Role of Dopamine in the Heart in Health and Disease

Carbon quantum dots in spectrofluorimetric analysis: A comprehensive review of synthesis, mechanisms and multifunctional applications

Carbon quantum dots (CQDs), as a representative nanomaterial, have demonstrated promising applications in fluorescence analysis owing to their unique optical properties, low cytotoxicity and exceptional biocompatibility. This review systematically summarizes recent advances in synthesis strategies, detection mechanisms and applications of CQDs for sensing metal ions (e.g., Hg2+, Fe3+, Cu2+), small molecules (e.g., biomolecules, pharmaceuticals, azo dyes) and proteins. Hybridization of CQDs with functional materials has been shown to significantly enhance their photoluminescence properties while optimizing detection sensitivity and selectivity. The article critically examines fundamental detection mechanisms, especially fluorescence quenching and further outlines design strategies for fluorescence probes based on "on-off" switching or ratio signaling. Moreover, current challenges are analyzed, such as the need for synthetic protocol standardization, in-depth exploration of heteroatom-doped CQDs, expansion of detectable analytes and rational design of fluorescence turn-on probes. Future prospects in environmental monitoring, biomedical diagnostics and pharmaceutical analysis are also highlighted. This comprehensive review offers critical insights to guide the rational design and application of advanced CQD-based hybrid systems.

Unveiling the Mystery of the Stimulatory Effects of Arecoline: Its Relevance to the Regulation of Neurotransmitters and the Microecosystem in Multi-Ecological Intestinal Sites

The dried ripe seeds and pericarp of Areca catechu L., a palm species, possess significant economic value. Masticating betel nut is also a long-standing and widely prevalent lifestyle habit rooted in history, known for its stimulating effect. This effect stems primarily from arecoline, the principal active compound in betel nut. This study investigates the potential mechanisms underlying the stimulating effects of arecoline, focusing on neurotransmitters, neurotrophic factors, and the microecosystem in multi-ecological intestinal sites. After arecoline intervention in mice, significant changes were observed in locomotor activity. The levels of dopamine (DA) in liver tissue and 5-hydroxytryptamine (5-HT) in brain tissue were significantly reduced. There was a significant increase in microbial activity in the feces and in the level of n-valeric acid in the intestinal content. At the genus level, the relative abundance of Clostridium was significantly reduced, whereas the relative abundances of Helicobacter and Aquincola were markedly increased. Helicobacter, Aquincola, Faecalibaculum, and Liquorilactobacillus were signature genera in the arecoline-treated group. The 5-HT level was significantly negatively correlated with the abundance of the signature genera Aquincola, Helicobacter, and Liquorilactobacillus in the arecoline group. The ingestion of arecoline can alter the behavioral patterns of mice, causing significant changes in the 5-HT levels in brain tissue and exerting regulatory effects on the microecosystem in multi-ecological intestinal sites. These findings will provide a reference for the future development and utilization of betel nut.

Clebopride stimulates 5-HT4-serotonin receptors in the human atrium

Clebopride resembles in its structural formula metoclopramide. Clebopride, an approved drug, is used to treat gastrointestinal diseases. Here, we tested the hypothesis that clebopride like metoclopramide acts as a partial agonist at human cardiac 5-HT4-serotonin-receptors. Clebopride enhanced the force of contraction (FOC) in isolated, electrically stimulated (1 Hz) left atrial preparations (LA) from transgenic mice with cardiac specific overexpression of the human 5-HT4-serotonin receptors (5-HT4-TG). Subsequently applied GR125487 (1 µM), a specific 5-HT4-serotonin-receptor antagonist, diminished this positive inotropic effect (PIE) of clebopride in LA from 5-HT4-TG. Clebopride failed to heighten FOC in LA from littermate wild-type mouse hearts (WT). Clebopride augmented the beating rate in isolated right atrial preparations (RA) from 5-HT4-TG but unable to do so in RA from WT. Clebopride alone (up to 10 µM) failed to augment FOC in isolated electrically stimulated (1Hz) human right atrial preparations (HAP) obtained during open heart surgery from adult patients with severe coronary heart disease. Interestingly, in the presence of the phosphodiesterase III inhibitor cilostamide, clebopride heightened FOC in HAP. GR125487 attenuated this PIE in HAP. Furthermore, when 1 µM serotonin had raised FOC in HAP, additionally applied 10 µM clebopride diminished FOC in HAP. We conclude that clebopride can act as an agonist and as an antagonist at 5-HT4-serotonin receptors in the human atrium.

Bromopride stimulates 5-HT4-serotonin receptors in the human atrium

Bromopride, an analogue of metoclopramide, is approved in some countries to treat gastrointestinal diseases. These therapeutic effects of bromopride are explained by antagonism at D2-dopamine receptors in the gut and the brain. We tested here the hypothesis that bromopride acts as an agonist or antagonist at the human cardiac 5-HT4-serotonin receptors. To this end, the force of contraction (FOC) was measured in isolated human atrial preparations (HAP), in isolated left atrial preparations (LA), and in isolated spontaneously beating right atrial (RA) preparations from mice with cardiac specific overexpression of the human 5-HT4-serotonin receptors (5-HT4-TG). Bromopride concentration dependently increased FOC in LA from 5-HT4-TG. The positive inotropic effect (PIE) of bromopride in LA from 5-HT4-TG was abolished by GR125487, a 5-HT4-serotonin receptor antagonist. Only in the presence of the phosphodiesterase III inhibitor cilostamide did bromopride raise FOC under isometric conditions in HAP. The PIE of 10 µM bromopride in HAP was extinguished by 1 µM GR125487. When serotonin had elevated FOC in HAP, additionally applied bromopride reduced FOC. These data suggest that bromopride is a partial agonist at human cardiac 5-HT4-serotonin receptors.

Right ventricular dysfunction following surgical repair of tetralogy of Fallot: Molecular pathways and therapeutic prospects

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease (CHD). Although surgical correction of TOF is possible, patients often face challenges related to right ventricle dysfunction (RVD) post-surgery, which can significantly impact their long-term survival. The causes of RVD in TOF patients are complex, involving both the unique structural characteristics of the TOF heart and damage resulting from surgical interventions. Residual anatomical issues following TOF repair are often unavoidable, placing the RV under stress and leading to the activation of multiple molecular pathways. This review comprehensively outlines the causes of RVD in patients after TOF surgery, particularly focusing the molecular pathways that contribute to RVD, including established signaling pathways as well as emerging pathways identified through transcriptomic analysis of RV myocardium in TOF patients. We also highlight the features of these molecular pathways concerning RVD, as well as the influence of gender disparities on these molecular pathways. By interpreting the causes and molecular mechanisms underlying RVD after TOF surgery, this review provides new insights for managing RVD in repaired TOF, potentially paving the way for targeted therapies aimed at improving long-term outcomes for those affected by RVD.

Contractile effects of stimulation of D1-dopamine receptors in the isolated human atrium

Dopamine receptors have been claimed not to directly increase contractility in the human heart. Therefore, we performed contraction experiments in isolated electrically driven human atrial preparations (HAP). For comparison, we performed contraction experiments with left atrial preparations of transgenic mice which harbor a cardiac overexpression of human D1-dopamine receptors (D1-TG). In D1-TG, first we noted that dopamine (10 nM-10 µM cumulatively applied) in the presence of propranolol exerted a concentration- and time-dependent positive inotropic effect in D1-TG. In a similar fashion, dopamine increased force of contraction in the presence of 0.4 µM propranolol in HAP and these effects were amplified by pre-treatment with inhibitor of phosphodiesterase III (1 µM) cilostamide. Moreover, contractile effects of dopamine in the presence of propranolol 0.4 µM in HAP were antagonized by odapipam, haloperidol, or raclopride. Ten micromolars of fenoldopam in the presence of cilostamide increased force of contraction in HAP and this effect was antagonized by SCH 23390. We conclude that stimulation of human D1-dopamine receptors can increase force of contraction in the HAP.

CORUM in 2024: protein complexes as drug targets

CORUM (https://mips.helmholtz-muenchen.de/corum/) is a public database that offers comprehensive information about mammalian protein complexes, including their subunits, functions and associations with human diseases. The newly released CORUM 5.0, encompassing 7193 protein complexes, is the largest dataset of manually curated mammalian protein complexes publicly available. This update represents the most significant upgrade to the database in >15 years. At present, the molecular processes in cells that are influenced by drugs are only incompletely understood. In this latest release, we have begun systematically investigating the impact of drugs on protein complexes. Our studies are based on a dataset from DrugCentral comprising 725 protein drug targets with approved drugs and known mechanisms of action. To date, we have identified 1975 instances from the literature where a drug affects the formation and/or function of a protein complex. Numerous examples highlight the crucial role of understanding drug-protein complex relationships in drug efficacy. The expanded dataset and the inclusion of drug effects on protein complexes are expected to significantly enhance the utility and application potential of CORUM 5.0 in fields such as network medicine and pharmacological research.

Unraveling the Molecular Determinants of Catalytic Efficiency and Substrate Specificity in l-Amino Acid Decarboxylases

l-Tryptophan decarboxylase (TDC) and l-3,4-dihydroxyphenylalanine decarboxylase (DDC) catalyze the decarboxylation of l-tryptophan, 5-hydroxytryptophan, and l-3,4-dihydroxyphenylalanine. In this study, we analyzed the amino acid compositions of the substrate-binding pockets of TDC from Catharanthus roseus (CrTDC) and DDC from Sus scrofa (SsDDC), explored the specificity of key amino acids within these pockets, and elucidated mechanisms influencing substrate selectivity and catalytic activity in both enzymes, using whole-cell catalysis to screen mutants and determine enzymatic kinetic parameters. The results demonstrated that residues Ala-103 and Val-122 in CrTDC, along with their corresponding sites Thr-82 and Ile-101 in SsDDC, significantly influence substrate selectivity and catalytic efficiency. Molecular dynamics simulations revealed that substrate selectivity and catalytic efficiency depends on the nucleophilic attack distance between the substrate's amino group and the C4' of pyridoxal 5'-phosphate. This study elucidates the catalytic mechanisms and structural bases of TDC and DDC, guiding enhancements in the related aromatic monoamine biosynthesis.

The G4 resolvase Dhx36 modulates cardiomyocyte differentiation and ventricular conduction system development

Extensive genetic studies have elucidated cardiomyocyte differentiation and associated gene networks using single-cell RNA-seq, yet the intricate transcriptional mechanisms governing cardiac conduction system (CCS) development and working cardiomyocyte differentiation remain largely unexplored. Here we show that mice deleted for Dhx36 (encoding the Dhx36 helicase) in the embryonic or neonatal heart develop overt dilated cardiomyopathy, surface ECG alterations related to cardiac impulse propagation, and (in the embryonic heart) a lack of a ventricular conduction system (VCS). Heart snRNA-seq and snATAC-seq reveal the role of Dhx36 in CCS development and in the differentiation of working cardiomyocytes. Dhx36 deficiency directly influences cardiomyocyte gene networks by disrupting the resolution of promoter G-quadruplexes in key cardiac genes, impacting cardiomyocyte differentiation and CCS morphogenesis, and ultimately leading to dilated cardiomyopathy and atrioventricular block. These findings further identify crucial genes and pathways that regulate the development and function of the VCS/Purkinje fiber (PF) network.

Effects of dopamine β-hydroxylase inhibition in pressure overload-induced right ventricular failure

Activation of the sympathetic nervous system is observed in pulmonary arterial hypertension patients. This study investigates whether inhibiting the conversion of dopamine into noradrenaline by dopamine β-hydroxylase (DβH) inhibition with BIA 21-5337 improved right ventricular (RV) function or remodeling in pressure overload-induced RV failure. RV failure was induced in male Wistar rats by pulmonary trunk banding (PTB). Two weeks after the procedure, PTB rats were randomized to vehicle (n = 8) or BIA 21-5337 (n = 11) treatment. An additional PTB group treated with ivabradine (n = 11) was included to control for the potential heart rate-reducing effects of BIA 21-5337. A sham group (n = 6) received vehicle treatment. After 5 weeks of treatment, RV function was assessed by echocardiography, magnetic resonance imaging, and invasive pressure-volume measurements before rats were euthanized. RV myocardium was analyzed to evaluate RV remodeling. PTB caused a fourfold increase in RV afterload which led to RV dysfunction, remodeling, and failure. Treatment with BIA 21-5337 reduced adrenal gland DβH activity and 24-h urinary noradrenaline levels confirming relevant physiological response to the treatment. At end-of-study, there were no differences in RV function or RV remodeling between BIA 21-5337 and vehicle-treated rats. In conclusion, treatment with BIA 21-5337 did not have any beneficial-nor adverse-effects on the development of RV failure after PTB despite reduced adrenal gland DβH activity.

Extensive Dysregulation of Phenylalanine Metabolism Is Associated With Stress Hyperphenylalaninemia and 30-Day Death in Critically Ill Patients With Acute Decompensated Heart Failure

BACKGROUND

Stress hyperphenylalaninemia predicts elevated mortality rates in patients with acute decompensated heart failure (ADHF). This study investigated the metabolic pathways underlying this association and identified a unique metabolic phenotype underlying the association between stress hyperphenylalaninemia and adverse outcomes in ADHF.

METHODS AND RESULTS

This was a retrospective cohort study. We enrolled 120 patients with ADHF in an intensive care unit (60 with a phenylalanine level ≥112 μM, 60 with a phenylalanine level <112 μM), and 30 controls. Plasma phenylalanine-derived metabolites were measured, and participants were evaluated for 30-day death. Patients with ADHF had extensive activations of the alternative pathways for metabolizing phenylalanine, leading to the levels of phenylalanine-derived downstream metabolites 1.5 to 6.1 times higher in patients with ADHF than in the controls (all P<0.001). Extensive dysregulation of these alternative pathways significantly increased phenylalanine levels and contributed to a distinct metabolic phenotype, characterized by increased phenylalanine, tyrosine, homogentisic acid, and succinylacetone levels but decreased benzoic acid and 3,4-dihydroxyphenylalanine levels. Throughout the 30-day follow-up period, 47 (39.2%) patients died. This distinct metabolic phenotype was associated with an increased mortality rate (odds ratio, 1.59 [95% CI, 1.27-1.99]; P<0.001). A multivariable analysis confirmed the independent association of this metabolic phenotype, in addition to phenylalanine and tyrosine levels, with 30-day death.

CONCLUSIONS

In patients with ADHF, extensive dysregulation of the alternative pathways for metabolizing phenylalanine was correlated with stress hyperphenylalaninemia and a distinct metabolic phenotype on the phenylalanine-tyrosine-homogentisic acid-succinylacetone axis. Both stress hyperphenylalaninemia and metabolic dysregulation on this axis were associated with poor outcomes.

Genetics of posttraumatic stress disorder and cardiovascular conditions using Life's Essential 8, Electronic Health Records, and Heart Imaging

BACKGROUND

Patients with post-traumatic stress disorder (PTSD) experience higher risk of adverse cardiovascular (CV) outcomes. This study explores shared loci, and genes between PTSD and CV conditions from three major domains: CV diagnoses from electronic health records (CV-EHR), cardiac and aortic imaging, and CV health behaviors defined in Life's Essential 8 (LE8).

METHODS

We used genome-wide association study (GWAS) of PTSD (N=1,222,882), 246 CV diagnoses based on EHR data from Million Veteran Program (MVP; N=458,061), UK Biobank (UKBB; N=420,531), 82 cardiac and aortic imaging traits (N=26,893), and GWAS of traits defined in the LE8 (N = 282,271 ~ 1,320,016). Shared loci between PTSD and CV conditions were identified using local genetic correlations (rg), and colocalization (shared causal variants). Overlapping genes between PTSD and CV conditions were identified from genetically regulated proteome expression in brain and blood tissues, and subsequently tested to identify functional pathways and gene-drug targets. Epidemiological replication of EHR-CV diagnoses was performed in AllofUS cohort (AoU; N=249,906).

RESULTS

Among the 76 PTSD-susceptibility risk loci, 33 loci exhibited local rg with 45 CV-EHR traits (|rg|≥0.4), four loci with eight heart imaging traits(|rg|≥0.5), and 44 loci with LE8 factors (|rg|≥0.36) in MVP. Among significantly correlated loci, we found shared causal variants (colocalization probability > 80%) between PTSD and 17 CV-EHR (in MVP) at 11 loci in MVP, that also replicated in UKBB and/or other cohorts. Of the 17 traits, the observational analysis in the AoU showed PTSD was associated with 13 CV-EHR traits after accounting for socioeconomic factors and depression diagnosis. PTSD colocalized with eight heart imaging traits on 2 loci and with LE8 factors on 31 loci. Leveraging blood and brain proteome expression, we found 33 and 122 genes, respectively, shared between PTSD and CVD. Blood proteome genes were related to neuronal and immune processes, while the brain proteome genes converged on metabolic and calcium-modulating pathways (FDR p <0.05). Drug repurposing analysis highlighted DRD2, NOS1, GFAP, and POR as common targets of psychiatric and CV drugs.

CONCLUSION

PTSD-CV comorbidities exhibit shared risk loci, and genes involved in tissue-specific regulatory mechanisms.

Initial characterization of a transgenic mouse with overexpression of the human D1-dopamine receptor in the heart

Dopamine can exert effects in the mammalian heart via five different dopamine receptors. There is controversy whether dopamine receptors increase contractility in the human heart. Therefore, we have generated mice that overexpress the human D1-dopamine receptor in the heart (D1-TG) and hypothesized that dopamine increases force of contraction and beating rate compared to wild-type mice (WT). In D1-TG hearts, we ascertained the presence of D1-dopamine receptors by autoradiography using [3H]SKF 38393. The mRNA for human D1-dopamine receptors was present in D1-TG hearts and absent in WT. We detected by in-situ-hybridization mRNA for D1-dopamine receptors in atrial and ventricular D1-TG cardiomyocytes compared to WT but also in human atrial preparations. We noted that in the presence of 10 µM propranolol (to antagonize β-adrenoceptors), dopamine alone and the D1- and D5-dopamine receptor agonist SKF 38393 (0.1-10 µM cumulatively applied) exerted concentration- and time-dependent positive inotropic effects and positive chronotropic effects in left or right atrial preparations from D1-TG. The positive inotropic effects of SKF 38393 in left atrial preparations from D1-TG led to an increased rate of relaxation and accompanied by and probably caused by an augmented phosphorylation state of the inhibitory subunit of troponin. In the presence of 0.4 µM propranolol, 1 µM dopamine could increase left ventricular force of contraction in isolated perfused hearts from D1-TG. In this model, we have demonstrated a positive inotropic and chronotropic effect of dopamine. Thus, in principle, the human D1-dopamine receptor can couple to contractility in the mammalian heart.

An Ultramicroelectrode Electrochemistry and Surface Plasmon Resonance Coupling Method for Cell Exocytosis Study

Exocytosis of a single cell has been extensively researched in recent years due to its close association with numerous diseases. However, current methods only investigate exocytosis at either the single-cell or multiple-cell level, and a method for simultaneously studying exocytosis at both levels has yet to be established. In this study, a combined device incorporating ultramicroelectrode (UME) electrochemistry and surface plasmon resonance (SPR) was developed, enabling the simultaneous monitoring of single-cell and multiple-cell exocytosis. PC12 cells were cultured directly on the SPR sensing Au film, with a carboxylated carbon nanopipette (c-CNP) electrode employed for electrochemical detection in the SPR reaction cell. Upon exocytosis, the released dopamine diffuses onto the inner wall of c-CNP, undergoing an electrochemical reaction to generate a current peak. Concurrently, exocytosis can also induce changes in the refractive index of the Au film surface, leading to the SPR signal. Consequently, the device enables real-time monitoring of exocytosis from both single and multiple cells with a high spatiotemporal resolution. The c-CNP electrode exhibited excellent resistance to protein contamination, high sensitivity for dopamine detection, and the capability to continuously monitor dopamine exocytosis over an extended period. Analysis of both SPR and electrochemical signals revealed a positive correlation between changes in the SPR signal and the frequency of exocytosis. This study introduces a novel method and platform for the simultaneous investigation of single-cell and multiple-cell exocytosis.

A PEDOT: PSS/GO fiber microelectrode fabricated by microfluidic spinning for dopamine detection in human serum and PC12 cells

Rapid and accurate in situ determination of dopamine is of great significance in the study of neurological diseases. In this work, poly (3,4-ethylenedioxythiophene): poly (styrenesulfonic acid) (PEDOT: PSS)/graphene oxide (GO) fibers were fabricated by an effective method based on microfluidic wet spinning technology. The composite microfibers with stratified and dense arrangement were continuously prepared by injecting PEDOT: PSS and GO dispersion solutions into a microfluidic chip. PEDOT: PSS/GO fiber microelectrodes with high electrochemical activity and enhanced electrochemical oxidation activity of dopamine were constructed by controlling the structure composition of the microfibers with varying flow rate. The fabricated fiber microelectrode had a low detection limit (4.56 nM) and wide detection range (0.01-8.0 µM) for dopamine detection with excellent stability, repeatability, and reproducibility. In addition, the PEDOT: PSS/GO fiber microelectrode prepared was successfully used for the detection of dopamine in human serum and PC12 cells. The strategy for the fabrication of multi-component fiber microelectrodes is a new and effective approach for monitoring the intercellular neurotransmitter dopamine and has high potential as an implantable neural microelectrode.

Optical coherence tomography as a potential surrogate marker of dopaminergic modulation across the life span

The retina has been considered a "window to the brain" and shares similar innervation by the dopaminergic system with the cortex in terms of an unequal distribution of D1 and D2 receptors. Here, we provide a comprehensive overview that Optical Coherence Tomography (OCT), a non-invasive imaging technique, which provides an "in vivo" representation of the retina, shows promise to be used as a surrogate marker of dopaminergic neuromodulation in cognition. Overall, most evidence supports reduced retinal thickness in individuals with dopaminergic dysregulation (e.g., patients with Parkinson's Disease, non-demented older adults) and with poor cognitive functioning. By using the theoretical framework of metacontrol, we derive hypotheses that retinal thinning associated to decreased dopamine (DA) levels affecting D1 families, might lead to a decrease in the signal-to-noise ratio (SNR) affecting cognitive persistence (depending on D1-modulated DA activity) but not cognitive flexibility (depending on D2-modulated DA activity). We argue that the use of OCT parameters might not only be an insightful for cognitive neuroscience research, but also a potentially effective tool for individualized medicine with a focus on cognition. As our society progressively ages in the forthcoming years and decades, the preservation of cognitive abilities and promoting healthy aging will hold of crucial significance. OCT has the potential to function as a swift, non-invasive, and economical method for promptly recognizing individuals with a heightened vulnerability to cognitive deterioration throughout all stages of life.

Effect of caffeine-chitosan nanoparticles and α-lipoic acid on the cardiovascular changes induced in rat model of obesity

The current research aims to study the therapeutic efficacy of alpha-lipoic acid (α-LA) and caffeine-loaded chitosan nanoparticles (Caf-CNs) against cardiovascular complications induced by obesity. Rats were divided randomly into: control, high fat diet (HFD) induced obesity rat model, obese rats treated with α-LA and/or Caf-CNs. Triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) as well as activities of lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) significantly increased in the serum of obese rats. In addition, plasma atherogenic index, atherogenic coefficient and Castelli's risk indices I and II showed a significant increase. Additionally, levels of malondialdehyde (MDA) and nitric oxide (NO) and activity of monoamine oxidase (MAO) were significantly elevated in heart tissues of obese rats. However, cardiac Na+/K+-ATPase and acetylcholinesterase (AchE) activities and reduced glutathione (GSH), serotonin (5-HT), norepinephrine (NE) and dopamine (DA) as well as serum high-density lipoprotein cholesterol (HDL-C) were significantly reduced in obese rats. Treatment with α-LA and/or Caf-CNs ameliorated almost all the biochemical and histopathological alterations caused by obesity. In conclusion, the present data revealed that α-LA and/or Caf-CNs may be an effective therapeutic approach against cardiac complications caused by obesity through their antilipemic, anti-atherogenic, antioxidant, and anti-inflammatory activities.

Effects of hallucinogenic drugs on the human heart

Hallucinogenic drugs are used because they have effects on the central nervous system. Their hallucinogenic effects probably occur via stimulation of serotonin receptors, namely, 5-HT2A-serotonin receptors in the brain. However, a close study reveals that they also act on the heart, possibly increasing the force of contraction and beating rate and may lead to arrhythmias. Here, we will review the inotropic and chronotropic actions of bufotenin, psilocin, psilocybin, lysergic acid diethylamide (LSD), ergotamine, ergometrine, N,N-dimethyltryptamine, and 5-methoxy-N,N-dimethyltryptamine in the human heart.

Dopamine in the Regulation of Glucose Homeostasis, Pathogenesis of Type 2 Diabetes, and Chronic Conditions of Impaired Dopamine Activity/Metabolism: Implication for Pathophysiological and Therapeutic Purposes

Dopamine regulates several functions, such as voluntary movements, spatial memory, motivation, sleep, arousal, feeding, immune function, maternal behaviors, and lactation. Less clear is the role of dopamine in the pathophysiology of type 2 diabetes mellitus (T2D) and chronic complications and conditions frequently associated with it. This review summarizes recent evidence on the role of dopamine in regulating insular metabolism and activity, the pathophysiology of traditional chronic complications associated with T2D, the pathophysiological interconnection between T2D and chronic neurological and psychiatric disorders characterized by impaired dopamine activity/metabolism, and therapeutic implications. Reinforcing dopamine signaling is therapeutic in T2D, especially in patients with dopamine-related disorders, such as Parkinson's and Huntington's diseases, addictions, and attention-deficit/hyperactivity disorder. On the other hand, although specific trials are probably needed, certain medications approved for T2D (e.g., metformin, pioglitazone, incretin-based therapy, and gliflozins) may have a therapeutic role in such dopamine-related disorders due to anti-inflammatory and anti-oxidative effects, improvement in insulin signaling, neuroinflammation, mitochondrial dysfunction, autophagy, and apoptosis, restoration of striatal dopamine synthesis, and modulation of dopamine signaling associated with reward and hedonic eating. Last, targeting dopamine metabolism could have the potential for diagnostic and therapeutic purposes in chronic diabetes-related complications, such as diabetic retinopathy.

Multitargeting in cardioprotection: An example of biaromatic compounds

A multitarget drug design approach is actively developing in modern medicinal chemistry and pharmacology, especially with regard to multifactorial diseases such as cardiovascular diseases, cancer, and neurodegenerative diseases. A detailed study of many well-known drugs developed within the single-target approach also often reveals additional mechanisms of their real pharmacological action. One of the multitarget drug design approaches can be the identification of the basic pharmacophore models corresponding to a wide range of the required target ligands. Among such models in the group of cardioprotectors is the linked biaromatic system. This review develops the concept of a "basic pharmacophore" using the biaromatic pharmacophore of cardioprotectors as an example. It presents an analysis of possible biological targets for compounds corresponding to the biaromatic pharmacophore and an analysis of the spectrum of biological targets for the five most known and most studied cardioprotective drugs corresponding to this model, and their involvement in the biological effects of these drugs.

Inflammation, Dopaminergic Brain and Bilirubin

Dopamine is a well-known neurotransmitter due to its involvement in Parkinson's disease (PD). Dopamine is not only involved in PD but also controls multiple mental and physical activities, such as the pleasure of food, friends and loved ones, music, art, mood, cognition, motivation, fear, affective disorders, addiction, attention deficit disorder, depression, and schizophrenia. Dopaminergic neurons (DOPAn) are susceptible to stressors, and inflammation is a recognized risk for neuronal malfunctioning and cell death in major neurodegenerative diseases. Less is known for non-neurodegenerative conditions. Among the endogenous defenses, bilirubin, a heme metabolite, has been shown to possess important anti-inflammatory activity and, most importantly, to prevent DOPAn demise in an ex vivo model of PD by acting on the tumor necrosis factor-alpha (TNFα). This review summarizes the evidence linking DOPAn, inflammation (when possible, specifically TNFα), and bilirubin as an anti-inflammatory in order to understand what is known, the gaps that need filling, and the hypotheses of anti-inflammatory strategies to preserve dopamine homeostasis with bilirubin included.