Search Results (121)

Background: Melanoma incidence is rising rapidly worldwide and stands out due to its high lethality. Despite advances in clinical treatment and in understanding melanoma-sensitive genes and molecular pathogenesis, a specific area of ongoing research is the connection between stress-related β-adrenergic receptors (ARs), hypoxia, and neovascularization in melanoma tumor progression. This exploratory study aimed to investigate the expression of β3-AR, HIF-1α, and CD31 in several cellular subsets of atypical melanocytic lesions and their interplay in promoting melanoma malignancy. Methods: Twenty-seven patients with melanocytic lesions at different stages that were surgically removed were retrospectively selected; clinical-pathological and dermoscopic data were collected. Results: Immunohistochemical and digital evaluation revealed a significant upregulation of β3-AR in malignant melanoma melanocytes and in macrophages from invasive >pT1a melanomas compared to dysplastic nevi. Increased HIF-1α expression in malignant melanocytes and CD31 expression levels in >pT1a melanomas were observed. Ulcerated lesions exhibited a higher percentage of β3-AR, HIF-1α, and CD31 expression. Pearson correlation analysis revealed positive associations among these markers in human malignant melanoma, suggesting a potential relationship between adrenergic signaling, hypoxia, and tumor vascularization. Conclusions: These exploratory findings suggest that β3-AR, HIF-1α, and CD31 may represent interconnected components of the melanoma microenvironment. Unraveling these interactions in larger, independent cohorts and functional studies may provide additional insights into melanoma biology and help define their potential translational relevance. Full article

Excessive administration of epinephrine and norepinephrine in critically ill patients may trigger a catecholamine storm and contribute to acute kidney injury (AKI) through activation of β-adrenoceptor signaling. Although clinical observations link high-dose catecholamine exposure to increased AKI risk, experimental models and mechanistic studies remain limited. We established a rodent model of combined epinephrine and norepinephrine infusion to investigate the renoprotective effects of subtype-selective β-adrenoceptor blockers. Animals received the β1-selective blockers metoprolol or atenolol, or the β2-selective blocker ICI 118,551. β1-adrenoceptor blockade, particularly with metoprolol, significantly attenuated renal histopathological injury and improved biochemical markers of kidney dysfunction. These protective effects were associated with suppression of ferroptosis-related pathways in the renal cortex. Atenolol partially improved biochemical parameters but did not significantly reduce tubulointerstitial damage, whereas β2-adrenoceptor blockade conferred limited functional benefit despite modest morphological improvement. Collectively, our findings indicate that β1-adrenoceptor activation plays a critical role in catecholamine-induced AKI by promoting ferroptosis. Targeting β1-adrenoceptors, especially with metoprolol, may represent a potential therapeutic strategy for preventing renal injury during catecholamine storms. Full article

Hydrolyzed collagen (HC) derived from salmon skin is a promising source of bioactive peptides. In this study, the vasorelaxant effects and potential mechanisms of action of HC on isolated rat thoracic aorta rings were investigated using the organ bath technique. The vasorelaxant properties of HC were evaluated using aortic rings from Wistar rats pre-contracted with phenylephrine (PE) or potassium chloride (KCl). HC induced significant vasorelaxation in both endothelium-intact and endothelium-denuded rings, indicating that its mechanism of action was independent of the endothelium and involved direct effects on vascular smooth muscle cells. The vasorelaxant effect of HC was reduced when pre-contraction was induced by tetraethylammonium chloride (TEA). However, the vasodilatory effects of HC were not significantly inhibited by all K⁺ channel blockers, including glibenclamide, barium chloride (BaCl₂), or 4-aminopyridine (4-AP). Additionally, pre-incubation with prazosin, an α-adrenoceptor blocker, significantly reduced the vasorelaxation induced by HC, whereas propranolol, a β-adrenoceptor blocker, had no effect. In addition, HC inhibited CaCl₂-induced contractions induced by both PE and caffeine in a Ca²⁺-free solution. Therefore, HC exhibited the vasorelaxant effects through an endothelium-independent mechanism. The vasodilatory effects of HC were associated with the activation of K_Ca channels, suppression of PE-induced contraction via α₁-adrenergic receptor pathways, and inhibition of CaCl₂-induced contractions by modulating intracellular Ca²⁺ release and extracellular Ca²⁺ influx in vascular cells. Full article

Cardiac fibrosis is a hallmark of cardiac aging and a major contributor to development of heart failure. However, therapeutic strategies that specifically target cardiac fibrosis remain limited. In this study, we demonstrate that small-molecule compound ML216 exerts protective effects against aging-associated or β-adrenoceptor agonist isoproterenol-induced cardiac fibrosis in vitro or in vivo. Mechanistically, ML216 inhibits transforming growth factor-β1 (TGF-β1) signaling by reducing TGF-β1 protein levels, thereby attenuating Mothers against decapentaplegic homolog (SMAD) phosphorylation and downstream induction of connective tissue growth factor (CTGF). This leads to a marked suppression of fibrotic genes Col1a1, Cnn2, and Acta2, ultimately resulting in reduced fibrosis. Additionally, the inhibition of the TGF-β1 pathway alleviates cardiomyocytes apoptosis, which may further limit inflammatory responses and contributes to the overall attenuation of cardiac fibrosis. Collectively, these findings demonstrate that ML216 mitigates cardiac fibrosis through the inhibition of TGF-β1 pathway-mediated fibrotic signaling and apoptosis, highlighting its potential as a therapeutic candidate for the treatment of cardiac fibrosis. Full article

Dihydroquercetin (DHQ) is a promising object for the development of a treatment for patients with obesity and prediabetes requiring a moderate therapeutic effect. This paper reports a clinical case of DHQ application in a 30-year-old Caucasian male and proposes a molecular mechanism of its anti-obesity effect. DHQ was administrated as a dietary supplement at a dose of 100–200 mg/day during 3 months with treatment interruption for 1 month. The data collected one month before the treatment were used as a control. The molecular aspects were studied via molecular docking with β₃-adrenoceptor (ADRB3, PDB ID: 9IJE) and peroxisome proliferator-activated receptor γ (PPARG, PDB ID: 2ZNO) and molecular dynamic simulation under conditions mimicking a human cellular environment. A pronounced weight decrease up to 0.73 kg/week was observed during DHQ administration. The highest affinity to ADRB3 was observed for the non-ionized H2aH3e-conformation of 2S,3R-DHQ (–8.846 kcal/mol). Molecules with 2S-configuration demonstrate 0.332 kcal/mol higher affinity to PPARG compared to 2R-stereoisomers. The intermolecular complex with cis-DHQ demonstrated higher stability in molecular dynamics simulation. The insights gained from this study may contribute to our understanding of flavonoids not merely as antioxidants but also as active ingredients that selectively interact with receptors. If future investigations confirm these results, they may serve as a foundation for developing a new class of anti-obesity remedies that act via ADRB3. Full article

Older adults with multiple diseases are likely to be prescribed multiple medications including anticholinergic agents, which are frequently prescribed to manage conditions such as overactive bladder and chronic obstructive pulmonary disease and Parkinson’s disease. Overactive bladder (OAB) has been the subject of increased disease awareness and is a common and significant cause of reduced quality of life, particularly in the elderly. The selective β₃ adrenoceptor agonist, mirabegron was developed for the pharmacological treatment of OAB. Mirabegron has been shown to exert off-target effects on various functional proteins such as muscarinic receptors in rat tissues. This agent may relax the detrusor muscle by activating β₃ adrenoceptors and also antagonizing muscarinic receptors. Mirabegron and antimuscarinics exerted additive effects on muscarinic receptor binding and relaxant responses of cholinergic contractions of the detrusor muscle. Mirabegron excreted in human urine appears to directly attenuate muscarinic receptor-mediated functions in the bladder. Combination therapy of mirabegron and solifenacin in patients with OAB may enhance not only their therapeutic effects on OAB, but also increase the risk of anticholinergic adverse effects. Therefore, the safety of concomitant use of mirabegron and other drugs such as antimuscarinics for elderly patients needs to be carefully considered. Full article

Extensive research in laboratory rodents has shown that novelty exposure enhances the consolidation of memories for preceding or following low-arousal events by elevating dopamine release in the dorsal hippocampus (dHipp). Additionally, numerous studies have demonstrated that post-encoding noradrenergic activation of the basolateral amygdala (BLA) can also enhance memory consolidation in dHipp. Since the BLA is most active during emotionally arousing or stress-related situations, it was suggested that this nuclear complex mediates the effects of emotional salience on memory consolidation. However, it is presently unknown whether the reinforcement of memory storage in dHipp induced by novel and arousing environmental conditions results from the interaction between these two modulatory systems. To test the hypothesis of a functional interaction between dopaminergic and noradrenergic systems, this study assessed their combined effects on a low-arousal object-location (OL) task. Rats received post-training intra-BLA infusions of vehicle or clenbuterol (Clen), a selective β-adrenoceptor agonist. Novelty-induced dopamine release in the dHipp was enhanced by omitting habituation prior to training, and the contribution of dopamine signaling was further evaluated using pre-infusion administration of the D1/D5 receptor antagonist SCH 23390. The distribution of two important proteins for memory processing, namely the activity-regulated cytoskeleton-associated protein (Arc) and the phosphorylated form of the transcription factor, cAMP-response element-binding protein (pCREB) in the dHipp, was explored in a subset of rats perfused 60 min after the training phase. Stimulation of the BLA significantly increased the number of Arc- and pCREB-positive cells in several dHipp areas. The preceding application of SCH 23390, however, substantially decreased these effects in the same areas, i.e., the dentate gyrus (DG), CA2, and CA1 subregions for pCREB, and the CA3b, CA3c, CA2, and CA1 subregions for Arc. This interaction is considered essential for the initial stages of memory consolidation. The obtained results indicate the presence of a region-specific interaction between BLA modulatory inputs and intrahippocampal dopaminergic transmission, the mechanisms of which remain to be elucidated. Full article

Obesity has reached epidemic proportions, driven by energy imbalance and limited capacity for adaptive thermogenesis. Brown (BAT) and beige adipose tissues dissipate energy through non-shivering thermogenesis (NST), primarily via uncoupling protein-1 (UCP1), making them attractive targets for increasing energy expenditure (EE). The canonical β-adrenergic pathway robustly activates NST in rodents through β3 adrenoceptors; however, translational success in humans has been limited by low β3 expression, off-target cardiovascular effects, and the emerging dominance of β2-mediated signaling in human BAT. Consequently, attention has shifted to non-adrenergic and UCP1-independent mechanisms that offer greater tissue distribution and improved safety profiles. This review examines a broad spectrum of alternative receptors and pathways—including GPRs, TRP channels, TGR5, GLP-1R, thyroid hormone receptors, estrogen receptors, growth hormone, BMPs, sirtuins, PPARs, and interleukin signaling—as well as futile substrate cycles (Ca²⁺, creatine, and glycerol-3-phosphate) that sustain thermogenesis in beige adipocytes and skeletal muscle. Pharmacological agents (natural compounds, peptides, and small molecules) and non-pharmacological interventions (cold exposure, exercise, diet, and time shift) targeting these pathways are critically evaluated. We highlight the translational gaps between rodent and human studies, the promise of multimodal therapies combining low-dose adrenergic agents with non-adrenergic activators, and emerging strategies such as sarco/endoplasmic reticulum calcium ATPase protein (SERCA) modulators and tissue-specific delivery. Ultimately, integrating adrenergic and non-adrenergic approaches holds the greatest potential for safe, effective, and sustainable obesity management. Full article

Glucagon is an endogenous peptide that is produced in the pancreas. Via glucagon receptors, glucagon increases the beating rate in cultured rat neonatal cardiomyocytes and also in isolated right atrial preparations from adult rats. Moreover, in living adult mice, injections of glucagon can elevate the heart rate. It is unknown whether these effects of glucagon in living adult mice are mediated via central glucagon receptors or via a direct effect on cardiac glucagon receptors. Thus, we tested the hypothesis that glucagon can exert a direct positive chronotropic effect in the adult mouse heart. We measured the contractile effects of cumulatively increasing concentrations of glucagon (0.1–100 nM) in isolated paced (1 Hz) left atrial preparations, in isolated spontaneously beating right atrial preparations and in isolated spontaneously beating retrogradely perfused whole hearts. We detected in isolated right atrial preparations time- and concentration-dependent positive chronotropic effects of glucagon that were reversed by the glucagon receptor antagonists SC203972 and desglucagon. The positive chronotropic effects of glucagon were also attenuated by 1 µM of ivabradine, an inhibitor of the hyperpolarization-activated cation channels (HCN), but not by 100 nM rolipram, a phosphodiesterase 4 inhibitor, nor by 10 µM of propranolol, a β-adrenoceptor antagonist. Moreover, the positive chronotropic effects of glucagon were also attenuated by stimulation of the A₁-adenosine receptor or muscarinic receptors. Glucagon decreased the force of contraction in right atrial preparations. In left atrial preparations, glucagon failed to alter the force of contraction. In isolated adult mouse hearts perfused in the Langendorff mode, 10 nM of glucagon increased the beating rate and reduced left ventricular force of contraction. The gene expression of the glucagon receptors was lowest in the left atrium, higher in the ventricle and highest in the right atrium of adult mice. In summary, glucagon exerted a positive chronotropic effect in the mouse heart via glucagon receptors, mediated, at least in part, via HCN channels in the sinus node. Full article

Depression is a multifactorial disorder shaped by genetic, psychosocial, and biological influences, with hypotheses ranging from monoamine deficiency and neuroplasticity deficits to inflammation and stress-induced dysregulation. St. John’s wort (Hypericum perforatum L.) has long been used as an herbal antidepressant and is supported by clinical evidence for efficacy and safety in mild-to-moderate depression. While its multimodal mechanisms have been linked to neurotransmitter reuptake inhibition, neuroendocrine regulation, and modulation of neuroplasticity, recent findings suggest an additional role at the membrane level. Emerging lipidomic studies highlight that Ze 117, a low-hyperforin H. perforatum extract, counteracts stress- and glucocorticoid-induced increases in membrane fluidity by modulating lipid composition and cholesterol metabolism. These effects normalize receptor mobility and signal transduction, particularly of β1-adrenoceptors, and modulate glycerophospholipid metabolism in both cellular and animal models. Such membrane-stabilizing properties may represent a novel mechanistic pathway complementing classical neurochemical actions. This review revisits the mechanisms of St. John’s wort with a special focus on its impact on membrane lipids, positioning lipidomics as a promising tool for elucidating antidepressant activity. These insights may open avenues toward personalized therapeutic strategies in depression. Full article

Wound healing is impaired under diabetic conditions due to reduced angiogenesis, thereby increasing the risk of wound-healing complications. Studies have shown that inhibition of α- and β-adrenoceptors delays wound healing. This study investigates the effects of topical salbutamol (TS) on STZ-induced diabetic wound healing in rats. The rats were divided into two initial groups: non-diabetic and diabetic. Diabetes mellitus was induced in the second group with STZ (65 mg/kg). Excision wounds were inflicted on the dorsal thoracic region, 1–1.5 cm away from the vertebral column on either side, following anesthesia on all groups. Group 2 was subdivided into untreated diabetic wounds, low-dose-TS-treated diabetic wounds (6.25 mg/mL), medium-dose-TS-treated diabetic wounds (12.5 mg/mL), and high-dose-TS-treated diabetic wounds (25 mg/mL), and were monitored for 14 days. Percentage wound contraction and the time required for complete wound closure were observed and recorded. In addition, oxidative stress and inflammatory markers such as NO, CRP, MPO, TGF-β1, TNF-α, IL-6, IL-1β, NO, and hexosamine were estimated in wound exudates and tissue over 14 days. TS treatment resulted in 100% wound contraction in all treated wounds within 14 days compared to untreated non-diabetic and diabetic wounds. Increased NO, TGF-β1, and hexosamine activity was observed in TS-treated wounds when compared to untreated diabetic wounds. In addition, TS treatment decreased the activity of IL-1β, TNF-α, IL-6, CRP, and MPO, all of which were elevated in the untreated diabetic wounds. The current study shows that the application of TS significantly improved diabetic wound contraction and aided the healing process. Angiogenic markers, such as TGF-β1 and NO, were prominently increased, supporting the role of sympathetic nerve stimulation in angiogenesis. Full article

The antipsychotic drug haloperidol is found on the WHO list of essential drugs. In vitro, haloperidol demonstrates binding affinity for various receptors, including histamine H₂ receptors (H₂Rs). Several cardiac effects of haloperidol are known, but it remains unclear whether H₂Rs are involved. Here, the hypothesis was tested that haloperidol has the potential to act as either an agonist or an antagonist of human cardiac H₂Rs. The contractile effects of haloperidol were studied in isolated left and right atrial preparations from transgenic mice overexpressing human H₂Rs in the heart (H₂-TG), and compared to human atrial preparations from adult patients. Haloperidol reduced the histamine-stimulated force of contraction in the human atrial preparations as well as the histamine-stimulated force of contraction and beating rate in the left and right atrial preparations from the H₂-TG, respectively. Moreover, haloperidol reduced the isoprenaline-stimulated force of contraction in the human atrial preparations. In the wild-type mouse preparations, haloperidol only reduced the isoprenaline-stimulated beating rate in the right atria, but not the force in the left atria. Principally, haloperidol is capable of acting as an antagonist of both H₂Rs and β-adrenoceptors in the human heart. However, the effects are only relevant at very high doses of haloperidol, which are never or seldom achieved in practice. Full article

Metabolic syndrome (MetS) is a worldwide problem affecting at least one-third of the population. MetS patients have increased cardiovascular risk associated with an abnormal β-adrenergic response; however, it is not clear how MetS affects the cardiac β-adrenergic system. We analyzed cardiac function and the β-adrenergic response in an experimental model of MetS in rats by recording pressure–volume (PV) loops via an open-chest approach and performed a biochemical characterization of the cardiac β-adrenergic system through ELISA, radioligand binding assays, and Western blotting. Microscopy was employed to evaluate cardiac hypertrophy, fibrosis, and ultrastructure. MetS rats exhibited cardiac dysfunction, evidenced by a reduced cardiac output and ejection fraction, not explained by heart hypertrophy or fibrosis. MetS rats also had an elevated susceptibility to lethal arrhythmia following intra-cardiac administration of the non-selective β-adrenergic agonist isoproterenol, suggesting alterations in the β-adrenergic system. The total serum adrenaline and noradrenaline levels were higher in the MetS animals than those in the control group. The radioligand binding assays indicated no change in the βAR density; however, the Western blot analyses revealed decreased levels of Gα_s proteins and β-arrestin 1, but increased β₂AR and Gα_i protein levels. This study contributes to our understanding of how MetS can alter cardiac function, raising the risk of lethal arrhythmia induced by the β-adrenergic (fight or flight) response and underscores the relevance of therapeutically targeting MetS before its pathological progression toward cardiomyopathy. Full article

Background and Objectives: This study aimed to assess whether the addition of fractional CO₂ laser therapy to standard pharmacologic treatment with Mirabegron, a β3-adrenoceptor agonist, enhances the clinical outcomes in the management of overactive bladder syndrome (OAB) in postmenopausal women. Materials and Methods: Τhis was a prospective, randomized, double-blind, sham-controlled trial including 50 postmenopausal women with moderate-to-severe OAB symptoms. Participants were randomized (1:1) to receive mirabegron 50 mg daily in combination with either active fractional CO₂ laser therapy (Group A) or sham laser treatment (Group B). Both groups underwent three monthly sessions of vaginal laser treatment and were followed for a total of four months. Clinical assessments were performed at baseline and monthly visits (T0–T3), using validated instruments including the Overactive Bladder Questionnaire (OAB-q), King’s Health Questionnaire (KHQ), Urinary Distress Inventory (UDI-6), Pelvic Floor Impact Questionnaire (PFIQ-7), Patient Global Impression of Improvement (PGI-I), and 3-day voiding diaries. The trial was registered at ClinicalTrials.gov (Identifier: NCT03846895). Results: Significant symptom improvement was observed within both groups over time, with reductions in urinary frequency, urgency, nocturia, and incontinence episodes, as well as improvements in quality-of-life scores. However, intergroup comparisons revealed no statistically significant differences in any primary or secondary outcomes. Both treatment modalities demonstrated similar effectiveness across all measured parameters. Conclusions: In this randomized controlled trial, the adjunctive use of fractional CO₂ laser therapy did not offer additional clinical benefit beyond mirabegron monotherapy in the short-term management of OAB. These findings underscore the need for further investigation into tailored therapeutic strategies, particularly in populations with overlapping genitourinary syndrome of menopause or more refractory OAB symptoms. Full article

It has long been recognised that airway smooth muscle cells (ASMCs) possess an abundance of M2 muscarinic receptors (M2Rs). However, the contribution of postjunctional M2Rs to contractions of airway smooth muscle (ASM) induced by the release of acetylcholine (ACh) from parasympathetic nerves was thought to be minimal. Instead, it was believed that these responses were exclusively mediated by activation of M3Rs. However, evidence is emerging that postjunctional M2Rs may have a greater role than previously realised. In this review, we discuss ACh signalling in airways, highlighting the well-established autoinhibitory role of prejunctional M2Rs and the putative roles of postjunctional M2Rs to cholinergic contractions of ASM. The cellular mechanisms that underpin M2R-dependent contractions of ASM are reviewed, with a particular emphasis on the role of ion channels in these responses. The regulation of M2R signalling pathways by β-adrenoceptor activation is also considered, along with the potential involvement of postjunctional M2Rs in airway diseases such as asthma and chronic obstructive pulmonary disease (COPD). Full article