Roles of the α1B-Adrenergic Receptor Phosphorylation Domains in Signaling and Internalization.

The function of the α1B-adrenergic receptor phosphorylation sites previously detected by mass spectrometry was evaluated by employing mutants, substituting them with non-phosphorylatable amino acids. Substitution of the intracellular loop 3 (IL3) sites did not alter baseline or stimulated receptor phosphorylation, whereas substitution of phosphorylation sites in the carboxyl terminus (Ctail) or both domains (IL3/Ctail) markedly decreased receptor phosphorylation. Cells expressing the IL3 or Ctail receptor mutants exhibited a noradrenaline-induced calcium-maximal response similar to those expressing the wild-type receptor, and a shift to the left in the concentration-response curve to noradrenaline was also noticed. Cells expressing the IL3/Ctail mutant exhibited higher apparent potency and increased maximal response to noradrenaline than those expressing the wild-type receptor. Phorbol ester-induced desensitization of the calcium response to noradrenaline was reduced in cells expressing the IL3 mutant and abolished in cells in which the Ctail or the IL3/Ctail were modified. In contrast, desensitization in response to preincubation with noradrenaline was unaffected in cells expressing the distinct receptor mutants. Noradrenaline-induced ERK phosphorylation was surprisingly increased in cells expressing IL3-modified receptors but not in those expressing receptors with the Ctail or IL3/Ctail substitutions. Our data indicate that phosphorylation sites in the IL3 and Ctail domains mediate and regulate α1B-adrenergic receptor function. Phorbol ester-induced desensitization seems to be closely associated with receptor phosphorylation, whereas noradrenaline-induced desensitization likely involves other elements.

Dexmedetomidine Preconditioning Attenuates Myocardial Ischemia/Reperfusion Injury in Rats by Suppressing Mitophagy Via Activating Α2-Adrenergic Receptor. / O Pré-Condicionamento com Dexmedetomidina Atenua a Lesão de Isquemia/Reperfusão Miocárdica em Ratos, Suprimindo a Mitofagia Via Ativação do Receptor Α2-Adrenérgico.

BACKGROUND: Dexmedetomidine (DEX), a specific α2-adrenergic receptor agonist, is protective against myocardial ischemia/reperfusion injury (MIRI). However, the association between DEX preconditioning-induced cardioprotection and mitophagy suppression remains unclear. OBJECTIVE: Hence, we aimed to investigate whether DEX preconditioning alleviates MIRI by suppressing mitophagy via α2-adrenergic receptor activation. METHOD: Sixty isolated rat hearts were treated with or without DEX before inducing ischemia and reperfusion; an α2-adrenergic receptor antagonist, yohimbine (YOH), was also administered before ischemia, alone or with DEX. The heart rate (HR), left ventricular diastolic pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), maximal and minimal rate of left ventricular pressure development (±dp/dtmax), and myocardial infarction size were measured. The mitochondrial ultrastructure and autophagosomes were assessed using transmission electron microscopy. Mitochondrial membrane potential and reactive oxygen species (ROS) levels were measured using JC-1 and dichloride hydrofluorescein diacetate assays, respectively. The expression levels of the mitophagy-associated proteins Beclin1, LC3II/I ratio, p62, PINK1, and Parkin were detected by western blotting. RESULTS: Compared with the control group, in the ischemia/reperfusion group, the HR, LVDP, and ±dp/dtmax were remarkably decreased (p< 0.05), whereas LVEDP and infarct sizes were significantly increased (p< 0.05). DEX preconditioning significantly improved cardiac dysfunction reduced myocardial infarction size, maintained mitochondrial structural integrity, increased mitochondrial membrane potential, inhibited autophagosomes formation, and decreased ROS production and Beclin1, LC3II/I ratio, PINK1, Parkin, and p62 expression(p< 0.05). When DEX and YOH were combined, YOH canceled the effect of DEX, whereas the use of YOH alone had no effect. CONCLUSION: Therefore, DEX preconditioning was cardioprotective against MIRI in rats by suppressing mitophagy via α2-adrenergic receptor activation.

FUNDAMENTO: A dexmedetomidina (DEX), um agonista específico do receptor α2-adrenérgico, é protetora contra lesão de isquemia/reperfusão miocárdica (I/R). No entanto, a associação entre a cardioproteção induzida pelo pré-condicionamento DEX e a supressão da mitofagia permanece pouco clara. OBJETIVO: Portanto, nosso objetivo foi investigar se o pré-condicionamento com DEX alivia a I/R, suprimindo a mitofagia via ativação do receptor α2-adrenérgico. MÉTODO: Sessenta corações de ratos isolados foram tratados com ou sem DEX antes de induzir isquemia e reperfusão; um antagonista do receptor α2-adrenérgico, a ioimbina (YOH), também foi administrado antes da isquemia, isoladamente ou com DEX. A frequência cardíaca (FC), pressão diastólica do ventrículo esquerdo (PDVE), pressão diastólica final do ventrículo esquerdo (PDFVE), taxa máxima e mínima de desenvolvimento da pressão ventricular esquerda (±dp/dtmax) e tamanho do infarto do miocárdio foram medidos. A ultraestrutura mitocondrial e as autofagossomas foram avaliadas por microscopia eletrônica de transmissão. O potencial de membrana mitocondrial e os níveis de espécies reativas de oxigênio (ROS) foram medidos usando os ensaios JC-1 e diacetato de diclorodi hidrofluoresceína, respectivamente. Os níveis de expressão das proteínas associadas à mitofagia Beclin1, relação LC3II/I, p62, PINK1 e Parkin foram detectados por western blotting. RESULTADOS: Em comparação com o grupo controle, no grupo isquemia/reperfusão, a FC, PDVE e ±dp/dtmax foram notavelmente diminuídas (p<0,05), enquanto os tamanhos da PDFVE e do infarto aumentaram significativamente (p<0,05). O pré-condicionamento com DEX melhorou significativamente a disfunção cardíaca, reduziu o tamanho do infarto do miocárdio, manteve a integridade estrutural mitocondrial, aumentou o potencial de membrana mitocondrial, inibiu a formação de autofagossomas e diminuiu a produção de ROS e a relação Beclin1, relação LC3II/I, expressão PINK1, Parkin e p62(p<0,05). Quando DEX e YOH foram combinados, o YOH cancelou o efeito da DEX, enquanto o uso de YOH sozinha não teve efeito. CONCLUSÃO: Portanto, o pré-condicionamento DEX foi cardioprotetor contra I/R em ratos, suprimindo a mitofagia por meio da ativação do receptor α2-adrenérgico.

Thyroid hormone induces restrictive cardiomyopathy in ß1-adrenoceptor knockout mice.

The purpose of this study was to characterize the role of ß1-AR signaling and its cross-talk between cardiac renin-angiotensin system and thyroid-hormone-induced cardiac hypertrophy. T3 was administered at 0.5 mg·kg-1·day-1 for 10 days in ß1-KOT3 and WTT3 groups, while control groups received vehicle alone. Echocardiography and myocardial histology was performed; cardiac and serum ANGI/ANGII and ANP and cardiac levels of p-PKA, p-ERK1/2, p-p38-MAPK, p-AKT, p-4EBP1, and ACE were measured. WTT3 showed decreased IVSTd and increased LVEDD versus WTsal (p < 0.05). ß1-KOT3 exhibited lower LVEDD and higher relative IVSTd versus ß1-KOsal, the lowest levels of ejection fraction, and the highest levels of cardiomyocyte diameter (p < 0.05). Cardiac ANP levels decreased in WTT3 versus ß1-KOT3 (p < 0.05). Cardiac ACE expression was increased in T3-treated groups (p < 0.05). Phosphorylated-p38 MAPK levels were higher in WTT3 versus WTsal or ß1-KOT3, p-4EBP1 was elevated in ß1-KO animals, and p-ERK1/2 was up-regulated in ß1-KOT3. These findings suggest that ß1-AR signaling is crucial for TiCH.

Impact of the cAMP efflux and extracellular cAMP-adenosine pathway on airway smooth muscle relaxation induced by formoterol and phosphodiesterase inhibitors.

ß2-adrenoceptors agonists and phosphodiesterase (PDE) inhibitors are effective bronchodilators, due to their ability to increase intracellular cyclic AMP (cAMP) levels and induce airway smooth muscle (ASM) relaxation. We have shown that increment of intracellular cAMP induced by ß2-adrenoceptors agonist fenoterol is followed by efflux of cAMP, which is converted by ecto-PDE and ecto-5'-nucleotidases (ecto-5'NT) to adenosine, leading to ASM contraction. Here we evaluate whether other classical bronchodilators used to treat asthma and chronic obstructive pulmonary disease (COPD) could induce cAMP efflux and, as consequence, influence the ASM contractility. Our results showed that ß2-adrenoceptor agonists formoterol and PDE inhibitors IBMX, aminophylline and roflumilast induced cAMP efflux and a concentration-dependent relaxation of rat trachea precontracted with carbachol. Pretreatment of tracheas with MK-571 (MRP transporter inhibitor), AMP-CP (ecto-5'NT inhibitor) or CGS-15943 (nonselective adenosine receptor antagonist) potentiated the relaxation induced by ß2-adrenoceptor agonists but did not change the relaxation induced by PDE inhibitors. These data showed that all bronchodilators tested were able to induce cAMP efflux. However, only ß2-adrenoceptor-induced relaxation of tracheal smooth muscle was affected by cAMP efflux and extracellular cAMP-adenosine pathway.

Effects of Adrenergic Receptor Stimulation on Human Hemostasis: A Systematic Review.

Catecholamine stimulation over adrenergic receptors results in a state of hypercoagulability. Chronic stress involves the release and increase in circulation of catecholamines and other stress related hormones. Numerous observational studies in human have related stressful scenarios to several coagulation variables, but controlled stimulation with agonists or antagonists to adrenergic receptors are scarce. This systematic review is aimed at presenting an updated appraisal of the effect of adrenergic receptor modulation on variables related to human hemostasis by systematically reviewing the effect of adrenergic receptor-targeting drugs on scale variables related to hemostasis. By searching 3 databases for articles published between January 1st 2011 and February 16th, 2022 reporting effects on coagulation parameters from stimulation with α- or ß-adrenergic receptor targeting drugs in humans regardless of baseline condition, excluding records different from original research and those not addressing the main aim of this systematic review. Risk of bias assessed using the Revised Cochrane risk-of-bias tool for randomized trials (RoB 2). Tables describing a pro-thrombotic anti-fibrinolytic state induced after ß-adrenergic receptor agonist stimulation and the opposite after α1-, ß-adrenergic receptor antagonist stimulation were synthesized from 4 eligible records by comparing hemostasis-related variables to their baseline. Notwithstanding this low number of records, experimental interventions included were sound and mostly unbiased, results were coherent, and outcomes were biologically plausible. In summary, this systematic review provides a critical systematic assessment and an updated elaboration, and its shortcomings highlight the need for further investigation in the field of hematology.

6-Nitrodopamine potentiates contractions of rat isolated vas deferens induced by noradrenaline, adrenaline, dopamine and electric field stimulation.

6-Nitrodopamine (6-ND) is a novel endogenous catecholamine that is released from the rat isolated vas deferens, and has been characterized as a major modulator of the contractility of rat isolated epididymal vas deferens (RIEVD). Drugs such as tricyclic antidepressants, α1 and ß1ß2 adrenoceptor blockers, act as selective antagonists of the 6-ND receptor in the RIEVD. In the rat isolated atria, 6-ND has a potent positive chronotropic action and causes remarkable potentiation of the positive chronotropic effects induced by dopamine, noradrenaline, and adrenaline. Here, whether 6-ND interacts with the classical catecholamines in the rat isolated vas deferens was investigated. Incubation with 6-ND (0.1 and 1 nM; 30min) caused no contractions in the RIEVD but provoked significant leftward shifts in the concentration-response curves to noradrenaline, adrenaline, and dopamine. Pre-incubation of the RIEVD with 6-ND (1 nM), potentiated the contractions induced by electric-field stimulation (EFS), whereas pre-incubation with 1 nM of dopamine, noradrenaline or adrenaline, did not affect EFS-induced contractions. In tetrodotoxin (1 µM) pre-treated (30 min) RIEVD, pre-incubation with 6-ND (0.1 nM) did not cause leftward shifts in the concentration-dependent contractions induced by noradrenaline, adrenaline, or dopamine. Pre-incubation of the RIEVD with the α2A-adrenoceptor antagonist idazoxan (30 min, 10 nM) did not affect dopamine, noradrenaline, adrenaline, and EFS-induced contractions. However, when idazoxan (10 nM) and 6-ND (0.1 nM) were simultaneously pre-incubated (30 min), a significant potentiation of the EFS-induced contractions of the RIEVD was observed. 6-nitrodopamine causes remarkable potentiation of dopamine, noradrenaline, and adrenaline contractions on the RIEVD, due to activation of adrenergic terminals, possibly via pre-synaptic adrenoceptors.

Antidepressant- and anxiolytic-like actions of Cajanus cajan seed extract mediated through monoaminergic, nitric oxide-cyclic GMP and GABAergic pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: The seeds of Cajanus cajan (L) Millsp, are used in Traditional medicine for the treatment of anxiety and other neurological disorders. Hence, this study is designed to investigate the antidepressant- and anxiolytic-like properties of ethanol seed extract of Cajanus cajan (CC) in mice. MATERIALS AND METHODS: CC (50, 100 or 200 mg/kg, p.o.) was administered 1h before subjecting the animals to different behavioral models: forced swim test (FST) and tail suspension test (TST) (depressive-like behaviour), open field test (OFT), elevated plus maze (EPM), light-dark test (LDT) and hole-board test (HBT) for anxiety-like behaviour. To ascertain the pharmacodynamic of CC mice were pretreated with monoaminergic, nitrergic and GABAergic receptors antagonists. As well as molecular docking analysis of about 19 flavonoids present in CC on GABAA, α2 adrenoceptors and 5-HT2A receptors. RESULTS: CC (50, 100 or 200 mg/kg, p.o.) treatment significantly reduced immobile time in both FST and TST when compared with vehicle-treated control. However, the pretreatment of mice with prazosin/yohimbine (α1/2 adrenoceptor antagonists, respectively), WAY100635 (5-HT1A receptor antagonist), ketanserin (5-HT2A receptor antagonist), sulpiride (dopamine D2 receptor antagonist), L-NG-Nitro arginine methyl ester (L-NAME), or methylene blue reversed the antidepressant-like effect of CC. In anxiety model, CC produced significant (p < 0.05) increase in open arms exploration and head dipping behavior which was reversed by flumazenil (benzodiazepine receptor antagonist) in the EPM. Docking analysis showed significant binding affinity of orientin, vitexin, pinostrobin and quercetin with 5HT2A, α2-adrenoceptor and GABAA receptors. CONCLUSION: Findings from this study showed that C.cajan seeds extract exerts antidepressant-like effect through participation of monoaminergic systems (5-HT2 receptor, α1/α2-adrenoceptors, and dopamine D2-receptors), nitric oxide-cyclic GMP pathway and anxiolytic-like effect via GABAA benzodiazepine receptors. Moreso, presence of flavonoids with significant binding energies with monoaminergic and GABAergic systems support the potential of the extract in the management of mixed anxiety-depressive illness.

Adrenergic receptors in breast cancer.

Breast cancer is the most diagnosed malignancy in women worldwide and in the majority of the countries. Breast cancers are classified on the expression of estrogen and progesterone receptor expression and overexpression of human epidermal growth factor receptor 2 (HER2) as luminal, HER2+ and triple negative breast cancer. The intrinsic molecular subtypes match this classification. Cancer diagnosis and treatment cause distress. In both acute and chronic stress, the secreted catecholamines adrenaline and noradrenaline trigger the "fight-or-flight" response. This chapter focuses on the actions of the ß2 and α2 adrenergic receptors in several models of breast cancer. The actions of these receptors depend on the model used to investigate them. The ß2-adrenergic receptors seem to exert a dual action. They can directly act on the epithelial cells inhibiting cell proliferation and migration/invasion and indirectly upon the immune microenvironment. The proportion of ß2 receptors in each compartment could, therefore, lean the scale to an inhibition or to an exacerbation of tumor growth, invasion and metastasis. All the work points to a beneficial or neutral action of ß-blockers on breast cancer. With respect to α2-adrenergic receptors, the investigation performed by our group suggest that the α2B and the α2C receptors are linked to enhanced cell proliferation and tumor growth acting through both the epithelial and the stromal (fibroblastic) compartments while α2A could be beneficial for patients. Some adrenergic compounds could be repurposed for breast cancer treatment due to their very low side effects and very well-known pharmacology.

6-nitrodopamine is a major endogenous modulator of human vas deferens contractility.

BACKGROUND: Rat isolated vas deferens releases 6-nitrodopamine (6-ND), and the spasmogenic activity of this novel catecholamine is significantly reduced by tricyclic compounds such as amitriptyline, desipramine, and carbamazepine and by antagonists of the α1 -adrenergic receptors such as doxazosin, tamsulosin, and prazosin. OBJECTIVES: To investigate the liberation of 6-ND by human epididymal vas deferens (HEVDs) and its pharmacological actions. METHODS: The in vitro liberation of 6-ND, dopamine, noradrenaline, and adrenaline from human vas deferens was evaluated by LC-MS/MS. The contractile effect of the catecholamines in HEVDs was investigated in vitro. The action of tricyclic antidepressants was evaluated on the spasmogenic activity ellicited by the catecholamines and by the electric-field stimulation (EFS). The tissue was also incubated with the inhibitor of nitric oxide (NO) synthase L-NAME and the release of catecholamines and the contractile response to EFS were assessed. RESULTS: 6-ND is the major catecholamine released from human vas deferens and its synthesis/release is inhibited by NO inhibition. The spasmogenic activity elicited by EFS in the human vas deferens was blocked by tricyclic antidepressants only at concentrations that selectively antagonize 6-ND induced contractions of the human vas deferens, without affecting the spasmogenic activity induced by dopamine, noradrenaline, and adrenaline in this tissue. Incubation of the vas deferens with L-NAME reduced both the 6-ND release and the contractions induced by EFS. DISCUSSION AND CONCLUSION: 6-ND should be considered a major endogenous modulator of human vas deferens contractility and possibly plays a pivotal role in the emission process of ejaculation. It offers a novel and shared mechanism of action for tricyclic antidepressants and α1 -adrenergic receptor antagonists.

6-NitroDopamine is an endogenous modulator of rat heart chronotropism.

6-Nitrodopamine (6-ND) is released by rat vas deferens and exerts a potent contractile response that is antagonized by tricyclic antidepressants and α1-, ß1- and ß1/ß2-adrenoceptor antagonists. The release of 6-ND, noradrenaline, adrenaline and dopamine from rat isolated right atria was assessed by tandem mass spectrometry. The effects of the catecholamines were evaluated in both rat isolated right atria and in anaesthetized rats. 6-ND was the major catecholamine released from the isolated atria and the release was significantly reduced in nitric oxide synthase inhibitor L-NAME pre-treated atria or in atria obtained from L-NAME chronically treated animals, but unaffected by tetrodotoxin. 6-ND (1 pM) significantly increased the atrial frequency, being 100 times more potent than noradrenaline and adrenaline. Selective ß1-blockers reduced the atrial frequency only at concentrations that prevented the increases in atrial frequency induced by 6-ND 1pM. Conversely, ß1-blockade did not affect dopamine (10 nM), noradrenaline (100 pM) or adrenaline (100 pM) effect. The reductions in atrial frequency induced by the ß1-adrenoceptor antagonists were absent in L-NAME pre-treated atria and in atria obtained from chronic L-NAME-treated animals. Tetrodotoxin did not prevent the reduction in atrial frequency induced by L-NAME or by ß1-blockers treated preparations. In anaesthetized rats, at 1 pmol/kg, only 6-ND caused a significant increase in heart rate. Inhibition of 6-ND synthesis by chronic L-NAME treatment reduced both atrial frequency and heart rate. The results indicate that 6-ND is a major modulator of rat heart chronotropism and the reduction in heart rate caused by ß1-blockers are due to selective blockade of 6-ND receptor.

Extracellular cAMP-Adenosine Pathway Signaling: A Potential Therapeutic Target in Chronic Inflammatory Airway Diseases.

Adenosine is a purine nucleoside that, via activation of distinct G protein-coupled receptors, modulates inflammation and immune responses. Under pathological conditions and in response to inflammatory stimuli, extracellular ATP is released from damaged cells and is metabolized to extracellular adenosine. However, studies over the past 30 years provide strong evidence for another source of extracellular adenosine, namely the "cAMP-adenosine pathway." The cAMP-adenosine pathway is a biochemical mechanism mediated by ATP-binding cassette transporters that facilitate cAMP efflux and by specific ectoenzymes that convert cAMP to AMP (ecto-PDEs) and AMP to adenosine (ecto-nucleotidases such as CD73). Importantly, the cAMP-adenosine pathway is operative in many cell types, including those of the airways. In airways, ß2-adrenoceptor agonists, which are used as bronchodilators for treatment of asthma and chronic respiratory diseases, stimulate cAMP efflux and thus trigger the extracellular cAMP-adenosine pathway leading to increased concentrations of extracellular adenosine in airways. In the airways, extracellular adenosine exerts pro-inflammatory effects and induces bronchoconstriction in patients with asthma and chronic obstructive pulmonary diseases. These considerations lead to the hypothesis that the cAMP-adenosine pathway attenuates the efficacy of ß2-adrenoceptor agonists. Indeed, our recent findings support this view. In this mini-review, we will highlight the potential role of the extracellular cAMP-adenosine pathway in chronic respiratory inflammatory disorders, and we will explore how extracellular cAMP could interfere with the regulatory effects of intracellular cAMP on airway smooth muscle and innate immune cell function. Finally, we will discuss therapeutic possibilities targeting the extracellular cAMP-adenosine pathway for treatment of these respiratory diseases.

Muscle Stem Cell Function Is Impaired in ß2-Adrenoceptor Knockout Mice.

Knockout (ko) mice for the ß2 adrenoceptor (Adrß2) have impaired skeletal muscle regeneration, suggesting that this receptor is important for muscle stem cell (satellite cell) function. Here, we investigated the role of Adrß2 in the function of satellite cells from ß2ko mice in the context of muscle regeneration, through in vivo and in vitro experiments. Immunohistochemical analysis showed a significant reduction in the number of self-renewed Pax7+ satellite cells, proliferating Pax7+/MyoD+ myogenic precursor cells, and regenerating eMHC+ myofibers in regenerating muscle of ß2ko mice at 30, 3, and 10 days post-injury, respectively. Quiescent satellite cells were isolated by fluorescence-activated cell sorting, and cell cycle entry was assessed by EdU incorporation. The results demonstrated a lower number of proliferating Pax7+/EdU+ satellite cells from ß2ko mice. There was an increase in the gene expression of the cell cycle inhibitor Cdkn1a and Notch pathway components and the activation of Notch signaling in proliferating myoblasts from ß2ko mice. There was a decrease in the number of myogenin-positive nuclei in myofibers maintained in differentiation media, and a lower fusion index in differentiating myoblasts from ß2ko mice. Furthermore, the gene expression of Wnt/ß-catenin signaling components, the expression of nuclear ß-catenin and the activation of Wnt/ß-catenin signaling decreased in differentiating myoblasts from ß2ko mice. These results indicate that Adrß2 plays a crucial role in satellite cell self-renewal, as well as in myoblast proliferation and differentiation by regulating Notch and Wnt/ß-catenin signaling, respectively.

Antinociception Induced by Moringa Stenopetela (Baker f.) Cufod. Leaves Extract and Possible Mechanisms of Action

Moringa stenopetala (Baker f.) Cufod., is an endemic species growing in the south of Ethiopia. M. stenopetala is often consumed as food and used in traditional medicine and it has also been traditionally used for relieving of pain in Ethiopia. This study aimed to investigate the antinociceptive effect and mechanisms of action of M. stenopetala leaves methanol extract in mice. The per-oral doses of 50, 100, and 200 mg/kg of M. stenopetala extract were tested for antinociceptive action by using hot-plate, tail-immersion, and writhing tests. The possible mechanisms of in the antinociceptive action were investigated by pre-treatment with 5 mg/kg naloxone (non-selective opioid antagonist), 1 mg/kg ketanserin (5-HT2A/2C receptor antagonist), and 1 mg/kg yohimbine (α2 adrenoceptor antagonist). The methanol extract of M. stenopetala showed antinociceptive effect in all tests. The significant involvement of 5-HT2A/2C receptors and α2 adrenoceptors in antinociception induced by M. stenopetala extract in the hot-plate and tail-immersion tests, as well as significant contribution of opioid receptors and α2 adrenoceptors in writhing test, were identified. In conclusion, these findings demonstrate that the methanol extract of M. stenopetala has potential in pain management. Thisstudywillcontributetonewtherapeuticapproachesandprovideguidancefornewdrug development studies.

Nerve Growth Factor: A Dual Activator of Noradrenergic and Cholinergic Systems of the Rat Ovary.

The functioning of the ovary is influenced by the autonomic system (sympathetic and cholinergic intraovarian system) which contributes to the regulation of steroid secretion, follicular development, and ovulation. There is no information on the primary signal that activates both systems. The nerve growth factor (NGF) was the first neurotrophic factor found to regulate ovarian noradrenergic neurons and the cholinergic neurons in the central nervous system. The aim of this study was to determine whether NGF is one of the participating neurotrophic factors in the activation of the sympathetic and cholinergic system of the ovary in vivo and its role in follicular development during normal or pathological states. The administration of estradiol valerate (a polycystic ovary [PCO] phenotype model) increased norepinephrine (NE) (through an NGF-dependent mechanism) and acetylcholine (ACh) levels. Intraovarian exposure of rats for 28 days to NGF (by means of an osmotic minipump) increased the expression of tyrosine hydroxylase and acetylcholinesterase (AChE, the enzyme that degrades ACh) without affecting enzyme activity but reduced ovarian ACh levels. In vitro exposure of the ovary to NGF (100 ng/ml for 3 h) increased both choline acetyl transferase and vesicular ACh transporter expression in the ovary, with no effect in ACh level. In vivo NGF led to an anovulatory condition with the appearance of follicular cysts and decreased number of corpora lutea (corresponding to noradrenergic activation). To determine whether the predominance of a NE-induced polycystic condition after NGF is responsible for the PCO phenotype, rats were exposed to an intraovarian administration of carbachol (100 µM), a muscarinic cholinergic agonist not degraded by AChE. Decreased the number of follicular cysts and increased the number of corpora lutea, reinforcing that cholinergic activity of the ovary participates in controlling its functions. Although NGF increased the biosynthetic capacity for ACh, it was not available to act in the ovary. Hence, NGF also regulates the ovarian cholinergic system, implying that NGF is the main regulator of the dual autonomic control. These findings highlight the need for research in the treatment of PCO syndrome by modification of locally produced ACh as an in vivo regulator of follicular development.

Multiple cellular targets involved in the antidepressant-like effect of glutathione.

A previous study demonstrated that glutathione (GSH) produces specific antidepressant-like effect in the forced swimming test (FST), a predictive test of antidepressant activity. The present study investigated the involvement of multiple cellular targets implicated in the antidepressant-like effect of GSH in the FST. The antidepressant-like effect of GSH (300 nmol/site, icv) lasted up to 3 h when mice were submitted to FST. The central administration of oxidized GSH (GSSG, 3-300 nmol/site) did not alter the behavior of mice submitted to the FST. Furthermore, the combined treatment of sub-effective doses of GSH (100 nmol/site, icv) with a sub-effective dose of classical antidepressants (fluoxetine 10 mg/kg, and imipramine 5 mg/kg, ip) presented synergistic effect by decreasing the immobility time in the FST. The antidepressant-like effect of GSH was abolished by prazosin (1 mg/kg, ip, α1-adrenoceptor antagonist), baclofen (1 mg/kg, ip, GABAB receptor agonist), bicuculline (1 mg/kg, ip, GABAA receptor antagonist), l-arginine (750 mg/kg, ip, NO precursor), SNAP (25 µg/site, icv, NO donor), but not by yohimbine (1 mg/kg, ip, α2-adrenoceptor antagonist). The NMDA receptor antagonists, MK-801(0.001 mg/kg, ip) or GMP (0.5 mg/kg, ip), potentiated the effect of a sub-effective dose of GSH in the FST. These results suggest that the antidepressant-like effect induced by GSH is connected to the activation of α1 adrenergic and GABAA receptors, as well as the inhibition of GABAB and NMDA receptors and NO biosyntesis. We speculate that redox-mediated signaling on the extracelular portion of cell membrane receptors would be a common mechanism of action of GSH.

Ser49Gly Beta1-Adrenergic Receptor Genetic Polymorphism as a Death Predictor in Brazilian Patients with Heart Failure. / O Polimorfismo Genético do Receptor Beta-Adrenérgico Tipo 1 Ser49Gly é Preditor de Morte em Pacientes Brasileiros com Insuficiência Cardíaca.

Background The role of Ser49Gly beta1-adrenergic receptor genetic polymorphism (ADBR1-GP-Ser49Gly) as a predictor of death in heart failure (HF) is not established for the Brazilian population. Objectives To evaluate the association between ADBR1-GP-Ser49Gly and clinical outcomes in individuals with HF with reduced ejection fraction. Methods Secondary analysis of medical records of 178 patients and genotypes of GPRß1-Ser49Gly variants, classified as Ser-Ser, Ser-Gly and Gly-Gly. To evaluate their association with clinical outcome. A significance level of 5% was adopted. Results Cohort means were: clinical follow-up 6.7 years, age 63.5 years, 64.6% of men and 55.1% of whites. HF etiologies were predominantly ischemic (31.5%), idiopathic (23.6%) and hypertensive (15.7%). The genetic profile was distributed as follows: 122 Ser-Ser (68.5%), 52 Ser-Gly (28.7%) and 5 Gly-Gly (2.8%). There was a significant association between these genotypes and mean NYHA functional class at the end of follow-up (p = 0.014) with Gly-Gly being associated with less advanced NYHA. In relation to the clinical outcomes, there was a significant association (p = 0.026) between mortality and GPRß1-Ser49Gly: the number of deaths in patients with Ser-Gly (12) or Gly-Gly (1) was lower than in those with Ser-Ser (54). The Gly allele had an independent protective effect maintained after multivariate analysis and was associated with a reduction of 63% in the risk of death (p = 0.03; Odds Ratio 0.37 - CI 0.15-0.91). Conclusion The presence of ß1-AR-GP Gly-Gly was associated with better clinical outcome evaluated by NYHA functional class and was a predictor of lower risk of mortality, regardless of other factors, in a 6.7-year of follow-up. (Arq Bras Cardiol. 2020; 114(4):613-615).

Monoaminergic Receptors as Modulators of the Perivascular Sympathetic and Sensory CGRPergic Outflows.

Blood pressure is a highly controlled cardiovascular parameter that normally guarantees an adequate blood supply to all body tissues. This parameter is mainly regulated by peripheral vascular resistance and is maintained by local mediators (i.e., autacoids), and by the nervous and endocrine systems. Regarding the nervous system, blood pressure can be modulated at the central level by regulating the autonomic output. However, at peripheral level, there exists a modulation by activation of prejunctional monoaminergic receptors in autonomic- or sensory-perivascular fibers. These modulatory mechanisms on resistance blood vessels exert an effect on the release of neuroactive substances from the autonomic or sensory fibers that modify blood pressure. Certainly, resistance blood vessels are innervated by perivascular: (i) autonomic sympathetic fibers (producing vasoconstriction mainly by noradrenaline release); and (ii) peptidergic sensory fibers [producing vasodilatation mainly by calcitonin gene-related peptide (CGRP) release]. In the last years, by using pithed rats, several monoaminergic mechanisms for controlling both the sympathetic and sensory perivascular outflows have been elucidated. Additionally, several studies have shown the functions of many monoaminergic auto-receptors and hetero-receptors expressed on perivascular fibers that modulate neurotransmitter release. On this basis, the present review: (i) summarizes the modulation of the peripheral vascular tone by adrenergic, serotoninergic, dopaminergic, and histaminergic receptors on perivascular autonomic (sympathetic) and sensory fibers, and (ii) highlights that these monoaminergic receptors are potential therapeutic targets for the development of novel medications to treat cardiovascular diseases (with some of them explored in clinical trials or already in clinical use).

O Polimorfismo Genético do Receptor Beta-Adrenérgico Tipo 1 Ser49Gly é Preditor de Morte em Pacientes Brasileiros com Insuficiência Cardíaca / Ser49Gly Beta1-Adrenergic Receptor Genetic Polymorphism as a Death Predictor in Brazilian Patients with Heart Failure

Resumo Fundamento O papel do polimorfismo genético do receptor beta1-adrenérgico Ser49Gly (PG-Rβ1-Ser49Gly) como preditor de eventos na insuficiência cardíaca (IC) não está definido para a população brasileira. Objetivos Avaliar a relação entre PG-Rβ1-Ser49Gly e desfechos clínicos em indivíduos com IC com fração de ejeção reduzida. Métodos Análise secundária de prontuários de 178 pacientes e identificação das variantes do PG-Rβ1-Ser49Gly, classificadas como Ser-Ser, Ser-Gly e Gly-Gly. Avaliar sua relação com evolução clínica. Foi adotado nível de significância de 5%. Resultados As médias da coorte foram: seguimento clínico, 6,7 anos; idade, 64,4 anos; 63,5% de homens e 55,1% brancos. A etiologia da IC foi predominantemente isquêmica (31,5%), idiopática (23,6%) e hipertensiva (15,7%). O perfil genético teve a seguinte distribuição: 122 Ser-Ser (68,5%), 52 Ser-Gly (28,7%), e 5 Gly-Gly (2,8%). Houve relação significativa entre esses genótipos e a classe funcional da New York Heart Association (NYHA) ao final do acompanhamento (p = 0,014) com o Gly-Gly associado a NYHA menos avançada. Com relação aos desfechos clínicos, houve associação significativa (p = 0,026) entre mortalidade e PG-Rβ1-Ser49Gly: o número de óbitos em pacientes com Ser-Gly (12) ou Gly-Gly (1) foi menor que com Ser-Ser (54). O alelo Gly teve um efeito protetor independente mantido após análise multivariada e foi associado à redução na chance de óbito de 63% (p = 0,03; odds ratio 0,37 - IC 0,15 a 0,91). Conclusão A presença do PG-Rβ1 Gly-Gly associou-se a melhor evolução clínica avaliada pela classe funcional da NYHA e foi preditor de menor risco de mortalidade, independentemente de outros fatores, em seguimento de 6,7 anos. (Arq Bras Cardiol. 2020; 114(4):616-624)

Abstract Background The role of Ser49Gly beta1-adrenergic receptor genetic polymorphism (ADBR1-GP-Ser49Gly) as a predictor of death in heart failure (HF) is not established for the Brazilian population. Objectives To evaluate the association between ADBR1-GP-Ser49Gly and clinical outcomes in individuals with HF with reduced ejection fraction. Methods Secondary analysis of medical records of 178 patients and genotypes of GPRβ1-Ser49Gly variants, classified as Ser-Ser, Ser-Gly and Gly-Gly. To evaluate their association with clinical outcome. A significance level of 5% was adopted. Results Cohort means were: clinical follow-up 6.7 years, age 63.5 years, 64.6% of men and 55.1% of whites. HF etiologies were predominantly ischemic (31.5%), idiopathic (23.6%) and hypertensive (15.7%). The genetic profile was distributed as follows: 122 Ser-Ser (68.5%), 52 Ser-Gly (28.7%) and 5 Gly-Gly (2.8%). There was a significant association between these genotypes and mean NYHA functional class at the end of follow-up (p = 0.014) with Gly-Gly being associated with less advanced NYHA. In relation to the clinical outcomes, there was a significant association (p = 0.026) between mortality and GPRβ1-Ser49Gly: the number of deaths in patients with Ser-Gly (12) or Gly-Gly (1) was lower than in those with Ser-Ser (54). The Gly allele had an independent protective effect maintained after multivariate analysis and was associated with a reduction of 63% in the risk of death (p = 0.03; Odds Ratio 0.37 - CI 0.15-0.91). Conclusion The presence of β1-AR-GP Gly-Gly was associated with better clinical outcome evaluated by NYHA functional class and was a predictor of lower risk of mortality, regardless of other factors, in a 6.7-year of follow-up. (Arq Bras Cardiol. 2020; 114(4):613-615)