. Though its exact underlying cause is not precisely defined and likely heterogenous, a plethora of research indicates that in some women with preeclampsia, both maternal and placental vascular dysfunction plays a role in the pathogenesis and can persist into the postpartum period. Potential abnormalities include impaired placentation, incomplete spiral artery remodeling, and endothelial damage, which are further propagated by immune factors, mitochondrial stress, and an imbalance of pro- and antiangiogenic substances. While the field has progressed, current gaps in knowledge include detailed initial molecular mechanisms and effective treatment options. Newfound evidence indicates that vasopressin is an early mediator and biomarker of the disorder, and promising future therapeutic avenues include mitigating mitochondrial dysfunction, excess oxidative stress, and the resulting inflammatory state. In this review, we provide a detailed overview of vascular defects present during preeclampsia and connect well-established notions to newer discoveries at the molecular, cellular, and whole-organism levels.

Perivascular Adipose Tissue in Vascular Function: Does Locally Synthesized Angiotensinogen Play a Role?

ABSTRACT: In recent years, perivascular adipose tissue (PVAT) research has gained special attention in an effort to understand its involvement in vascular function. PVAT is recognized as an important endocrine organ that secretes procontractile and anticontractile factors, including components of the renin-angiotensin-aldosterone system, particularly angiotensinogen (AGT). This review critically addresses the occurrence of AGT in PVAT, its release into the blood stream, and its contribution to the generation and effects of angiotensins (notably angiotensin-(1-7) and angiotensin II) in the vascular wall. It describes that the introduction of transgenic animals, expressing AGT at 0, 1, or more specific location(s), combined with the careful measurement of angiotensins, has revealed that the assumption that PVAT independently generates angiotensins from locally synthesized AGT is incorrect. Indeed, selective deletion of AGT from adipocytes did not lower circulating AGT, neither under a control diet nor under a high-fat diet, and only liver-specific AGT deletion resulted in the disappearance of AGT from blood plasma and adipose tissue. An entirely novel scenario therefore develops, supporting local angiotensin generation in PVAT that depends on the uptake of both AGT and renin from blood, in addition to the possibility that circulating angiotensins exert vascular effects. The review ends with a summary of where we stand now and recommendations for future research.

COVID-19: Cardio-pulmonary and Vascular Manifestations.

The COVID-19 pandemic is still threatening us, our patients, and the global health care system. Since the first outbreak at the end of 2019 in China, it became rapidly clear that a new variant of a SARS virus, SARS-CoV-2, is threatening our human society worldwide. Since then, the scientific community has accumulated an incredibly large amount of knowledge about the pathophysiology of this virus, primarily affecting the respiratory tract and, in severe cases, subsequently resulting in acute respiratory distress syndrome and multiple organ failure due to uncontrolled systemic inflammatory response syndrome.1 2.

Pulse sharpness as a quantitative index of vascular aging.

The aim of this study was to develop a robust algorithm to quantify pulse sharpness that can complement the limitations of radial augmentation index (rAIx) and explore the role of this quantitative sharpness index in reflecting vascular aging or arterial stiffness. The pulse sharpness index (PSI) was developed by combining the end point angle and virtual height, and 528 radial pulses were analyzed. The PSI could be uniformly applied to various waveform morphologies, even those with no or vague tidal waves, unlike the rAIx. Significant sex differences were identified in the rAIx and PSI (P < 0.01 for both), and significant age-dependent decreases in the PSI were observed (P < 0.01). In addition, the PSI and age were correlated (r = - 0.550) at least as strong as the rAIx and age (r = 0.532), and the PSI had a significant negative correlation with arterial stiffness (r = - 0.700). Furthermore, the multiple linear regression model for arterial stiffness using the PSI, age, sex and heart rate showed the excellent performance (cross-validated R2 = 0.701), and the PSI was found to have the greatest influence on arterial stiffness. This study confirmed that the PSI could be a quantitative index of vascular aging and has potential for use in inferring arterial stiffness with an advantage over the rAIx.

Rationale and design of the application value of Beijing Vascular Health Stratification (BVHS): predictive value of combined assessment of vascular structure and function for cardiovascular events in general Chinese population.

BACKGROUND: Vascular endothelial dysfunction, arteriosclerosis and atherosclerotic plaque are well-known risk factors for cardiovascular disease (CVD). Studies on vascular health markers have been well-established, however, there is still a lack of related research on combined vascular structure and function indicators. METHOD: Beijing vascular health stratification (BVHS) is an evaluation system aiming at vascular health, combined the endothelial function, arteriosclerosis, atherosclerotic plaque and vascular lumen stenosis to comprehensively assess the vascular health and grade it. This study will explore the predictive value of the combined evaluation of vascular structure and function for cardiovascular events and assess the predictive value of BVHS and compare it with the existing risk assessment systems. A total of 1500 subjects will be enrolled into the prospective cohort study from a community and will be followed up for at least 3 years from July 1, 2020 to June 30, 2023. Subjects aged 40 or above, without coronary heart disease, stroke or peripheral artery disease, with written informed consent will be included; subjects with end-stage hepatorenal diseases (uremia, renal failure, cirrhosis, liver failure), mental disorders or cognitive disorders, with any other factors that the researcher thinks are not suitable for the study will be excluded. Traditional cardiovascular risk factors will be collected as adjusted confounders. DISCUSSION: BVHS is a potential and scientific vascular health evaluation system. The study will be the first to grade vascular health by combing various vascular indicators and explore the prediction value and compare with other risk prediction system in general Chinese population. TRIAL REGISTRATION: The trial is registered on http://www.chictr.org.cn/ (ChiCTR2000034085).

Development of heart failure with preserved ejection fraction in type 2 diabetic mice is ameliorated by preserving vascular function.

AIMS: Heart failure with preserved ejection fraction (HFpEF) is associated with endothelial dysfunction and is frequent in people with type 2 diabetes mellitus. In diabetic patients, increased levels of the eicosanoid 12-hydroxyeicosatetraenoic acid (12-HETE) are linked to vascular dysfunction. Here, we aimed to identify the importance of 12-HETE in type 2 diabetic patients exhibiting diastolic dysfunction, and mice exhibiting HFpEF and whether targeting 12-HETE is a means to ameliorate HFpEF progression by improving vascular function in diabetes. MATERIAL AND METHODS: Subjects with diagnosed type 2 diabetes mellitus and reported diastolic dysfunction or healthy controls were recruited and 12(S)-HETE levels determined by ELISA. 12(S)-HETE levels were determined in type 2 diabetic, leptin receptor deficient mice (LepRdb/db) and HFpEF verified by echocardiography. Mitochondrial function, endothelial function and capillary density were assessed using Seahorse technique, pressure myography and immunohistochemistry in LepRdb/db or non-diabetic littermate controls. 12/15Lo generation was inhibited using ML351 and 12(S)-HETE action by using the V1-cal peptide. KEY FINDINGS: Endothelium-dependent vasodilation and mitochondrial functional capacity both improved in response to either application of ML351 or the V1-cal peptide. Correlating to improved vascular function, mice treated with either pharmacological agent exhibited improved diastolic filling and left ventricular relaxation that correlated with increased myocardial capillary density. SIGNIFICANCE: Our results suggest that 12-HETE may serve as a biomarker indicating endothelial dysfunction and the resulting cardiovascular consequences such as HFpEF in type 2 diabetic patients. Antagonizing 12-HETE is a potent means to causally control HFpEF development and progression in type 2 diabetes by preserving vascular function.

Vascular Function and Distribution of Adiponectin Isomers during Puberty in Children and Adolescents with Obesity.

INTRODUCTION: Youth with obesity have abnormal vascular function that relates to the anti-atherogenic adipose-derived hormone, adiponectin. The distribution of adiponectin isomers changes during normal puberty, but there are no data in relation to vascular function. We aimed to evaluate vascular function, adiponectin, and its isomers longitudinally in peri-pubertal youth with obesity and controls. METHODS: The study is a cohort longitudinal study involving 30 children and adolescents with obesity (body mass index [BMI] z-score 2.31 ± 0.24; age 12.8 ± 3 years, 17 male participants) and 28 age-/sex-matched healthy controls (12.8 ± 3 years, 14 male participants). Vascular function (flow-mediated dilatation [FMD], glyceryl trinitrate-mediated dilatation [GTN]), total adiponectin and isomers, and laboratory and clinical variables were assessed at 0, 18, and 36 months. RESULTS: FMD and GTN were stable during puberty in both groups, remaining consistently lower in obese children (p = 0.02, p < 0.001). The change in total (p = 0.02) and high-molecular weight (HMW) (p = 0.02) adiponectin differed between the groups: falling in controls by the end of puberty but not falling further during puberty in obesity. In obesity, impaired GTN was associated longitudinally with lower total (B = 7.85, p = 0.006) and HMW (B = 3.72, p = 0.03) adiponectin. In controls, more favourable GTN was longitudinally associated with a lower BMI z-score (B = -3.04, p = 0.027) and lower waist circumference (B = -0.35, p = 0.009). CONCLUSIONS: Vascular dysfunction and lower levels of adiponectin are associated in children and adolescents with obesity during puberty and do not deteriorate further. Healthy children's better vascular function, within the normal range, is associated with a lower BMI z-score and waist circumference.

The Vascular Circadian Clock in Chronic Kidney Disease.

Chronic kidney disease is associated with extremely high cardiovascular mortality. The circadian rhythms (CR) have an impact on vascular function. The disruption of CR causes serious health problems and contributes to the development of cardiovascular diseases. Uremia may affect the master pacemaker of CR in the hypothalamus. A molecular circadian clock is also expressed in peripheral tissues, including the vasculature, where it regulates the different aspects of both vascular physiology and pathophysiology. Here, we address the impact of CKD on the intrinsic circadian clock in the vasculature. The expression of the core circadian clock genes in the aorta is disrupted in CKD. We propose a novel concept of the disruption of the circadian clock system in the vasculature of importance for the pathology of the uremic vasculopathy.

Erythrocytes as a Model for Heavy Metal-Related Vascular Dysfunction: The Protective Effect of Dietary Components.

Heavy metals are toxic environmental pollutants associated with severe ecological and human health risks. Among them is mercury (Hg), widespread in air, soil, and water, due to its peculiar geo-biochemical cycle. The clinical consequences of Hg exposure include neurotoxicity and nephrotoxicity. Furthermore, increased risk for cardiovascular diseases is also reported due to a direct effect on cardiovascular tissues, including endothelial cells, recently identified as important targets for the harmful action of heavy metals. In this review, we will discuss the rationale for the potential use of erythrocytes as a surrogate model to study Hg-related toxicity on the cardiovascular system. The toxic effects of Hg on erythrocytes have been amply investigated in the last few years. Among the observed alterations, phosphatidylserine exposure has been proposed as an underlying mechanism responsible for Hg-induced increased proatherogenic and prothrombotic activity of these cells. Furthermore, following Hg-exposure, a decrease in NOS activity has also been reported, with consequent lowering of NO bioavailability, thus impairing endothelial function. An additional mechanism that may induce a decrease in NO availability is the generation of an oxidative microenvironment. Finally, considering that chronic Hg exposure mainly occurs through contaminated foods, the protective effect of dietary components is also discussed.

Flow field around bubbles on formation of air embolism in small vessels.

An air embolism is induced by intravascular bubbles that block the blood flow in vessels, which causes a high risk of pulmonary hypertension and myocardial and cerebral infarction. However, it is still unclear how a moving bubble is stopped in the blood flow to form an air embolism in small vessels. In this work, microfluidic experiments, in vivo and in vitro, are performed in small vessels, where bubbles are seen to deform and stop gradually in the flow. A clot is always found to originate at the tail of a moving bubble, which is attributed to the special flow field around the bubble. As the clot grows, it breaks the lubrication film between the bubble and the channel wall; thus, the friction force is increased to stop the bubble. This study illustrates the stopping process of elongated bubbles in small vessels and brings insight into the formation of air embolism.

Crosstalk of TLR4, vascular NADPH oxidase, and COVID-19 in diabetes: What are the potential implications?

Toll-like receptor 4 (TLR4) contributes to the pathophysiology of diabetes. This happens, at least in part, because TLR4 modulates the enzyme NADPH oxidase, a primary source of ROS in vascular structures. Increased oxidative stress disrupts key vascular signaling mechanisms and drives the progression of diabetes, elevating the likelihood of cardiovascular diseases. Recently, it has been shown that patients with diabetes are also at a higher risk of developing severe coronavirus disease 2019 (COVID-19). Given the importance of the interaction between TLR4 and NADPH oxidase to the disrupted diabetic vascular system, we put forward the hypothesis that TLR4-mediated NADPH oxidase-derived ROS might be a critical mechanism to help explain why this disparity appears in diabetic patients, but unfortunately, conclusive experimental evidence still lacks in the literature. Herein, we focus on discussing the pathological implications of this signaling communication in the diabetic vasculature and exploring this crosstalk in the context of diabetes-associated severe COVID-19.

[Is Neuron-Vascular Communication Disturbed in the Delayed Prenatal Brain Development of a Mouse Model of Down Syndrome?]

Developmental retardation of the brain with reduced cortical neurogenesis is observed in Ts1Cje mice, a model of Down syndrome (DS) as it is in people with DS; however, the mechanisms and the responsible gene(s) remain unknown. The goal of the present study is to establish a therapeutic approach for treating the delayed brain development in DS. To achieve this, we have utilized multiple OMICS analyses, including proteomics and transcriptomics, to uncover the molecular alterations in the brains of DS model mice. Furthermore, we have elucidated that a transcriptional factor, the Erg gene, which is coded in the trisomic region, contributed to reduced cortical neurogenesis in the embryo of a DS mouse model by a molecular genetic technique, the "in vivo gene subtraction method". In the current review, I will introduce our recent work, the identification of the gene responsible for delayed brain development in the DS mouse model and will discuss the possibility that blood vessel dysfunction may be associated with reduced embryonic neurogenesis in DS.

Inhibition of the norepinephrine transporter rescues vascular hyporeactivity to catecholamine in obstructive jaundice.

In patients with obstructive jaundice, the cardiovascular system exhibits hypotension and vascular hyporeactivity. Most norepinephrine is taken up through the neuronal norepinephrine transporter (NET), which is implicated in cardiovascular diseases. A previous study demonstrated that pharmacological NET inhibition could increase resting blood pressure. However, the role of NETs in vascular hyporeactivity induced by obstructive jaundice is poorly understood. This study used the NET inhibitor nisoxetine and a rat model of bile duct ligation (BDL) to investigate whether NET is associated with BDL-induced vascular hyporeactivity. Rats were injected with nisoxetine via the tail vein for 7 consecutive days after BDL. Samples of the superior cervical sympathetic ganglion (SCG) and thoracic aortic rings were processed for investigations. Our results showed that NET expression in the SCG was significantly increased after BDL. Nisoxetine prevented the augmentation of NET expression, increased α1-adrenoceptor activation, and enhanced the weakened contractile responses of thoracic aortic rings after BDL. Our study demonstrates that nisoxetine plays a protective role in BDL-induced vascular hyporeactivity through increased α1-adrenoceptor activation in rats.