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BioRxiv : the Preprint Server For... Jun 2024Our previous studies have indicated that insulin resistance, hyperglycemia, and hypertension in aged wild-type (WT) mice can be reversed in mice lacking chromogranin-A...
Our previous studies have indicated that insulin resistance, hyperglycemia, and hypertension in aged wild-type (WT) mice can be reversed in mice lacking chromogranin-A (CgA-KO mice). These health conditions are associated with a higher risk of Alzheimer's disease (AD). CgA, a neuroendocrine secretory protein has been detected in protein aggregates in the brains of AD patients. Here, we determined the role of CgA in tauopathies, including AD (secondary tauopathy) and corticobasal degeneration (CBD, primary tauopathy). We found elevated levels of CgA in both AD and CBD brains, which were positively correlated with increased phosphorylated tau in the frontal cortex. Furthermore, CgA ablation in a human P301S tau (hTau) transgenic mice (CgA-KO/hTau) exhibited reduced tau aggregation, resistance to tau spreading, and an extended lifespan, coupled with improved cognitive function. Transcriptomic analysis of mice cortices highlighted altered levels of alpha-adrenergic receptors (Adra) in hTau mice compared to WT mice, akin to AD patients. Since CgA regulates the release of the Adra ligands epinephrine (EPI) and norepinephrine (NE), we determined their levels and found elevated EPI levels in the cortices of hTau mice, AD and CBD patients. CgA-KO/hTau mice exhibited reversal of EPI levels in the cortex and the expression of several affected genes, including Adra1 and 2, nearly returning them to WT levels. Treatment of hippocampal slice cultures with EPI or an Adra1 agonist intensified, while an Adra1 antagonist inhibited, tau hyperphosphorylation and aggregation. These findings reveal a critical role of CgA in regulation of tau pathogenesis via the EPI-Adra signaling axis.
PubMed: 38915622
DOI: 10.1101/2024.06.11.598548 -
Allergy, Asthma & Immunology Research May 2024Concerns regarding the safety of beta-2 agonists have led to revisions of the major asthma guidelines to better address these issues. Although these updates allow for a... (Review)
Review
Concerns regarding the safety of beta-2 agonists have led to revisions of the major asthma guidelines to better address these issues. Although these updates allow for a combination of previous and current strategies, they may confuse clinical practitioners. Beta-2 agonists are vital for alleviating asthma symptoms by relaxing smooth muscles; however, they also pose significant risks by inducing pro-inflammatory mediators both and . In addition to the risks of overuse and symptom masking, the use of beta-agonists alone at therapeutic doses can worsen airway inflammation and enhance virus-induced inflammation during asthma exacerbation. Inhaled corticosteroids (ICS) can effectively prevent these adverse effects. With new insights into the mechanisms of these adverse events, reserving short-acting beta-agonists for acute symptom relief during exacerbations and only for those who are already on ICS or oral steroids represents a careful approach to using beta-agonists with least adverse effects in patients with asthma. However, a major drawback of this approach is the potential non-compliance with ICS, leading to beta-agonist use without the necessary counteraction by ICS. An optimal strategy, both during and outside exacerbations, would integrate beta-agonists into an anti-inflammatory regimen that includes ICS, ideally combined with the same inhaler to ensure their concurrent use where finances allow. This would maintain the beneficial effects of beta-agonists, such as bronchodilation, while preventing the adverse effects from the induction of inflammatory mediators. This method is aligned with diverse clinical settings, maximizes the safe use of beta-agonists, and supports a comprehensive guideline-compliant management strategy.
PubMed: 38910281
DOI: 10.4168/aair.2024.16.3.217 -
Biological & Pharmaceutical Bulletin 2024Guanfacine, used as a medication for attention-deficit/hyperactivity disorder (ADHD), leads to a high incidence of somnolence, in contrast to methylphenidate, which...
Guanfacine, used as a medication for attention-deficit/hyperactivity disorder (ADHD), leads to a high incidence of somnolence, in contrast to methylphenidate, which leads to a high incidence of insomnia. The impact of somnolence on continuing guanfacine treatment is unclear. Therefore, we investigated the reasons for discontinuing guanfacine and analyzed the factors associated with discontinuation caused by somnolence. We surveyed 96 patients under guanfacine from July 2017 to December 2021 at the Saga University Hospital. Patients who discontinued guanfacine by the end date of our study were divided into a median early and late group. We compared the reasons for discontinuation in both groups. Of all patients, 47 continued and 49 discontinued guanfacine. A higher percentage of patients discontinued guanfacine caused by somnolence for ≤70 d than for >70 d of treatment (44.0 vs. 8.3%; p = 0.008). When stratified by the concomitant use of other ADHD drugs, somnolence resulted in a higher discontinuation rate for ≤70 d than for >70 d of treatment without concomitant use (55.0 vs. 7.1%; p = 0.009). Nonetheless, concomitant use resulted in no difference. In conclusion, somnolence affects the early discontinuation of guanfacine as an ADHD drug. The combination of methylphenidate or atomoxetine may decrease withdrawal caused by somnolence.
Topics: Guanfacine; Humans; Attention Deficit Disorder with Hyperactivity; Male; Female; Child; Adolescent; Sleepiness; Adrenergic alpha-2 Receptor Agonists; Methylphenidate
PubMed: 38910124
DOI: 10.1248/bpb.b24-00147 -
Indian Journal of Anaesthesia Jun 2024Electroconvulsive therapy (ECT) is an effective intervention for psychiatric patients. Succinylcholine is considered the drug of choice for muscle relaxation for ECT....
BACKGROUND AND AIM
Electroconvulsive therapy (ECT) is an effective intervention for psychiatric patients. Succinylcholine is considered the drug of choice for muscle relaxation for ECT. Significant adverse effects of succinylcholine include fasciculation and myalgia. Dexmedetomidine is a highly selective α-2 adrenergic agonist. This study aims to determine the efficacy of a low dose of dexmedetomidine in reducing succinylcholine-induced myalgia in patients receiving ECT.
METHODS
This randomised controlled trial was conducted on 100 patients, aged 18-65 years, undergoing ECT, who were randomly allocated into two groups with an allocation ratio of 1:1. Group D received intravenous (IV) dexmedetomidine 0.25 µg/kg, and Group C received IV normal saline (0.9%). Patients' self-reported myalgia scores were measured after 60 min of the procedure. Fasciculations were noted after IV succinylcholine administration. Heart rate (HR) and mean blood pressure (MBP) were measured at baseline, after infusion (5 min) and after ECT (0, 2.5, 5, 10, 15, 30 min). Continuous data were analysed using a Student's -test for two-group comparisons, a mixed model analysis of variance for group comparisons and various time point analyses. Categorical data were analysed using the Chi-square/Fisher's exact test.
RESULTS
There were no differences between the groups regarding demographics. Myalgia and fasciculations were less in Group D than in Group C ( < 0.001). MBP and HR changes were comparable ( > 0.05).
CONCLUSION
A low dose of dexmedetomidine (0.25 µg/kg) effectively reduces myalgia and fasciculations due to succinylcholine in patients undergoing electroconvulsive therapy.
PubMed: 38903251
DOI: 10.4103/ija.ija_1159_23 -
Circulation Research Jun 2024GPCRs (G protein-coupled receptors), also known as 7 transmembrane domain receptors, are the largest receptor family in the human genome, with ≈800 members. GPCRs... (Review)
Review
GPCRs (G protein-coupled receptors), also known as 7 transmembrane domain receptors, are the largest receptor family in the human genome, with ≈800 members. GPCRs regulate nearly every aspect of human physiology and disease, thus serving as important drug targets in cardiovascular disease. Sharing a conserved structure comprised of 7 transmembrane α-helices, GPCRs couple to heterotrimeric G-proteins, GPCR kinases, and β-arrestins, promoting downstream signaling through second messengers and other intracellular signaling pathways. GPCR drug development has led to important cardiovascular therapies, such as antagonists of β-adrenergic and angiotensin II receptors for heart failure and hypertension, and agonists of the glucagon-like peptide-1 receptor for reducing adverse cardiovascular events and other emerging indications. There continues to be a major interest in GPCR drug development in cardiovascular and cardiometabolic disease, driven by advances in GPCR mechanistic studies and structure-based drug design. This review recounts the rich history of GPCR research, including the current state of clinically used GPCR drugs, and highlights newly discovered aspects of GPCR biology and promising directions for future investigation. As additional mechanisms for regulating GPCR signaling are uncovered, new strategies for targeting these ubiquitous receptors hold tremendous promise for the field of cardiovascular medicine.
Topics: Humans; Receptors, G-Protein-Coupled; Animals; Cardiovascular Diseases; Signal Transduction; Drug Discovery; History, 21st Century; History, 20th Century
PubMed: 38900852
DOI: 10.1161/CIRCRESAHA.124.323067 -
PPAR Research 2024Partial and full PPAR- agonists have shown promising effects and antihypertensive and antidiabetic agents through increased plasma adiponectin concentration. This study...
Partial and full PPAR- agonists have shown promising effects and antihypertensive and antidiabetic agents through increased plasma adiponectin concentration. This study is aimed at examining the role of PPAR-, alpha-adrenoceptors, and adiponectin receptors in the modulation of vasopressor responses to angiotensin II (Ang II) and adrenergic agonists, after a subset treatment of partial and full PPAR- agonists, each individually, and also when coupled with adiponectin in SHRs. The antioxidant potential and metabolic indices for these animals were also determined. Group I (WKY) and group II (SHR) were designated as normotensive control and hypertensive control, respectively. Groups III (SHR) and IV (SHR) received irbesartan (30 mg/kg) and pioglitazone (10 mg/kg) orally for 28 days, and groups V (SHR), VI (SHR), and VII (SHR) were treated with adiponectin (2.5 g/kg) intraperitoneally alone, in combination with irbesartan, and in combination with pioglitazone, respectively, from days 21 to 28 only. On day 29, sodium pentobarbitone (60 mg/kg) was used to anesthetize all test animals, and systemic hemodynamic and plasma adiponectin concentrations and and antioxidant potential were measured. As compared to the WKY control, the SHR control group's noninvasive blood pressure and basal mean arterial pressure were significantly greater, along with increased arterial stiffness, lower plasma nitric oxide, adiponectin concentration, and antioxidant enzyme levels (all < 0.05). However, they were gradually normalized by single drug treatments in all groups, and to a greater extent in the SHR + Irb + Adp group ( < 0.05). In the acute study, the dose dependant mean arterial pressure responses to intravenously administered adrenergic agonists and angiotensin-II were significantly larger in SHRs as compared to WKY by 20-25%. Adiponectin alone and in combination significantly blunted vasopressor responses to these alpha-adrenergic agonists in the SHR + Pio + Adp group by 63%, whereas attenuated responses to ANG-II administration to 70% in SHR + Irb + Adp. In conclusion, the combined treatment of adiponectin with PPAR-agonists reduced the systemic vascular responses to adrenergic agonists and improved arterial stiffness. This an evidence of the interaction of adiponectin receptors, PPAR-, alpha-adrenoceptors, and ANG-II in the systemic vasculature of SHRs. A significant level of synergism has also been proved among full PPAR- agonists and adiponectin receptors.
PubMed: 38899161
DOI: 10.1155/2024/5868010 -
Nutrients May 2024Pre-workout supplements are popular among sport athletes and overweight individuals. Phenethylamines (PEAs) and alkylamines (AA) are widely present in these supplements....
Pre-workout supplements are popular among sport athletes and overweight individuals. Phenethylamines (PEAs) and alkylamines (AA) are widely present in these supplements. Although the health effects of these analogues are not well understood yet, they are hypothesised to be agonists of adrenergic (ADR) and trace amine-associated receptors (TAARs). Therefore, we aimed to pharmacologically characterise these compounds by investigating their activating properties of ADRs and TAAR1 . The potency and efficacy of the selected PEAs and AAs was studied by using cell lines overexpressing human ADRα/α/α/α/α/β/β or TAAR1. Concentration-response relationships are expressed as percentages of the maximal signal obtained by the full ADR agonist adrenaline or the full TAAR1 agonist phenethylamine. Multiple PEAs activated ADRs (EC = 34 nM-690 µM; E = 8-105%). Almost all PEAs activated TAAR1 (EC = 1.8-92 µM; E = 40-104%). Our results reveal the pharmacological profile of PEAs and AAs that are often used in food supplements. Several PEAs have strong agonistic properties on multiple receptors and resemble potencies of the endogenous ligands, indicating that they might further stimulate the already activated sympathetic nervous system in exercising athletes via multiple mechanisms. The use of supplements containing one, or a combination of, PEA(s) may pose a health risk for their consumers.
Topics: Phenethylamines; Humans; Receptors, G-Protein-Coupled; Dietary Supplements; Receptors, Adrenergic; HEK293 Cells
PubMed: 38892500
DOI: 10.3390/nu16111567 -
International Journal of Molecular... May 2024The N-terminal portion of the octapeptide angiotensin II (DRVYIHPF; AngII), a vasopressor peptide that favorably binds to, and activates, AngII type 1 receptor (ATR),... (Review)
Review
Structural Features Influencing the Bioactive Conformation of Angiotensin II and Angiotensin A: Relationship between Receptor Desensitization, Addiction, and the Blood-Brain Barrier.
The N-terminal portion of the octapeptide angiotensin II (DRVYIHPF; AngII), a vasopressor peptide that favorably binds to, and activates, AngII type 1 receptor (ATR), has an important role in maintaining bioactive conformation. It involves all three charged groups, namely (i) the N-terminal amino group cation, (ii) the Asp sidechain anion and (iii) the Arg guanidino cation. Neutralization of any one of these three charged groups results in a substantial reduction (<5%) in bioactivity, implicating a specialized function for this cluster. In contrast, angiotensin A (ARVYIHPF; AngA) has reduced bioactivity at ATR; however, replacement of Asp in AngII with sarcosine (N-methyl-glycine) not only restores bioactivity but increases the activity of agonist, antagonist, and inverse agonist analogues. A bend produced at the N-terminus by the introduction of the secondary amino acid sarcosine is thought to realign the functional groups that chaperone the C-terminal portion of AngII, allowing transfer of the negative charge originating at the C-terminus to be transferred to the Tyr hydroxyl-forming tyrosinate anion, which is required to activate the receptor and desensitizes the receptor (tachyphylaxis). Peptide (sarilesin) and nonpeptide (sartans) moieties, which are long-acting inverse agonists, appear to desensitize the receptor by a mechanism analogous to tachyphylaxis. Sartans/bisartans were found to bind to alpha adrenergic receptors resulting in structure-dependent desensitization or resensitization. These considerations have provided information on the mechanisms of receptor desensitization/tolerance and insights into possible avenues for treating addiction. In this regard sartans, which appear to cross the blood-brain barrier more readily than bisartans, are the preferred drug candidates.
Topics: Blood-Brain Barrier; Angiotensin II; Humans; Animals; Receptor, Angiotensin, Type 1; Protein Conformation
PubMed: 38891966
DOI: 10.3390/ijms25115779 -
Therapeutic Advances in Respiratory... 2024Some systematic reviews (SRs) on triple therapy (consisting of long-acting β-agonist, long-acting muscarinic antagonist, and inhaled corticosteroid, LABA/LAMA/ICS) for...
BACKGROUND
Some systematic reviews (SRs) on triple therapy (consisting of long-acting β-agonist, long-acting muscarinic antagonist, and inhaled corticosteroid, LABA/LAMA/ICS) for chronic obstructive pulmonary disease (COPD) have reported conflicting results. As the number of syntheses increases, the task of identifying and interpreting evidence becomes increasingly complex and demanding.
OBJECTIVES
To provide a comprehensive overview of the efficacy and safety of triple therapy for COPD.
DESIGN
Overview of SRs.
METHODS
Two independent reviewers conducted comprehensive searches in PubMed, Embase, Web of Science, and the Cochrane Library to identify relevant SRs that compared triple therapy with any non-triple therapy for COPD, from the inception of these databases until 1 June 2023. The AMSTAR 2 and GRADE tools were utilized to assess the quality of the included studies and the evidence for each outcome.
RESULTS
Eighteen SRs encompassing 30 original studies and involving 47,340 participants were analyzed. The overall AMSTAR 2 rating revealed that 3 SRs were of low quality, 13 SRs were of critically low quality, and 2 SRs were of high quality. No high-certainty evidence revealed a significant advantage of triple therapy in improving lung function or reducing acute exacerbations. However, all evidence, including one high certainty, supported the benefits of improving quality of life. Regarding all-cause mortality, no significant difference was found when compared to LAMA or ICS/LABA; however, high-certainty evidence confirmed its effectiveness when compared with LABA/LAMA. Notably, high-certainty evidence indicated that triple therapy was associated with a significant increase in the risk of pneumonia compared to LABA/LAMA.
CONCLUSION
Triple therapy demonstrated notable benefits in improving lung function, reducing exacerbations, improving quality of life, and reducing all-cause mortality. However, it is important to note that it may also significantly increase the risk of pneumonia.
TRIAL REGISTRATION
This overview protocol was prospectively registered with PROSPERO (No. CRD42023431548).
Topics: Humans; Pulmonary Disease, Chronic Obstructive; Systematic Reviews as Topic; Drug Therapy, Combination; Muscarinic Antagonists; Treatment Outcome; Administration, Inhalation; Adrenergic beta-2 Receptor Agonists; Adrenal Cortex Hormones; Bronchodilator Agents; Lung; Quality of Life
PubMed: 38877687
DOI: 10.1177/17534666241259634 -
Autonomic Neuroscience : Basic &... Jun 2024Urinary bladder dysfunction might be related to disturbances at different levels of the micturition reflex arc. The current study aimed to further develop and evaluate a...
Urinary bladder dysfunction might be related to disturbances at different levels of the micturition reflex arc. The current study aimed to further develop and evaluate a split bladder model for detecting and analysing relaxatory signalling in the rat urinary bladder. The model allows for discrimination between effects at the efferent and the afferent side of the innervation. In in vivo experiments, the stimulation at a low frequency (1 Hz) of the ipsilateral pelvic nerve tended to evoke relaxation of the split bladder half (contralateral side; -1.0 ± 0.4 mN; n = 5), in contrast to high frequency-evoked contractions. In preparations in which the contralateral pelvic nerve was cut the relaxation occurred at a wider range of frequencies (0.5-2 Hz). In separate experiments, responses to 1 and 2 Hz were studied before and after intravenous injections of propranolol (1 mg/kg IV). The presence of propranolol significantly shifted the relaxations into contractions. Also, electrical stimulation of the ipsilateral pudendal nerve evoked relaxations of similar magnitude as for the pelvic stimulations, which were also affected by propranolol. In control in vitro experiments, substances with β-adrenoceptor agonism, in contrast to a selective α-agonist, evoked relaxations. The current study shows that the split bladder model can be used for in vivo studies of relaxations. In the model, reflex-evoked sympathetic responses caused relaxations at low intensity stimulation. The involvement of β-adrenoceptors is supported by the sensitivity to propranolol and by the in vitro observations.
PubMed: 38875740
DOI: 10.1016/j.autneu.2024.103194