Exogenous Noradrenaline Research Articles

Role of ERK and NF-KB pathway in neurally mediated enhanced expression and traffcking of SGLT2 in congestive heart failure

Congestive heart failure (CHF) is characterized by the activation of neurohumoral systems concomitant with avid fluid retention. Recently we showed enhanced expression of sodium-glucose cotransporter 2 (SGLT2) in rats with CHF. However, the exact molecular mechanism linking enhanced sympathetic tone and enhanced expression and translocation of SGLT2 in CHF is not clear. The objective of this study was to investigate the role of enhanced sympathetic tone on the expression and traffcking of SGLT2 via activation of protein kinase A (PKA), extracellular signal-regulated kinases (ERK), and nuclear factor kappa B (NF-KB) in the renal cortex of CHF rats. Male Sprague Dawley rats were subjected to either the left coronary artery ligation for the CHF group or Sham surgery. Four weeks after surgery, expression of protein levels (PKA, ERK and NF-KB) were assessed by Western blotting, whereas the location of SGLT2 expression was determined by immunohistological and immunofluorescent staining in the cortical region of kidneys from Sham and CHF rats. Effect of exogenous norepinephrine (NE) (10μM for 24hrs) on expression and traffcking of SGLT2, phosphorylation of ERK and NF-KB in HK2 cells were examined in an in vitro model. Expression of SGLT2 was significantly enhanced in the renal cortex of rats with CHF versus Sham (0.83±0.06 vs. 0.58±0.02). Also, the translocation of SGLT2 was significantly enhanced towards the membrane in CHF rats (0.92±0.11 vs. 0.33±0.07). Phosphorylation of PKA (0.05±0.01 vs. 0.01±0.01), ERK (0.32±0.02 vs. 0.23±0.02) and NF-KB (0.71±0.14 vs. 0.08±0.06) were significantly enhanced in CHF compared to Sham. NE treatment significantly increased expression of SGLT2 (0.26±0.03 vs. 0.15±0.02), traffcking of SGLT2 (0.45 ± 0.09 vs. 0.15 ± 0.03) towards membrane, phosphorylation of ERK (0.38±0.05 vs. 0.14±0.02) and NF-KB (0.61±0.08 vs. 0.17±0.07) in HK2 cells. Thus, NE treatment enhanced the phosphorylation of ERK, NF-kB as well as traffcking of SGLT2. Immunohistological and immunofluorescent staining demonstrated increased expression of SGLT2 in the kidneys of rats with CHF. Similar results were observed in immunofluorescent staining of human kidney cells treated with NE. In conclusion, these findings indicate that NE activates ERK and NF-KB pathways which leads to enhanced traffcking and overexpression of SGLT2 in CHF. These results provide a molecular link between enhanced sympathetic tone, ERK and NF-KB pathway and the traffcking of SGLT2 to the luminal membrane of renal proximal tubular cells and consequent increase in sodium retention in rats with CHF. This study was funded by NIH R01-DK-129311. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Tonic noradrenergic input to neurons in the dorsal raphe nucleus mediates food intake in male mice

The dorsal raphe nucleus (DRN) is essential for the control of food intake. Efferent projections from the DRN extend to several forebrain regions that are involved in the control of food intake. However, the neurotransmitters released in the DRN related to the control of food intake are not known. We have previously demonstrated that a tonic α1 action on DRN neurons contributes to satiety in the fed rats. In this study we investigated the participation of norepinephrine (NE) signaling in the DRN in the satiety response. Intra-DRN administration of NE causes an increase in the 2-hour food intake of sated mice, an effect that was blocked by previous administration of yohimbine, an α2 antagonist. Similarly, Intra-DRN administration of clonidine, an α2 agonist, increases food intake in sated mice. This result indicates that in the satiated mice exogenous NE acts on α2 receptors to increase food intake. Furthermore, administration of phenylephrine, an α1 agonist, decreases food intake in fasted mice and prazosin, an α1 antagonist, increases food intake in the sated mice. Taken together these results indicate that, in a satiated condition, a tonic α1 adrenergic action on the DRN neurons inhibits food intake and that exogenous NE administered to the DRN acts on α2 adrenergic receptors to increase food intake. These data reinforce the intricate neuronal functioning of the DRN and its effects on feeding.

Improvement of Vascular Insulin Sensitivity by Ranolazine.

Ranolazine (RN) is a drug used in the treatment of chronic coronary ischemia. Different clinical trials have shown that RN behaves as an anti-diabetic drug by lowering blood glucose and glycosylated hemoglobin (HbA1c) levels. However, RN has not been shown to improve insulin (IN) sensitivity. Our study investigates the possible facilitating effects of RN on the actions of IN in the rabbit aorta. IN induced vasodilation of the abdominal aorta in a concentration-dependent manner, and this dilatory effect was due to the phosphorylation of endothelial nitric oxide synthase (eNOS) and the formation of nitric oxide (NO). On the other hand, IN facilitated the vasodilator effects of acetylcholine but not the vasodilation induced by sodium nitroprusside. RN facilitated all the vasodilatory effects of IN. In addition, IN decreased the vasoconstrictor effects of adrenergic nerve stimulation and exogenous noradrenaline. Both effects were in turn facilitated by RN. The joint effect of RN with IN induced a significant increase in the ratio of p-eNOS/eNOS and pAKT/AKT. In conclusion, RN facilitated the vasodilator effects of IN, both direct and induced, on the adrenergic system. Therefore, RN increases vascular sensitivity to IN, thus decreasing tissue resistance to the hormone, a key mechanism in the development of type II diabetes.

Noradrenergic α1, α2, and β1receptors mediate VNS-induced theta oscillations

Although vagal nerve stimulation (VNS) has been employed with success for almost four decades in many central nervous system disturbances, the physiological and pharmacological processes underlying this therapy are still unclear. Searching for central mechanisms of VNS is clinically limited. Hence, in many experiments, VNS technique is tested on the model of laboratory animals. In the present study we proceed with the experiments to verify some central effects of VNS. Specifically, we focussed on the hippocampal formation (HPC) noradrenergic profile which underlines the VNS-induced theta oscillations in anesthetized rats (Broncel et al., 2017; 2021). The effects of noradrenaline (NE) and selective noradrenergic α and β agonists and antagonists were tested in experiments organized in three stages. Initially, a nonspecific noradrenergic agonist, noradrenaline, was administrated. In the second stage, noradrenergic α and β agonists were applied. In the last stage, the administration of selected agonists was pretreated by specific antagonists. The results of the present study provide evidence that the selective activation of HPC α1, α2, and β1 noradrenergic receptors produce the inhibition of VNS-induced theta oscillations. Hippocampal β2 and β3 receptors were found not to be involved in the modulation of oscillations produced by the vagal nerve stimulation. The obtained outcomes are discussed in light of the effects of increased exogenous NE and induced release of endogenous NE.

Real-time monitoring norepinephrine exocytosis by high K+via an endoplasmic reticulum-targeting fluorescent probe.

Norepinephrine (NE), a neurotransmitter, has multiple functions in the neural system and peripheral organs. Abnormal levels of NE may lead to numerous neuro-degenerative and psychiatric disorders, such as Parkinson's disease, depression and Alzheimer's disease. Moreover, studies have indicated that an increase in NE may induce endoplasmic reticulum (ER) stress and cell apoptosis via oxidative stress. Therefore, developing a measure to monitor NE levels in the ER appears to be particularly important. The fluorescence imaging technique has become an ideal tool for detecting various biological molecules in situ, with the advantages of high selectivity, nondestructive testing, and real-time dynamic monitoring. However, there are currently no activatable ER fluorescent probes that can be used to monitor NE levels in the ER. Herein, a robust ER-targetable fluorescence probe (ER-NE) for detecting NE in the ER was constructed for the first time. With the excellent properties of high selectivity, low cytotoxicity and good biocompatibility for NE detection, ER-NE successfully achieved the detection of endogenous and exogenous NE under physiological conditions. More importantly, a probe was further applied to monitor NE exocytosis stimulated by continuous incubation with high K+. We expect that the probe may serve as a powerful tool for detecting NE and provide a potential new diagnostic method for related neurodegenerative diseases.

Ligamentum arteriosum: Muscular and contractile.

Ductus arteriosus is a muscular artery in fetal circulation, spanning from the bifurcation of the pulmonary trunk to the aortic arch, shunting blood directly from pulmonary circulation into systemic circulation thus by-passing the fluid-filled lungs. Postnatally, it changes name to the ligamentum arteriosum (LA), when a cascade of anatomical and physiological processes leads to its closure. Though the LA has generally been considered as a fibrosed remnant of the ductus arteriosus, anecdotal and contradictory reports still describe the LA as a small muscular artery. We hypothesized the likelihood of contractile muscular elements retainment in this so-called ligament. To investigate this, mediastinum of wild-type mouse, pig, and human LA were subjected to routine and special histological staining, single-immunolabeling, electron microscopy (mouse and pig only), and tension recording of explanted pig LA in organ bath experiments. Contrary to a canonical ligament, the LA was mainly made up of α-smooth muscle actin-positive cells in all three species, confirmed by routine and special histological staining as well as transmission electron microscopy. Myocytes within the LA contracted in response to exogenous noradrenalin (NA). NA-induced precontracted LA relaxed upon administration of the α1-adrenergic blockers (prazosin and tamsulosin). Though the LA does not function in its original capacity as fetal shunt, it is clearly not a passive structure, and may be described as muscular and contractile. The contractile abilities of LA myocytes may act on the two great vessels to which it is attached causing a change in their distensibility.

Effect of sarpogrelate treatment on 5-HT modulation of vascular sympathetic innervation and platelet activity in diabetic rats

This study aimed to investigate whether the 5-HT2 receptor blockade alters the 5-HT effect on vascular sympathetic neurotransmission and platelet activation in type 1 diabetes. 28-day diabetes was obtained by alloxan (150 mg/kg; s.c.) in male Wistar rats, administering sarpogrelate (5-HT2 blocker; 30 mg/kg/day; p.o.) for 14 days. Blood glucose and body weight were monitored for 28 days. After 4 weeks of diabetes induction, food and drink intake, urine, plasma-platelet 5-HT, and platelet activation were determined in normoglycemic, non-treated diabetic and sarpogrelate-treated diabetic rats. Another set of diabetic rats were pithed to run the vascular sympathetic stimulation or exogenous noradrenaline administration, examining the induced vasoconstrictor responses. Sarpogrelate treatment significantly reduced drink intake and urine, whereas BW gain, hyperglycemia, and food intake were not modified in diabetic rats. The platelet activation and plasma 5-HT concentration were decreased (increasing the stored 5-HT platelet) by 5-HT2 blockade in diabetic animals. The sympathetic-induced vasoconstrictions were higher in non-treated than in sarpogrelate-treated diabetic rats. 5-HT inhibited these vasopressor responses, reproduced exclusively by the 5-HT1/5/7 receptor agonist, 5-CT. The 5-CT-produced inhibition was partly reversed by 5-HT1D or 5-HT7 antagonists (LY310762 or SB-258719, respectively), and totally annulled by the mixture of LY310762+SB‐258719. Noradrenaline-caused vasoconstrictions were also decreased by 5-CT. In conclusion, our results reveal that 14-day sarpogrelate treatment improves polydipsia and polyuria, reduces platelet hyperactivation, plasma 5-HT and the vascular sympathetic tone, and changes 5-HT receptors inhibiting noradrenergic drive in diabetic rats: pre and/or postjunctional 5-HT1D/7 are involved in the sympatho-inhibition.

Is Infantile Hemangioma a Neuroendocrine Tumor?

Infantile hemangioma (IH) is the most common infantile tumor, affecting 5–10% of newborns. Propranolol, a nonselective β-adrenergic receptor (ADRB) antagonist, is currently the first-line treatment for severe IH; however, both its mechanism of action and its main cellular target remain poorly understood. Since betablockers can antagonize the effect of natural ADRB agonists, we postulated that the catecholamine produced in situ in IH may have a role in the propranolol response. By quantifying catecholamines in the IH tissues, we found a higher amount of noradrenaline (NA) in untreated proliferative IHs than in involuted IHs or propranolol-treated IHs. We further found that the first three enzymes of the catecholamine biosynthesis pathway are expressed by IH cells and that their levels are reduced in propranolol-treated tumors. To study the role of NA in the pathophysiology of IH and its response to propranolol, we performed an in vitro angiogenesis assay in which IH-derived endothelial cells, pericytes and/or telocytes were incorporated. The results showed that the total tube formation is sensitive to propranolol only when exogenous NA is added in the three-cell model. We conclude that the IH’s sensitivity to propranolol depends on crosstalk between the endothelial cells, pericytes and telocytes in the context of a high local amount of local NA.

Ligamentum Arteriosum: An Innervated and Contractile Muscular Structure

IntroductionThe ligamentum arteriosum (LA) is generally described as a mere fibrotic remnant of the embryonic bypass (ductus arteriosus) from the pulmonary trunk to the aortic arch, obliterating soon after childbirth. There have been anecdotal and contradictory reports on this speculated morphological change. This study set out to elucidate the morphology, innervation, neurochemistry and function of LA.MethodLA of human, pig, wild‐type and appropriate transgenic reporter mouse strains were studied using routine and special histological staining methods, single‐ and double‐immunofluorescence labeling using antibodies directed against structural markers such as α‐smooth muscle actin (αSMA) and protein gene product 9.5 (PGP 9.5), against neuropeptides such as neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), substance P (SP), and calcitonin gene‐related peptide (CGRP), and against transmitter synthesizing enzymes such as tyrosine hydroxylase (TH; noradrenergic), choline acetyltransferase (ChAT; cholinergic), and nitric oxide synthase (NOS). Additionally, pig and mice LA were investigated using transmission electron microscopy (TEM). Organ bath experiments subjected pig LA to increasing cumulative doses of exogenous noradrenalin (NA), ɑ1‐adrenergic antagonists (tamsulosin and prazosin) and varying Hz of electrical field stimulation.ResultsContrary to a canonical ligament, the LA was mainly made up by αSMA‐positive cells in all three species. TEM confirmed the presence of smooth muscle cells with caveolae, mmyofilaments’, dense bands etc. within the LA. The ligament received a noticeable amount of noradrenergic (TH, NPY) and sensory (CGRP, SP) but no cholinergic innervation in all three species investigated. The LA exhibited a dose‐ and frequency‐dependent contraction in response to cumulative doses of exogenous NA and electrical field stimulation respectively. Furthermore, NA pre‐contracted LA relaxed to baseline upon administration of ɑ1‐adrenergic antagoniststs (tamsulosin and prazosin).ConclusionThe LA may not function in its original capacity as a foetal shunt but still retains smooth muscles cells until senescence. Ultra‐structurally, the presence of myofilaments, dense bodies and dense bands on smooth muscle cells (SMC) observed within the LA are findings compatible with the apparatus responsible for contraction in SMC. Furthermore, the presence of numerous mitochondria, a cellular organelle, and a potential site of calcium accumulation for smooth muscle contraction, observed within the LA may play a role in its contractility. Immunoreactivity to TH‐, NPY‐, SP‐, and CGRP‐ is suggestive of sympathetic and sensory innervation within the LA. Additionally, dose‐response contractility and relaxation of pre‐contracted LA to exogenous NA and ɑ1‐adrenergic antagonists in organ bath experiments suggests activity of ɑ1‐adrenoceptors. Conclusively, it is evident that LA is made up of contractile SMC with noradrenergic and sensory innervation. Its contractility may influence the compliance or impedance of the two major vascular segments to which the LA is attached.

The Dual Role of the β2-Adrenoreceptor in the Modulation of IL-17 and IFN-γ Production by T Cells in Multiple Sclerosis

Norepinephrine is a neurotransmitter that also has an immunomodulatory effect and is involved in multiple sclerosis (MS) pathogenesis. This study aimed to clarify the role of the β2-adrenoreceptor in the norepinephrine-mediated modulation of interleukin-17 (IL-17) and interferon-γ (IFN-γ) production, which play a critical pathogenetic role in MS. CD4+ T cells obtained from twenty-five relapsing-remitting MS patients and sixteen healthy subjects were cultured ex vivo with norepinephrine and/or β2-adrenoreceptor antagonist or agonist, followed by a cytokine production analysis using ELISA. Norepinephrine suppressed IL-17 and IFN-γ production by the anti-CD3/anti-CD28-microbead-stimulated CD4+ T cells in both groups. Blockade of the β2-adrenoreceptor with the specific antagonist ICI 118.551 enhanced norepinephrine-mediated IL-17 suppression but decreased its inhibitory effect on IFN-γ production in MS patients. In contrast, the β2-adrenoreceptor agonist formoterol did not influence norepinephrine’s inhibitory effect on cytokine production in both groups. The blockade of the β2-adrenoreceptor, even in the absence of exogenous norepinephrine, suppressed IL-17 production but did not influence IFN-γ production in both groups. Conversely, β2-adrenoreceptor activation by formoterol decreased IFN-γ production and did not affect IL-17 production in both groups. These data illustrate the inhibitory effect of norepinephrine on IL-17 and IFN-γ production by CD4+ T cells in MS. The inhibitory effect of norepinephrine on IFN-γ production by CD4+ T cells in MS could be mediated via β2-adrenoreceptor activation.

Reserpine improves Enterobacteriaceae resistance in chicken intestine via neuro-immunometabolic signaling and MEK1/2 activation

Salmonella enterica persist in the chicken gut by suppressing inflammatory responses via expansion of intestinal regulatory T cells (Tregs). In humans, T cell activation is controlled by neurochemical signaling in Tregs; however, whether similar neuroimmunological signaling occurs in chickens is currently unknown. In this study, we explore the role of the neuroimmunological axis in intestinal Salmonella resistance using the drug reserpine, which disrupts intracellular storage of catecholamines like norepinephrine. Following reserpine treatment, norepinephrine release was increased in both ceca explant media and Tregs. Similarly, Salmonella killing was greater in reserpine-treated explants, and oral reserpine treatment reduced the level of intestinal Salmonella Typhimurium and other Enterobacteriaceae in vivo. These antimicrobial responses were linked to an increase in antimicrobial peptide and IL-2 gene expression as well as a decrease in CTLA-4 gene expression. Globally, reserpine treatment led to phosphorylative changes in epidermal growth factor receptor (EGFR), mammalian target of rapamycin (mTOR), and the mitogen-associated protein kinase 2(MEK2). Exogenous norepinephrine treatment alone increased Salmonella resistance, and reserpine-induced antimicrobial responses were blocked using beta-adrenergic receptor inhibitors, suggesting norepinephrine signaling is crucial in this mechanism. Furthermore, EGF treatment reversed reserpine-induced antimicrobial responses, whereas mTOR inhibition increased antimicrobial activities, confirming the roles of metabolic signaling in these responses. Finally, MEK1/2 inhibition suppressed reserpine, norepinephrine, and mTOR-induced antimicrobial responses. Overall, this study demonstrates a central role for MEK1/2 activity in reserpine induced neuro-immunometabolic signaling and subsequent antimicrobial responses in the chicken intestine, providing a means of reducing bacterial colonization in chickens to improve food safety.

Comparative study of dexmedetomidine vs. midazolam on plasma catecholamine levels and hemodynamics in patients with septic shock

To compare the effects of dexmedetomidine (DEX) and midazolam on the endogenous plasma catecholamine levels and the dosage of exogenous norepinephrine (NE) to maintain blood pressure in patients with septic shock. From January 2018 to December 2019, patients admitted to the department of critical care medicine of the Affiliated Hospital of Guizhou Medical University who needed invasive mechanical ventilation and had a stay of more than 48 hours in the intensive care unit (ICU) for septic shock and received DEX or midazolam for sedation were enrolled in this study. The hemodynamic data, arterial blood lactic acid (Lac) level, arterial blood gas analysis and vasoactive drug dose at 0, 12, 24, 48, 72 hours after entering the ICU were dynamically recorded, and the plasma catecholamine levels at 0, 24, 48 hours after entering the ICU were recorded. The acute physiology and chronic health evaluation II (APACHE II) score and sequential organ failure assessment (SOFA) score on ICU-admission were calculated. The parameters of prognosis were collected. A total of 24 patients were enrolled, 12 in the DEX group and 12 in the midazolam group. There were similar dynamic trends in heart rate (HR), central venous pressure (CVP), venous-arterial carbon dioxide pressure difference (Pv-aCO2), oxygenation index (PaO2/FiO2), and Lac level of patients between the two groups. Only the 12-hour CVP and 72-hour Pv-aCO2 in the DEX group were significantly higher than those in the midazolam group [CVP (mmHg, 1 mmHg = 0.133 kPa): 13±3 vs. 10±3, Pv-aCO2 (mmHg): 9.4±5.2 vs. 4.8±2.2, both P < 0.05], and the mean arterial pressure (MAP) of patients in the DEX group at 48 hours and 72 hours was significantly higher than that in the midazolam group (mmHg: 95±10 vs. 86±10, 96±9 vs. 88±7, both P < 0.05). There was no statistically significant difference in the duration of mechanical ventilation, ICU mortality or in-hospital mortality between the DEX group and the midazolam group [duration of mechanical ventilation (days): 5.6 (3.8, 9.5) vs. 10.5 (5.9, 15.0), ICU mortality: 16.7% vs. 33.3%, in-hospital mortality: 25.0% vs. 41.7%, all P > 0.05]. There was no significant difference in the dosage of propofol or sufentanil between the DEX group and the midazolam group [propofol (mg/kg): 0 (0, 9.35) vs. 4.07 (0, 13.75), sufentanil (μg/kg): 6.26 (4.90, 9.80) vs. 8.32 (3.52, 9.34), both P > 0.05]. The levels of plasma NE, dopamine and dobutamine in the DEX group at 48 hours were significantly lower than those in the midazolam group [NE (ng/L): 1 850.12 (342.16, 2 938.05) vs. 4 596.60 (3 310.56, 5 546.84), dopamine (ng/L): 119.10 (60.47, 200.71) vs. 275.40 (214.61, 418.88), dobutamine (ng/L): 51.20 (36.85, 75.59) vs. 98.97 (85.65, 107.10), all P < 0.05], but the amount of NE required to maintain MAP between 65 mmHg and 75 mmHg in the DEX group and the midazolam group was similar [μg/kg: 1 922 (1 170, 4 887) vs. 2 466 (2 043, 3 438), P > 0.05]. DEX can reduce plasma catecholamine levels in patients with septic shock more than midazolam, and does not increase the dose of exogenous NE, and has a smaller effect on hemodynamics in patients with septic shock than midazolam.

Noradrenergic Profile of Hippocampal Formation Theta Rhythm in Anaesthetized Rats

The present study was undertaken to identify the noradrenergic receptors underlying the production of hippocampal formation (HPC) type 2 theta rhythm. The experiments were performed on urethanized rats wherein type 2 theta is the only rhythm present. In three independent stages of experiments, the effects of noradrenaline (NE) and selective noradrenergic α and β agonists and antagonists were tested. We indicate that the selective activation of three HPC noradrenergic receptors, α1, α2 and β1, induced a similar effect (i.e., inhibition) on type 2 theta rhythm. The remaining HPC β2 and β3 noradrenergic receptors do not seem to be directly involved in the pharmacological mechanism responsible for the suppression of theta rhythm in anaesthetized rats. Obtained results provide evidence for the suppressant effect of exogenous NE on HPC type 2 theta rhythm and show the crucial role of α1, α2 and β1 noradrenergic receptors in the modulation of HPC mechanisms of oscillations and synchrony. This finding is in contrast to the effects of endogenous NE produced by electrical stimulation of the locus coeruleus (LC) and procaine injection into the LC (Broncel et al., 2020).

Curcumin inhibits adverse psychological stress-induced proliferation and invasion of glioma cells via down-regulating the ERK/MAPK pathway.

Curcumin is a natural polyphenol extracted from the rhizome of Curcuma that has an important antitumour effect, but its effect on adverse psychological stress‐induced tumour proliferation and invasion has not been reported to date. Here, we found that curcumin not only inhibited the growth of xenografts in chronically stressed nude mice, but also decreased the expression of matrix metalloproteinase (MMP)‐2/9 and CD147 in tumour tissues. Exogenous norepinephrine (NE) was used to stimulate glioma cells to simulate the stress environment in vitro, and it was found that curcumin inhibited the NE‐induced proliferation and invasion of glioma cells in a dose‐dependent manner. Further research found that the effects of NE on glioma cells could lead to the activation of the mitogen‐activated protein kinase (MAPK) signalling pathway through β‐adrenergic receptor, while curcumin suppressed the level of extracellular signal–regulated kinase (ERK)1/2 phosphorylation. In addition, blocking ERK1/2 expression with U0126 resulted in the down‐regulated expression of CD147, which further led to the decreased expression of MMP‐2 and MMP‐9. Curcumin could also inhibit the expression of cyclin D1/CDK4/6 and anti‐apoptotic protein Bcl‐2/Bcl‐XL induced by NE, and induced cell cycle changes and increased apoptosis. Therefore, curcumin may be a potential candidate drug for preventing and treating the progression of glioma induced by adverse psychological stress.

Neurotoxicity of Olindias sambaquiensis and Chiropsalmus quadrumanus extracts in sympathetic nervous system

Cnidarians are equipped with nematocysts, which are specialized organelles used to inoculate venom during prey capturing and defense. Their venoms are rich in toxins and a potential source of bioactive compounds, however, poorly explored so far. In this work, the activity of the methanolic extracts from the hydromedusa Olindias sambaquiensis and the cubozoan jellyfish Chiropsalmus quadrumanus were studied in sympathetic neurotransmission. For that, bisected rat vas deferens - a classic model of sympathetic neurotransmission - were incubated with the extracts for further myographic and histopathological analysis. The O. sambaquiensis extract, at 0.1 μg/mL, facilitated the neurogenic contractions of the noradrenergic-rich epididymal portion, while reducing the noradrenaline (NA) potency, which suggests an interaction with postsynaptic α1-adrenoceptors. On the other hand, a higher concentration (1 μg/mL) leads to time- and frequency-dependent blockade of nerve-evoked contractions without significantly changing the response to exogenous NA. In turn, the C. quadrumanus extract at 0.1 μg/mL induced blockade of nerve-evoked noradrenergic contractions while reducing the potency to exogenous NA. Both extracts did not affect the purinergic neurotransmission or induce muscle damages. Our results demonstrate that O. sambaquiensis and C. quadrumanus extracts significantly interfere with the noradrenergic neurotransmission without altering purinergic response or smooth muscle structure on rat vas deferens. Such results bring to light the pharmacological potential of O. sambaquiensis and C. quadrumanus molecules for therapeutics focusing on noradrenergic neurotransmission.

Splenic Denervation Attenuates Repeated Social Defeat Stress-Induced T Lymphocyte Inflammation

BackgroundPosttraumatic stress disorder (PTSD) is a devastating psychological disorder. Patients with PTSD canonically demonstrate an increased risk for inflammatory diseases as well as increased sympathetic tone and norepinephrine outflow. Yet, the exact etiology and causal nature of these physiologic changes remain unclear. Previously, we demonstrated that exogenous norepinephrine alters mitochondrial superoxide in T lymphocytes to produce a proinflammatory T helper 17 phenotype and observed similar T helper 17 polarization in a preclinical model of PTSD. Therefore, we hypothesized sympathetic-driven neuroimmune interactions could mediate psychological trauma–induced T lymphocyte inflammation. MethodsRepeated social defeat stress (RSDS) is a preclinical murine model that recapitulates the behavioral, autonomic, and inflammatory aspects of PTSD. Targeted splenic denervation was performed to deduce the contribution of splenic sympathetic nerves to RSDS-induced inflammation. Denervation or sham operation was performed in 85 C57BL/6J mice, followed by RSDS or control paradigms. Animals were assessed for behavioral, autonomic, inflammatory, and redox profiles. ResultsDenervation did not alter the antisocial or anxiety-like behavior induced by RSDS. In circulation, denervation/RSDS animals exhibited diminished levels of T lymphocyte–specific cytokines (interleukin 2 [IL-2], IL-17A, and IL-22) compared with intact animals, whereas other nonspecific inflammatory cytokines (e.g., IL-6, tumor necrosis factor α, and IL-10) were unaffected by denervation. Importantly, denervation specifically ameliorated the increases in RSDS-induced T lymphocyte mitochondrial superoxide, T helper 17 polarization, and proinflammatory gene expression with minimal impact to non–T lymphocyte immune populations. ConclusionsOverall, our data suggest that sympathetic nerves regulate RSDS-induced splenic T lymphocyte inflammation but play less of a role in the behavioral and non–T lymphocyte inflammatory phenotypes induced by this psychological trauma paradigm.

Resting cardiac sympathetic firing frequencies suppress terminal norepinephrine transporter uptake.

The prejunctional norepinephrine transporter (NET) is responsible for the clearance of released norepinephrine (NE) back into the sympathetic nerve terminal. NET regulation must be tightly controlled as variations could have important implications for neurotransmission. Thus far, the effects of sympathetic neuronal activity on NET function have been unclear. Here, we optically monitor single-terminal cardiac NET activity ex vivo in response to a broad range of sympathetic postganglionic action potential (AP) firing frequencies. Isolated murine left atrial appendages were loaded with a fluorescent NET substrate [Neurotransmitter Transporter Uptake Assay (NTUA)] and imaged with confocal microscopy. Sympathetic APs were induced with electrical field stimulation at 0.2-10 Hz (0.1-0.2 ms pulse width). Exogenous NE was applied during the NTUA uptake- and washout phases to investigate substrate competition and displacement, respectively, on transport. Single-terminal NET reuptake rate was rapidly suppressed in a frequency-dependent manner with an inhibitory EF50 of 0.9 Hz. At 2 Hz, the effect was reversed by the α2-adrenoceptor antagonist yohimbine (1 μM) (p < 0.01) with no further effect imposed by the muscarinic receptor antagonist atropine (1 μM). Additionally, high exogenous NE concentrations abolished NET reuptake (1 μM NE; p < 0.0001) and displaced terminal specific NTUA during washout (1-100 μM NE; p < 0.0001). We have also identified α2-adrenoceptor-induced suppression of NET reuptake rate during resting stimulation frequencies, which could oppose the effect of autoinhibition-mediated suppression of exocytosis and thus amplify the effects of sympathetic drive on cardiac function.

Sympathetic Nerves Control Splenic T-Lymphocyte Inflammation and the Mitochondrial Redox Environment During Repeated Social Defeat Stress

Post-traumatic stress disorder (PTSD) is a devastating psychological disorder that increases the risk for autoimmune disease by >3 fold, with the exact etiology still unclear. A known hallmark of PTSD is increased sympathetic tone and norepinephrine (NE) outflow. We have previously demonstrated that exogenous NE induces a pro-inflammatory T-helper 17 (TH17) phenotype in T-lymphocytes through a mitochondrial superoxide-dependent manner. Therefore, we hypothesized sympathetic-driven neuroimmune interactions could mediate psychological trauma-induced T-lymphocyte inflammation.

ROSTAFUROXIN RESTORES THE INCREASED PERIVASCULAR INNERVATION IN RESISTANCE ARTERIES OF HYPERTENSIVE RATS

Objective: Ouabain (OUA) inhibiting Na+, K+-ATPase (NKA) activity modulates neurotransmitter release from perivascular innervation (PVI). However, the role of OUA on PVI through NKA/cSRC signalosome pathway is unknown. Thus, we investigated the role of rostafuroxin (ROSTA) treatment, an OUA signalosome pathway antagonist, on PVI of mesenteric resistance arteries (MRAs) from deoxycorticosterone acetate-salt (DOCA-salt) hypertensive rats, mainly on sympathetic and nitrergic PVI participation. Design and method: Five-week after DOCA-salt treatment, rats were allocated into two groups: DOCA-salt treated with ROSTA (1 mg/kg per day gavage, 3 weeks) or vehicle. Male, Wistar rats uninephrectomized were used as normal control (NC). Systolic blood pressure (SBP) was measured weekly by tail-cuff method. Electric field stimulation (EFS), noradrenaline (NA) and sodium nitroprusside (SNP) response-curves were evaluated in isolated MRA without endothelium. Results: ROSTA treatment decreased SBP (42%) compared to DOCA-salt. EFS induced contractile response in MRAs of all groups, while this response was higher in DOCA-salt compared to NC or ROSTA group. EFS-induced contraction was reduced in the presence of alfa-adrenoceptor antagonist (phentolamine, PNT) in all groups, whereas this contractile response was blocked by the association between PNT and suramin (P2-purinergic receptor antagonist) only in NC and ROSTA groups. L-NAME enhanced the contraction induced by EFS; however, this effect was smaller in DOCA-salt rings compared to NC and ROSTA. EFS-induced contraction was abolished in MRAs preincubated with tetrodotoxin (voltage-dependent sodium channel blocker). On the other hand, concentration–response curves to exogenous NA and SNP were unmodified among groups. Conclusions: ROSTA treatment was able to reduce perivascular sympathetic innervation and to increase nitrergic innervation on the contractile response to EFS in MRAs of DOCA-salt rats. These modifications might contribute to the beneficial effects of OUA/NKA/cSRC pathway antagonism on volume-dependent hypertension.

Psychological Stress Up-Regulates CD147 Expression Through Beta-Arrestin1/ERK to Promote Proliferation and Invasiveness of Glioma Cells.

Psychological stress is closely related to the occurrence and prognosis of various malignant tumors, but the underlying mechanisms are not well studied. CD147 has been reported to be expressed in glioma and other malignant tumors. CD147 not only participates in lactic acid transport, but it also plays an important role in the invasion and metastasis of malignant tumor cells by stimulating the production of numerous matrix metalloproteinases (MMPs) and vascular endothelial growth factor by fibroblasts, and could also act as an autocrine factor stimulating MMPs production in metastatic tumor cells. Here, we found that silencing CD147 in chronically stressed nude mice not only inhibited the proliferation of xenografts but also decreased matrix metalloproteinase-2, 9 expression and lactic acid content in tumor tissues. Furthermore, norepinephrine (NE) was significantly increased in the serum of nude mice in glioma stress model. To determine the underlying cellular mechanism, we added exogenous NE into LN229 and U87 cells to simulate the stress environment in vitro. The invasiveness of the glioma cells was subsequently examined using a Matrigel invasion assay. We demonstrated that knockdown of CD147 inhibited glioma invasiveness and metastasis with norepinephrine stimulation. Luciferase reporter gene experiments further demonstrated that the expression of CD147 is up-regulated primarily by norepinephrine via the β-Adrenalin receptor (βAR)-β-arrestin1-ERK1/2-Sp1 pathway. High expression of CD147 promoted the secretion of MMP-2 and the increment of lactic acid, which accelerated the augmented invasion and metastasis of glioma induced by psychological stress. Taken together, these results suggest that psychological stress promotes glioma proliferation and invasiveness by up-regulating CD147 expression. Thus, CD147 might be a potential target site in the treatment of glioma progression induced by chronic psychological stress.