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Background: Digoxin poisonings are relatively common and potentially fatal, requiring immediate therapeutic intervention, with special attention to the patient's hemodynamic status and the presence of electrocardiographic and electrolytic disturbances., Objective: To identify factors associated with seven-day and thirty-day mortality in digoxin poisoning., Design, Settings and Participants: A retrospective, observational, multicenter study was conducted across 15 Hospital Emergency Departments (HED) in Spain. All patients over 18 years of age who presented to participating HEDs from 2015 to 2021 were included. The inclusion criteria encompassed individuals meeting the criteria for digoxin poisoning, whether acute or chronic., Outcomes Measure and Analysis: To identify independent factors associated with 7-day and 30-day mortality, a multivariate analysis was conducted. This analysis included variables of clinical significance, as well as those exhibiting a trend (p < 0.1) or significance in the bivariate analysis., Main Findings: A total of 658 cases of digoxin poisoning were identified. Mortality rates were 4.5% (30 patients) at seven days and 11.1% (73 patients) at thirty days. Regarding 7-day mortality, the mean age of deceased patients was comparable to survivors (84.7 (8.9) vs 83.9 (7.9) years; p = ns). The multivariate analysis revealed that factors independently associated with 7-day mortality encompassed the extent of dependence assessed by the Barthel Index (BI 60-89 OR 0.28; 95% CI 0.10-0.77; p = 0.014 and BI>90 OR 0.22; 95% CI 0.08-0.63; p = 0.005), the identification of ventricular arrhythmias (OR 1.34; 95% CI 1.34-25.21; p = 0.019), and the presence of circulatory (OR 2.84; 95% CI 1.19-6.27; p = 0.019) and neurological manifestations (OR 2.67; 95% CI 1.13-6.27; p = 0.025). Factors independently associated with 30-day mortality encompassed extent of dependence (BI 60-89 OR 0.37; 95% CI 0.20-0.71; p = 0.003 and BI>90 OR 0.18; 95% CI 0.09-0.39; p < 0.001) and the identification of circulatory (OR 2.13; 95% CI 1.10-4.15; p = 0.025) and neurological manifestations (OR 2.39; 95% CI 1.25-3.89; p = 0.006)., Conclusions: The study identifies the degree of dependency assessed by the Barthel Index and the presence of cardiovascular and neurological symptoms as independent predictors of both 7-day and 30-day mortality. Additionally, the detection of ventricular arrhythmia is also an independent factor for 7-day mortality., Competing Interests: Declaration of competing interest The authors report no declarations of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: Digoxin toxicity accounts for a small percentage of poisonings attended by emergency departments. This study aimed to describe differences between acute and chronic digoxin toxicity and assess the use of digoxin-specific antibody fragments (digoxin-Fab) as an antidote., Material and Methods: Retrospective, observational, multicenter study in 15 hospital emergency departments in 8 Spanish autonomous communities in 7 years. We collected patient, clinical and treatment variables, and discharge destination. Patients were classified according to whether toxicity was acute or chronic and whether digoxin-Fab was administered or not., Results: Twenty-seven acute and 631 chronic digoxin poisonings were attended. The mean (SD) patient age was 83.9 (7.9) years, and 76.9% were women. Patients with acute toxicity were younger (80.0 [12] years) than those with chronic toxicity (84.1 [7.7] years) (P .038), and accidental poisoning was less common (in 85.2% vs 100% in chronic toxicity; P .001). Cases of acute toxicity were also more serious (Poison Severity Score (29.6% vs 12.5% in chronic toxicity; P .001). Thirty-four patients were treated with digoxin-Fab (5.4%). These patients were younger (78.7 [11.5] years vs 84.2 (7.6) years), their toxicity was more often acute (in 20.6% vs 3.2% in chronic toxicity), more had attempted suicide (8.8% vs 0.2% with chronic toxicity), and more had severe symptoms (50% vs 11.2%) (P .001, all comparisons). Hospital admission was required for 76.1%. Overall, mortality was 11.4%., Conclusion: Chronic toxicity accounts for most digoxin poisoning cases, and most patients are women. Acute toxicity is more serious. Patients who required digoxin-Fab have more severe poisoning. Such patients usually have acute toxicity, and attempted suicide is more often the reason for the emergency.

Bitter taste receptors (TAS2R) are found in numerous extra-oral tissues, including smooth muscle (SM) cells in both vascular and visceral tissues. Upon activation, TAS2R stimulate the relaxation of the SM. Nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) signaling pathway is involved in penile erection, and type 5 phosphodiesterase (PDE5) inhibitors, a cGMP-specific hydrolase are used as first-line treatments for erectile dysfunction (ED). Nevertheless, PDE5 inhibitors are ineffective in a considerable number of patients, prompting research into alternative pharmacological targets for ED. Since TAS2R agonists regulate SM contractility, this study investigates the role of TAS2Rs in rat corpus cavernosum (CC). We performed immunohistochemistry to detect TAS2R10, isometric force recordings for TAS2R agonists denatonium and chloroquine, the slow-release H 2 S donor GYY 4137, the NO donor SNAP, the β-adrenoceptor agonist isoproterenol and electrical field stimulation (EFS), as well as measurement of endogenous hydrogen sulfide (H 2 S) production. The immunofluorescence staining indicated that TAS2R10 was broadly expressed in the CC SM and to some extent in the nerve fibers. Denatonium, chloroquine, SNAP, and isoproterenol cause potent dose-dependent SM relaxations. H 2 S production was decreased by NO and H 2 S synthase inhibitors, while it was enhanced by denatonium. In addition, denatonium increased the relaxations induced by GYY 4137 and SNAP but failed to modify EFS- and isoproterenol-induced responses. These results suggest neuronal and SM TAS2R10 expression in the rat CC, where denatonium induces a strong SM relaxation per se and promotes the H 2 S- and NO-mediated inhibitory gaseous neurotransmission. Thus, TAS2R10 might represent a valuable therapeutic target in ED., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

K V 7 channels exert a pivotal role regulating vascular tone in several vascular beds. In this context, K V 7 channel agonists represent an attractive strategy for the treatment of pulmonary arterial hypertension (PAH). Therefore, in this study, we have explored the pulmonary vascular effects of the novel K V 7 channel agonist URO-K10. Consequently, the vasodilator and electrophysiological effects of URO-K10 were tested in rat and human pulmonary arteries (PA) and PA smooth muscle cells (PASMC) using myography and patch-clamp techniques. Protein expression was also determined by Western blot. Morpholino-induced knockdown of KCNE4 was assessed in isolated PA. PASMC proliferation was measured by BrdU incorporation assay. In summary, our data show that URO-K10 is a more effective relaxant of PA than the classical K V 7 activators retigabine and flupirtine. URO-K10 enhanced K V currents in PASMC and its electrophysiological and relaxant effects were inhibited by the K V 7 channel blocker XE991. The effects of URO-K10 were confirmed in human PA. URO-K10 also exhibited antiproliferative effects in human PASMC. Unlike retigabine and flupirtine, URO-K10-induced pulmonary vasodilation was not affected by morpholino-induced knockdown of the KCNE4 regulatory subunit. Noteworthy, the pulmonary vasodilator efficacy of this compound was considerably increased under conditions mimicking the ionic remodelling (as an in vitro model of PAH) and in PA from monocrotaline-induced pulmonary hypertensive rats. Taking all together, URO-K10 behaves as a KCNE4-independent K V 7 channel activator with much increased pulmonary vascular effects compared to classical K V 7 channel activators. Our study identifies a promising new drug in the context of PAH., Competing Interests: Declaration of Competing Interest None. The authors have reported that they have no relationships with industry relevant to the contents of this paper to disclose. The funders played no role in the study design; nor in the collection, analyses, interpretation of data, nor in the writing of the manuscript., (Copyright © 2023. Published by Elsevier Masson SAS.)

K V 1.5 channels are key players in the regulation of vascular tone and atrial excitability and their impairment is associated with cardiovascular diseases including pulmonary arterial hypertension (PAH) and atrial fibrillation (AF). Unfortunately, pharmacological strategies to improve K V 1.5 channel function are missing. Herein, we aimed to study whether the chaperone sigma-1 receptor (S1R) is able to regulate these channels and represent a new strategy to enhance their function. By using different electrophysiological and molecular techniques in X. laevis oocytes and HEK293 cells, we demonstrate that S1R physically interacts with K V 1.5 channels and regulate their expression and function. S1R induced a bimodal regulation of K V 1.5 channel expression/activity, increasing it at low concentrations and decreasing it at high concentrations. Of note, S1R agonists (PRE084 and SKF10047) increased, whereas the S1R antagonist BD1047 decreased, K V 1.5 expression and activity. Moreover, PRE084 markedly increased K V 1.5 currents in pulmonary artery smooth muscle cells and attenuated vasoconstriction and proliferation in pulmonary arteries. We also show that both K V 1.5 channels and S1R, at mRNA and protein levels, are clearly downregulated in samples from PAH and AF patients. Moreover, the expression of both genes showed a positive correlation. Finally, the ability of PRE084 to increase K V 1.5 function was preserved under sustained hypoxic conditions, as an in vitro PAH model. Our study provides insight into the key role of S1R in modulating the expression and activity of K V 1.5 channels and highlights the potential role of this chaperone as a novel pharmacological target for pathological conditions associated with K V 1.5 channel dysfunction., Competing Interests: Conflict of interest None., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Aims: Nitric oxide (NO) and hydrogen sulfide (H 2 S) are involved in nerve-mediated corpus cavernosum (CC) relaxation. Expression of phosphodiesterase type 5 (PDE5) and type 4 (PDE4), cyclic guanosine monophosphate (cGMP)- and cyclic adenosine monophosphate (cAMP)-specific, respectively, has been described and PDE5- and PDE4-inhibitors induce cavernous smooth muscle relaxation. Whereas the NO/cGMP signaling pathway is well established in penile erection, the cAMP-mediated mechanism is not fully elucidated. The aim of this study is to investigate the localization and the functional significance of PDE4 in rat CC tone regulation., Main Methods: We performed immunohistochemistry for the detection of the PDE4A isoenzyme. Isometric tension recordings for roflumilast and tadalafil, PDE4 and PDE5 inhibitors, respectively, electrical field stimulation (EFS) and β-adrenoceptor agonist isoproterenol and endogenous H 2 S production measurement., Key Findings: A marked PDE4A expression was detected mainly localized in the nerve cells of the cavernous smooth muscle. Furthermore, roflumilast and tadalafil exhibited strong corpus cavernous relaxations. Endogenous H 2 S production was decreased by NO and H 2 S synthase inhibitors and increased by roflumilast. Isoproterenol- and EFS-induced relaxations were increased by roflumilast., Significance: These results indicate that PDE4A is mainly expressed within the nerves cells of the rat CC, where roflumilast induces a potent corpus cavernous relaxation per se and potentiates the response induced by β-adrenoceptor activation. The fact that roflumilast enhances H 2 S production, as well as EFS-elicited responses suggests that PDE4 inhibitors modulate, in a positive feedback fashion, nerve-mediated relaxation induced by gasotransmitters, thus indicating a key role for neuronal PDE4 in penile erection., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Background and Purpose: Metabolic syndrome causes adverse effects on the coronary circulation including altered vascular responsiveness and the progression of coronary artery disease (CAD). However the underlying mechanisms linking obesity with CAD are intricated. Augmented vasoconstriction, mainly due to impaired Ca 2+ homeostasis in coronary vascular smooth muscle (VSM), is a critical factor for CAD. Increased calcium-induced calcium release (CICR) mechanism has been associated to pathophysiological conditions presenting persistent vasoconstriction while increased store operated calcium (SOC) entry appears to activate proliferation and migration in coronary vascular smooth muscle (VSM). We analyze here whether metabolic syndrome might alter SOC entry as well as CICR mechanism in coronary arteries, contributing thus to a defective Ca 2+ handling and therefore accelerating the progression of CAD., Experimental Approach: Measurements of intracellular Ca 2+ ([Ca 2+ ] i ) and tension and of Ca 2+ channels protein expression were performed in coronary arteries (CA) from lean Zucker rats (LZR) and obese Zucker rats (OZR)., Key Results: SOC entry stimulated by emptying sarcoplasmic reticulum (SR) Ca 2+ store with cyclopiazonic acid (CPA) was decreased and associated to decreased STIM-1 and Orai1 protein expression in OZR CA. Further, CICR mechanism was blunted in these arteries but Ca 2+ entry through voltage-dependent L-type channels was preserved contributing to maintain depolarization-induced increases in [Ca 2+ ] i and vasoconstriction in OZR CA. These results were associated to increased expression of voltage-operated L-type Ca 2+ channel alpha 1C subunit (Ca V 1.2) but unaltered ryanodine receptor (RyR) and sarcoendoplasmic reticulum Ca 2+ -ATPase (SERCA) pump protein content in OZR CA., Conclusion and Implications: The present manuscript provides evidence of impaired Ca 2+ handling mechanisms in coronary arteries in metabolic syndrome where a decrease in both SOC entry and CICR mechanism but preserved vasoconstriction are reported in coronary arteries from obese Zucker rats. Remarkably, OZR CA VSM at this state of metabolic syndrome seemed to have developed a compensation mechanism for impaired CICR by overexpressing Ca V 1.2 channels., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The micro-elimination of HCV infection in drug users (DU) in our area is a priority in order to achieve the overall elimination of this disease. Coordinated action between specialists in addiction treatment, microbiologists and physicians who treat HCV infection is required to implement infection screening, to achieve universal access to treatment and to prevent new infections and reinfections. The objective of this document was to come to a consensus on the screening, hospital referral, treatment, follow-up and prevention of HCV infection in DU by an expert panel from GEHEP/SEIMC and three scientific societies of addiction treating physicians: SEPD, SOCIDROGALCOHOL and SOMAPA., (Copyright © 2018 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.)

Oxidative stress-associated endothelial dysfunction is a key pathogenic factor underlying the microvascular complications of metabolic disease. NADPH oxidase (Nox) is a major source of oxidative stress in diabetic nephropathy and chronic kidney disease, despite Nox4 and Nox2 have been identified as relevant sources of vasodilator endothelial H 2 O 2 .The present study was sought to investigate the role of Nox enzymes in renal vascular oxidative stress and endothelial dysfunction in a rat model of genetic obesity. Endothelial function was assessed in intrarenal arteries of obese Zucker rats (OZR) and their counterparts lean Zucker rats (LZR) mounted in microvascular myographs, and superoxide (O 2 .- ) and H 2 O 2 production were measured. Impaired endothelium-dependent relaxations to acetylcholine (ACh) were associated to augmented O 2 .- generation, but neither ROS scavengers nor the Nox inhibitor apocynin significantly improved these relaxant responses in renal arteries of OZR. Whereas NO contribution to endothelial relaxations was blunted, catalase-sensitive non-NO non-prostanoid relaxations were enhanced in obese rats. Interestingly, NADPH-dependent O 2 .- production was augmented while NADPH-dependent H 2 O 2 generation was reduced, and cytosolic and mitochondrial SOD were up-regulated in kidney of obese rats. Nox4 was down-regulated in renal arteries and Nox4-dependent H 2 O 2 generation and endothelial relaxation were reduced in OZR. Up-regulation of both Nox2 and Nox1 was associated with augmented O 2 .- production but reduced H 2 O 2 generation and blunted endothelial Nox2-derived H 2 O 2 -mediated in obese rats. Moreover, increased Nox1-derived O 2 .- contributed to renal endothelial dysfunction in OZR. In summary, the current data support a main role for Nox1-derived O 2 .- in kidney vascular oxidative stress and renal endothelial dysfunction in obesity, while reduced endothelial Nox4 expression associated to decreased H 2 O 2 generation and H 2 O 2 -mediated vasodilatation might hinder Nox4 protective renal effects thus contributing to kidney injury. This suggests that effective therapies to counteract oxidative stress and prevent microvascular complications must identify the specific Nox subunits involved in metabolic disease., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

The impact of obesity on vascular smooth muscle (VSM) Ca 2+ handling and vasoconstriction, and its regulation by the phosphatidylinositol 3-kinase (PI3K), mitogen activated protein kinase (MAPK) and protein kinase C (PKC) were assessed in mesenteric arteries (MA) from obese Zucker rats (OZR). Simultaneous measurements of intracellular Ca 2+ ([Ca 2+ ] i ) and tension were performed in MA from OZR and compared to lean Zucker rats (LZR), and the effects of selective inhibitors of PI3K, ERK-MAPK kinase and PKC were assessed on the functional responses of VSM voltage-dependent L-type Ca 2+ channels (Ca V 1.2). Increases in [Ca 2+ ] i induced by α 1 -adrenoceptor activation and high K + depolarization were not different in arteries from LZR and OZR although vasoconstriction was enhanced in OZR. Blockade of the ryanodine receptor (RyR) and of Ca 2+ release from the sarcoplasmic reticulum (SR) markedly reduced depolarization-induced Ca 2+ responses in arteries from lean but not obese rats, suggesting impaired Ca 2+ -induced Ca 2+ release (CICR) from SR in arteries from OZR. Enhanced Ca 2+ influx after treatment with ryanodine was abolished by nifedipine and coupled to up-regulation of Ca V 1.2 channels in arteries from OZR. Increased activation of ERK-MAPK and up-regulation of PI3Kδ, PKCβ and δ isoforms were associated to larger inhibitory effects of PI3K, MAPK and PKC blockers on VSM L-type channel Ca 2+ entry in OZR. Changes in arterial Ca 2+ handling in obesity involve SR Ca 2+ store dysfunction and enhanced VSM Ca 2+ entry through L-type channels, linked to a compensatory up-regulation of Ca V 1.2 proteins and increased activity of the ERK-MAPK, PI3Kδ and PKCβ and δ, signaling pathways., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background and Aims: The impact of obesity on vasomotor regulation of coronary arteries and its underlying mechanisms are not completely understood and, in particular, the role of BK Ca channels in the NO-mediated coronary vasodilation in obesity remains to be elucidated., Methods: The effects of selective blockade of BK Ca channel was tested on nitric oxide (NO)-mediated vasodilator responses of coronary arteries from lean and obese Zucker rats (LZR and OZR, respectively) by means of simultaneous measurements of intracellular Ca 2+ concentration ([Ca 2+ ] i ) by Fura-2 fluorescence and tension in endothelium-denuded coronary arteries mounted in microvascular myographs. BK Ca channel subunits expression was measured by Western blot., Results: The selective BK Ca channel blocker iberitoxin largely reduced the relaxations and decreases in [Ca 2+ ] i induced by a NO donor in coronary arteries from OZR. Iberitoxin increased to a great extent both basal [Ca 2+ ] i and tone in OZR. The agonist of the voltage-gated L-type calcium channels Bay K8644 induced an increase in [Ca 2+ ] i and tone that was significantly smaller in arteries from OZR, which was restored to control levels in LZR after BK Ca channel inhibition. Caffeine- and ryanodine-induced intracellular Ca 2+ mobilization and BK Ca channel β1 subunit expression were increased in arteries from OZR., Conclusions: The present study suggests that an enhanced activity of VSM BK Ca channels, associated with up-regulation of channel β1 subunit and with a higher intracellular Ca 2+ mobilization, contributes to the preserved NO-mediated vasodilatation and basal tone of coronary arteries in obesity., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background and Purpose: Oxidative stress plays a key role in the vascular and metabolic abnormalities associated with obesity. Herein, we assessed whether obesity can increase coronary vasoconstriction induced by hydrogen peroxide (H 2 O 2 ) and the signalling pathways involving COX-2 and superoxide (O 2 .- ) generation., Experimental Approach: Contractile responses to H 2 O 2 and O 2 .- generation were measured in coronary arteries from genetically obese Zucker rats (OZR) and compared to lean Zucker rats (LZR)., Key Results: Both basal and H 2 O 2 -stimulated O 2 .- production were enhanced in coronary arteries from OZR, but H 2 O 2 -induced vasoconstriction was unchanged. The selective COX-2 inhibitor NS398 significantly reduced H 2 O 2 -induced contractions in endothelium-denuded arteries from LZR and OZR, but only in endothelium-intact arteries from LZR. PGI 2 (IP) receptor antagonism modestly reduced the vasoconstrictor action of H 2 O 2 while antagonism of the PGE 2 receptor 4 (EP 4 ) enhanced H 2 O 2 contractions in arteries from OZR but not LZR. Basal release of COX-2-derived PGE 2 was higher in coronary arteries from OZR where the selective agonist of EP 4 receptors TCS 2519 evoked potent relaxations. COX-2 was up-regulated after acute exposure to H 2 O 2 in coronary endothelium and vascular smooth muscle (VSM) and inhibition of COX-2 markedly reduced H 2 O 2 -elicited O 2 .- generation in coronary arteries and myocardium. Expression of Nox subunits in VSM and NADPH-stimulated O 2 .- generation was enhanced and contributed to H 2 O 2 vasoconstriction in arteries from obese rats., Conclusion and Implications: COX-2 contributes to cardiac oxidative stress and to the endothelium-independent O 2 .- -mediated coronary vasoconstriction induced by H 2 O 2 in obesity, which is offset by the release of COX-2-derived endothelial PGE 2 acting on EP 4 vasodilator receptors., (© 2016 The British Pharmacological Society.)

Background and Purpose: Abnormal Ca(2+) metabolism has been involved in the pathogenesis of vascular dysfunction associated with oxidative stress. Here, we have investigated the actions of H2 O2 on store-operated Ca(2+) (SOC) entry in coronary arteries and assessed whether it is impaired in arteries from a rat model of metabolic syndrome., Experimental Approach: Simultaneous measurements of intracellular Ca(2+) concentration and contractile responses were made in coronary arteries from Wistar and obese Zucker rats, mounted in microvascular myographs, and the effects of H2 O2 were assessed., Key Results: H2 O2 raised intracellular Ca(2+) concentrations, accompanied by simultaneous vasoconstriction that was markedly reduced in a Ca(2+) -free medium. Upon Ca(2+) re-addition, a nifedipine-resistant sustained Ca(2+) entry, not coupled to contraction, was obtained in endothelium-denuded coronary arteries. The effect of H2 O2 on this voltage-independent Ca(2+) influx was concentration-dependent, and high micromolar H2 O2 concentrations were inhibitory and reduced SOC entry evoked by inhibition of the sarcoplasmic reticulum ATPase (SERCA). H2 O2 -induced increases in Fura signals were mimicked by Ba(2+) and reduced by heparin, Gd(3+) ions and by Pyr6, a selective inhibitor of the Orai1-mediated Ca(2+) entry,. In coronary arteries from obese Zucker rats, intracellular Ca(2+) mobilization and SOC entry activated by acute exposure to H2 O2 were augmented and associated with local oxidative stress., Conclusion and Implications: H2 O2 exerted dual concentration-dependent stimulatory/inhibitory effects on store-operated, IP3 receptor-mediated and Orai1-mediated Ca(2+) entry, not coupled to vasoconstriction in coronary vascular smooth muscle. SOC entry activated by H2 O2 was enhanced and associated with vascular oxidative stress in coronary arteries in metabolic syndrome., (© 2015 The British Pharmacological Society.)

Background and Aims: Endothelial small- and intermediate-conductance KCa channels, SK3 and IK1, are key mediators in the endothelium-derived hyperpolarization and relaxation of vascular smooth muscle and also in the modulation of endothelial Ca2+ signaling and nitric oxide (NO) release. Obesity is associated with endothelial dysfunction and impaired relaxation, although how obesity influences endothelial SK3/IK1 function is unclear. Therefore we assessed whether the role of these channels in the coronary circulation is altered in obese animals., Methods and Results: In coronary arteries mounted in microvascular myographs, selective blockade of SK3/IK1 channels unmasked an increased contribution of these channels to the ACh- and to the exogenous NO- induced relaxations in arteries of Obese Zucker Rats (OZR) compared to Lean Zucker Rats (LZR). Relaxant responses induced by the SK3/IK1 channel activator NS309 were enhanced in OZR and NO- endothelium-dependent in LZR, whereas an additional endothelium-independent relaxant component was found in OZR. Fura2-AM fluorescence revealed a larger ACh-induced intracellular Ca2+ mobilization in the endothelium of coronary arteries from OZR, which was inhibited by blockade of SK3/IK1 channels in both LZR and OZR. Western blot analysis showed an increased expression of SK3/IK1 channels in coronary arteries of OZR and immunohistochemistry suggested that it takes place predominantly in the endothelial layer., Conclusions: Obesity may induce activation of adaptive vascular mechanisms to preserve the dilator function in coronary arteries. Increased function and expression of SK3/IK1 channels by influencing endothelial Ca2+ dynamics might contribute to the unaltered endothelium-dependent coronary relaxation in the early stages of obesity.

This review is focused on the effects of obesity on function and expression of potassium (K) channels in the vasculature. Five families of K channels have been identified in the vascular wall, calcium-activated K (KCa) channels, inward-rectifier K (KIR) channels, ATP-sensitive K (KATP) channels, voltage-gated K (KV) channels and two-pore domain K (K2P) channels. In endothelial cells (EC) and vascular smooth muscle cells (VSMC) opening of K channels leads to hyperpolarisation followed by vasodilatation. In some vascular beds of animal models of obesity, vasodilatation mediated by KCa3.1 and KCa2.3 channels has been reported to remain unaltered or even increased, whereas vasodilatation involving KCa1.1 channel has consistently been reported to be impaired. Changes in expression and function of KIR and KATP channels have also been associated with impaired vasodilatation in animal models of obesity, and therefore activation of these channels may improve endothelial function and reduce the risk of major cardiovascular events. Expression of KV7.x channels is downregulated in small arteries from hypertensive animals and it would be interesting to assess whether these channels contribute to development of hypertension in obese patients. However, the role of KV7.x and K2P channels in regulation of blood pressure remains unexplored compared to other K channels. In conclusion, obesity and metabolic syndrome alter expression, function and sensitivity of vascular K channel subtypes causing smooth muscle dysfunction and probably endothelial dysfunction which makes these patients particularly prone to premature cardiovascular disease. Modulation of K channel activity by use of openers of e.g. KCa and KATP channels may also be attractive to counteract vascular dysfunction observed in obesity.

Introduction: Erectile dysfunction is considered as an early sign of subclinical vascular disease and endothelial dysfunction and a highly prevalent condition in diabetic patients., Aim: The current study assessed whether impaired vascular effects of endothelin (ET)-1 may contribute to the vascular dysfunction of penile arteries from a rat model of insulin resistance., Methods: The effect of ETA and ETB receptor antagonists was assessed on the intracellular Ca(2+) [Ca(2+) ]i and contractile responses to ET-1 in penile arteries from obese Zucker rats (OZR) and lean Zucker rats (LZR), and ET receptor expression in the arterial wall was assessed by immunohistochemistry., Main Outcome Measure: Changes in ET-1 [Ca(2+) ]i and vasoconstriction and ET receptor expression were evaluated in penile arteries from insulin-resistant rats., Results: ET-1-induced vasoconstriction was associated with a higher increase in smooth muscle [Ca(2+) ]i in penile arteries from OZR compared with LZR. Removal of the endothelium inhibited and enhanced contractions to the lowest and highest doses of ET-1, respectively, mainly in OZR. The selective ETA receptor antagonist BQ-123 inhibited ET-1 vasoconstriction and [Ca(2+) ]i response in both LZR and OZR. The ETB receptor antagonist BQ-788 had little effect in healthy arteries but markedly inhibited ET-1-induced increases in [Ca(2+) ]i and vasoconstriction in arteries from OZR. ETA receptors were located on the smooth muscle and endothelium of penile arteries, whereas ETB receptors were found on the arterial endothelium in LZR and OZR, and also on the smooth muscle in OZR, immunostaining for both receptors being higher in OZR., Conclusion: Penile arteries from OZR exhibit an impaired ET-1 Ca(2+) signaling along with changes in the ET receptor profile. Thus, whereas ET-1 contraction and the associated [Ca(2+) ]i increase are mediated by smooth muscle ETA receptors in healthy arteries, ETB receptors contribute to contraction and are coupled to the augmented ET-1 [Ca(2+) ]i response under conditions of insulin resistance., (© 2013 International Society for Sexual Medicine.)

Hydrogen peroxide (H2O2) is an endogenous endothelium-derived hyperpolarizing factor released by flow and involved in the regulation of coronary blood flow. Because opposing vasoactive effects have been reported for H2O2 depending on the vascular bed and experimental conditions, the aim of this study was to assess whether H2O2 may act as a coronary vasoconstrictor and if so to determine the underlying signaling mechanisms. Intramyocardial arteries from male Wistar rats were mounted on microvascular myographs for simultaneous measurements of intracellular Ca(2+) ([Ca(2+)]i) and tension. On coronary arteries precontracted with the thromboxane A2 (TxA2) analogue U46619, H2O2 (1-300μM) elicited further moderate contractions in the proximal arterial segments and relaxed the more distal coronary branches, the contractions being markedly augmented in arteries depolarized by raising extracellular K(+). H2O2-elicited vasoconstriction on K(+)30-precontracted coronary arteries was blunted by catalase and significantly reduced by endothelial cell removal and by inhibitors of cyclooxygenase (COX) and of the TxA2 receptor (TP). H2O2 (50μM) increased by about 10-fold basal superoxide anion (O2(-)) production in coronary arteries measured by lucigenin-enhanced chemiluminescence, and H2O2-elicited contractions were reduced by the superoxide dismutase mimetic tempol and by NADPH oxidase inhibition. Furthermore, blockade of the ERK and p38 mitogen-activated protein (MAP) kinases significantly reduced the contractions elicited by high and low concentrations of peroxide, respectively, whereas Rho kinase inhibition nearly abolished these responses. H2O2 (50μM) elicited simultaneous and similar sustained increases in [Ca(2+)]i and tension that were blunted by blockade of voltage-dependent L-type channels, but resistant to the nonselective Ca(2+) channel blocker 2-aminoethoxydiphenyl borate. Moreover, endothelial cell removal reduced the increases in [Ca(2+)]i and contraction elicited by peroxide. The present data demonstrate that H2O2 is an endothelium-dependent vasoconstrictor in rat coronary arteries that activates smooth muscle Ca(2+) entry through L-type and non-L-type channels and various intracellular signaling pathways including the release of a COX-derived TP agonist, stimulation of the MAP and Rho kinase pathways, and production of NADPH oxidase-derived superoxide., (Copyright © 2013 Elsevier Inc. All rights reserved.)

The use of medicines, with or without medical prescription, for recreational ends by the young population has received little attention from doctors. In the USA, one in five adolescents has used medicines for recreational purposes, and consultations in Emergency Departments for medicine abuse have exceeded those for illegal drugs. Although few data are available in Spain, such consumption is situated between 3.1 and 8.6% according to surveys. The medicines most used are dextromethorphan and methylphenidate. The former, on sale without prescription, presents a varied symptomatology, dosage and dependent metabolic action, ranging from euphoria to hallucinations. Methylphenidate, taken orally, nasally or intravenously, is used as a stimulant in substitution for cocaine and is one of the medicines most diverted onto the illicit market at the world level. In principle, other substances like modafinil and propofol present a limited incidence of non-medical use, but they have a probable abuse potential that should be borne in mind, above all in the health context. Finally, opiates like fentanyl, oxycodone and buprenorphine, with new pharmaceutical presentations, have recently become generalized in the therapeutic arsenal of many medical specialities; they are giving rise to phenomena of abuse, dependence and diversion towards the illicit market. Demands for detoxification treatment, their mixture with illegal substances, and cases of death should alert us to the abuse of these medicines.

Endothelial cells (EC) control vascular smooth muscle cell (VSMC) tone by release of paracrine factors. VSMC may also influence the EC layer, and therefore, the present study hypothesized that the opening of large-conductance Ca(2+) activated K(+) (BK(Ca)) channels may indirectly modulate EC hyperpolarization and nitric oxide (NO) release via myoendothelial gap junctions (MEGJ). To address this hypothesis 'in situ' EC ion current recordings, isolated VSMC patch clamp recordings, and simultaneous measurements of NO concentration and relaxation were conducted using segments of the rat superior mesenteric artery. In arteries constricted by α(1)-adrenoceptor activation, ACh (1 μM) evoked EC outward currents, vasorelaxation, and NO release. In contrast to preincubation with iberiotoxin (IbTx, 100nM) application of IbTx after ACh decreased EC outward currents, NO release and vasorelaxation. Furthermore, in phenylephrine (Phe)-contracted arteries treated with a gap junction uncoupler, cabenoxolone (CBX), IbTx failed to decrease ACh-evoked EC outward currents. In addition, CBX decreased EC outward currents, time constant of the capacitative transients, input capacitance, and increased input resistance. In isolated VSMC CBX did not affect BK(Ca) currents. Immunohistochemistry revealed only BK(Ca) channel positive staining in the VSMC layer. Therefore, the present results suggest that BK(Ca) channels are expressed in the VSMC, and that Phe by activation of VSMC BK(Ca) channels modulates ACh-evoked EC outward currents, NO release and vasorelaxation via MEGJ in rat superior mesenteric artery., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Objective: Erectile dysfunction (ED) is considered as an early sign of vascular disease due to its high prevalence in patients with cardiovascular risk factors. Endothelial and neural dysfunction involving nitric oxide (NO) are usually implicated in the pathophysiology of the diabetic ED, but the underlying mechanisms are unclear. The present study assessed the role of oxidative stress in the dysfunctional neural vasodilator responses of penile arteries in the obese Zucker rat (OZR), an experimental model of metabolic syndrome/prediabetes., Methods and Results: Electrical field stimulation (EFS) under non-adrenergic non-cholinergic (NANC) conditions evoked relaxations that were significantly reduced in penile arteries of OZR compared with those of lean Zucker rats (LZR). Blockade of NO synthase (NOS) inhibited neural relaxations in both LZR and OZR, while saturating concentrations of the NOS substrate L-arginine reversed the inhibition and restored relaxations in OZR to levels in arteries from LZR. nNOS expression was unchanged in arteries from OZR compared to LZR and nNOS selective inhibition decreased the EFS relaxations in LZR but not in OZR, while endothelium removal did not alter these responses in either strain. Superoxide anion production and nitro-tyrosine immunostaining were elevated in the erectile tissue from OZR. Treatment with the NADPH oxidase inhibitor apocynin or acute incubation with the NOS cofactor tetrahydrobiopterin (BH4) restored neural relaxations in OZR to levels in control arteries, while inhibition of the enzyme of BH4 synthesis GTP-cyclohydrolase (GCH) reduced neural relaxations in arteries from LZR but not OZR. The NO donor SNAP induced decreases in intracellular calcium that were impaired in arteries from OZR compared to controls., Conclusions: The present study demonstrates nitrergic dysfunction and impaired neural NO signalling due to oxidative stress and nNOS uncoupling in penile arteries under conditions of insulin resistance. This dysfunction likely contributes to the metabolic syndrome-associated ED, along with the endothelial dysfunction also involving altered NO signalling.

Benign prostatic hypertrophy has been related with glandular ischemia processes and adenosine is a potent vasodilator agent. This study investigates the mechanisms underlying the adenosine-induced vasorelaxation in pig prostatic small arteries. Adenosine receptors expression was determined by Western blot and immunohistochemistry, and rings were mounted in myographs for isometric force recording. A(2A) and A(3) receptor expression was observed in the arterial wall and A(2A)-immunoreactivity was identified in the adventitia-media junction and endothelium. A(1) and A(2B) receptor expression was not obtained. On noradrenaline-precontracted rings, P1 receptor agonists produced concentration-dependent relaxations with the following order of potency: 5'-N-ethylcarboxamidoadenosine (NECA) = CGS21680 > 2-Cl-IB-MECA = 2-Cl-cyclopentyladenosine = adenosine. Adenosine reuptake inhibition potentiated both NECA and adenosine relaxations. Endothelium removal and ZM241385, an A(2A) antagonist, reduced NECA relaxations that were not modified by A(1), A(2B), and A(3) receptor antagonists. Neuronal voltage-gated Ca(2+) channels and nitric oxide (NO) synthase blockade, and adenylyl cyclase activation enhanced these responses, which were reduced by protein kinase A inhibition and by blockade of the intermediate (IK(Ca))- and small (SK(Ca))-conductance Ca(2+)-activated K(+) channels. Inhibition of cyclooxygenase (COX), large-conductance Ca(2+)-activated-, ATP-dependent-, and voltage-gated-K(+) channel failed to modify these responses. These results suggest that adenosine induces endothelium-dependent relaxations in the pig prostatic arteries via A(2A) purinoceptors. The adenosine vasorelaxation, which is prejunctionally modulated, is produced via NO- and COX-independent mechanisms that involve activation of IK(Ca) and SK(Ca) channels and stimulation of adenylyl cyclase. Endothelium-derived NO playing a regulatory role under conditions in which EDHF is non-functional is also suggested. Adenosine-induced vasodilatation could be useful to prevent prostatic ischemia.

Background and Purpose: Vascular endothelial and smooth muscle cell phenotypes may change dramatically after isolation and in cell cultures. This study was designed to investigate gap junctions coupling in an integrated intact preparation and to test if K(IR) channels modulate resting membrane conductance in "in situ" endothelial cells (EC), and acetylcholine (ACh)-evoked relaxation of the rat superior mesenteric artery., Experimental Approach: Whole cell blind patch recordings of ionic currents from in situ EC, dye-coupling experiments, and functional studies were performed in rat superior mesenteric artery., Key Results: EC were dye-coupled through gap junctions. 18β-glycyrretinic acid (25 μM) decreased outward and inward currents, the 80% decay of time and time constant of the capacitative transients, capacitance, and increased input resistance. Barium chloride (30 μM) decreased resting and ACh-evoked inward currents, the sensitivity of ACh-evoked relaxation, and decreased both the sensitivity and the maximal relaxation to S-nitroso-N-acetyl penicillamine in arteries with, but not in arteries without endothelium., Conclusions: The present results suggest that the EC layer of this large artery is electrically coupled, and that K(IR) channels regulate resting inward conductance, hence suggesting that they are of importance for resting membrane potential in in situ EC. Moreover, EC K(IR) channels are involved in ACh-evoked relaxation., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background and Purpose: Metabolic and cardiovascular abnormalities accompanying metabolic syndrome, such as obesity, insulin resistance and hypertension, are all associated with endothelial dysfunction and are independent risk factors for erectile dysfunction. The purpose of the present study was to investigate the vascular effects of insulin in penile arteries and whether these effects are impaired in a rat model of insulin resistance and metabolic syndrome., Experimental Approach: Penile arteries from obese Zucker rats (OZR) and their counterpart, lean Zucker rats (LZR), were mounted on microvascular myographs and the effects of insulin were assessed in the absence and presence of endothelium and of specific inhibitors of nitric oxide (NO) synthesis, phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK). Insulin-induced changes in intracellular Ca(2+) concentration [Ca(2+)](i) were also examined. KEY RESULTS OZR exhibited mild hyperglycaemia, hypercholesterolemia, hypertryglyceridemia and hyperinsulinemia. Insulin induced endothelium- and NO-dependent relaxations in LZR that were impaired in OZR. Inhibition of PI3K reduced relaxation induced by insulin and by the beta-adrenoceptor agonist isoprenaline, mainly in arteries from LZR. Antagonism of endothelin 1 (ET-1) receptors did not alter insulin-induced relaxation in either LZR or OZR, but MAPK blockade increased the responses in OZR. Insulin decreased [Ca(2+)](i), a response impaired in OZR., Conclusions and Implications: Insulin-induced relaxation was impaired in penile arteries of OZR due to altered NO release through the PI3K pathway and unmasking of a MAPK-mediated vasoconstriction. This vascular insulin resistance is likely to contribute to the endothelial dysfunction and erectile dysfunction associated with insulin resistant states.

Since endothelin-1 (ET-1) is involved in prostatic disorders, the current study investigated the mechanisms underlying the ET-1-induced effects in pig prostatic small arteries. The experiments were performed in rings mounted in microvascular myographs containing physiological saline solution at 37oC for isometric force recordings. On basal tension, ET-1 (0.1-30 nM) evoked concentration-dependent contractions, which were enhanced by endothelium removal. ET-1 contractions were inhibited by blockade of endothelin ETA and ETB receptors, extracellular Ca2+ removal and blockade of voltage-dependent (L-type)- and non-voltage-dependent-Ca2+ channels. On endothelium intact rings precontracted with noradrenaline, the ETB endothelin receptor agonist BQ3020 promoted a concentration-dependent relaxation which was reduced by blockade of ETB receptors, nitric oxide synthase, guanylyl cyclase and prostanoids synthesis. Endothelium removal abolished its relaxant response and unmasked a BQ3020-induced contraction. Tetraethylammonium and 4-aminopyridine, blockers of non-selective K+ channels and voltage-dependent K+ (Kv) channels, respectively, inhibited the relaxations to BQ3020. Iberiotoxin, apamin and glibenclamide, blockers of large and small Ca2+-activated- and ATP-dependent- K+ channels, respectively, failed to modify these responses. These data suggest that ET-1 promotes contraction of pig prostatic small arteries by activating vascular smooth muscle contractile endothelin ETA and ETB receptors coupled to extracellular Ca2+ entry, via voltage-dependent (L-type)- and non-voltage-dependent Ca2+ channels, also being due to intracellular Ca2+ mobilization. In addition, a population of endothelial ETB receptors mediates vasorelaxation via NO-cGMP pathway, vasodilator cyclooxygenase product(s) and Kv channels., (Copyright (c) 2010 Elsevier B.V. All rights reserved.)

Introduction: Lithium salts have been mainly used in the treatment of bipolar disorder. Because of its narrow therapeutic range, and several well characterised adverse effects, serum lithium levels must be monitored regularly in patients given lithium treatment in order to prevent intoxication., Objective: To describe the clinic and toxic characteristics in inpatients at our Clinic Toxicologic Unit., Material and Methods: Descriptive and retrospective study of lithium intoxications in 150 inpatients between 2003 and 2006. Patients were classified based on their neuropsychiathric symptom profile and serum lithium levels., Results: Sixteen of 150 inpatients had lithium intoxication: 58.3% women and 43.8% men; 49.19% +/- 18.49% years old. Lithium was used as treatment of bipolar disorder in 87.5% of cases. The most frequent cause of intoxication was attempted suicide. Using neuropsychiatric parametres, intoxication was moderate in 50% of cases, and mild in 25% and severe or very severe in 25%. Using serum lithium levels, intoxication was very severe in 31.35%, severe in 25%, and slight-moderate in 43.7%. Conservative measures were used as the most frequent treatment (50%), and haemodialfiltration was needed in 37.5%. Mean stay was 4,8 days in acute intoxication, and 11.2 days in chronic. Sequelaes were found in two patients (ataxia). Death was not present., Conclusions: Lithium intoxications can involve severe complications, even death. Narrow control is encouraged in polymedicated and elderly patients, and in concommitant treatment with antidepressant and neuroleptics.

To analyze the cerebrovascular effects of ischemia-reperfusion, cerebrovascular reactivity to ADP was studied after inducing 60-min occlusion followed by 60-min reperfusion of the left middle cerebral artery (MCA) in anesthetized goats. In 12 goats, at the end of reperfusion, left MCA resistance was decreased by 19%, and reactive hyperemia to 5- and 10-s occlusions as well as the cerebral vasodilatation to ADP (0.03-0.3 microg) but not to sodium nitroprusside (0.3-3 microg) was decreased. In 28 animals, killed at the end of reperfusion, segments 3-mm long were obtained from the left (ischemic) and right (control) MCA, prepared for isometric tension recording, and precontracted with the thromboxane A2 analogue U46619. The relaxation to ADP (10(-8) to 10(-5) M) but not to sodium nitroprusside (10(-8) to 10(-4) M) was lower in ischemic arteries. L-NAME (inhibitor of nitric oxide synthesis, 10(-4) M), charybdotoxin (10(-7) M)+apamin (10(-6) M) (blockers of KCa), or catalase (1000 U/ml) reduced the relaxation to ADP only in control arteries. Charybdotoxin+apamin further augmented the L-NAME-induced reduction in the relaxation to ADP in control arteries. The inhibitor of cyclooxygenase meclofenamate (10(-5) M) increased the relaxation to ADP only in ischemic arteries. The superoxide dismutase mimetic tiron (10(-2) M) increased the ADP-induced relaxation only in ischemic arteries. Therefore, it is suggested that ischemia-reperfusion produces cerebrovascular endothelial dysfunction, which may be associated with decreased nitric oxide bioavailability, decreased release of an EDHF, and increased production of vasoconstrictor prostanoids. All these alterations may be related in part with an increased production of superoxide anion.