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

Treatments for weight gain in schizophrenia

PURPOSE OF REVIEW

Obesity and related metabolic disorders are extremely common in psychiatric patients, particularly in those with schizophrenia. Elucidating this link's neurobiology may inform clinicians and researchers of rational therapeutic approaches necessary to optimize clinical outcomes.

RECENT FINDINGS

Current literature highlights the pivotal role of the inflammation-oxidative stress-insulin resistance loop in the pathophysiology of both metabolic and neuropsychiatric disorders. The concept of 'diabetophrenia' is put forward to highlight the overlapping neurobiological mechanisms underlying metabolic dysfunction and schizophrenia symptoms. Innovative treatments, including the combination of xanomeline with trospium and incretin-based medicines, demonstrate encouraging potential in addressing such complex health challenges.

SUMMARY

The nuanced dynamics of chronic inflammation and psychiatric symptomatology underscore the significance of addressing both metabolic and mental health factors in a cohesive fashion while considering unique psychosocial contexts, dietary preferences, and lifestyle choices. A multidisciplinary strategy is essential for incorporating counseling, dietary interventions, behavioral therapies, and pharmacotherapy into the management of schizophrenia. The ensuing enhanced collaboration among healthcare professionals may render obsolete the prevailing siloed conceptualizations of mental disorders, opening new vistas for generating synergistic insights into the mind-body systems and leading to improved health and quality of life for patients with schizophrenia and other psychiatric conditions.

Bromocriptine for Idiopathic Intracranial Hypertension: A Retrospective Multicenter Cohort Study

Introduction

Idiopathic Intracranial Hypertension (IIH) is a disorder characterized by elevated intracranial pressure without an identifiable cause, commonly affecting young obese women. Current treatment strategies, including weight loss, acetazolamide, and surgical interventions, have limitations due to side effects, adherence challenges, and potential complications. Bromocriptine, a dopamine D2 receptor agonist, has emerged as a potential novel therapy due to its metabolic effects. This study aims to evaluate the safety and efficacy of bromocriptine in IIH management through a retrospective cohort analysis.

Methods

A retrospective analysis was conducted, focusing on patients with IIH. Propensity score matching was applied to balance baseline characteristics, including age, sex, race, and BMI, between the bromocriptine and control groups. Key outcome measures, papilledema, headache severity, refractory IIH status, and acetazolamide dose dependency, were assessed at multiple follow-up intervals.

Results

The bromocriptine group demonstrated significant improvement in papilledema and headache severity over 24 months, with early effects observed at one month. There was a marked reduction in refractory IIH (30.66% lower incidence at 24 months, p<0.0001) and reduced dependency on acetazolamide from three months onward (p=0.0246). The safety profile was favorable, with comparable adverse event rates to controls, although allergic skin reactions were noted in the bromocriptine group.

Conclusion

Bromocriptine shows promise as an effective and safe therapeutic option for IIH, with sustained improvement in clinical parameters and reduced reliance on conventional treatment. Future randomized controlled trials are needed to confirm these findings and explore optimal dosing strategies.

Dopamine receptor D2 (DRD2) TaqIA gene polymorphism and acute risperidone-induced changes in body weight, plasma glucose and lipid profile

There are indications that the transient blockade of the dopamine receptor D2 (DRD2) by atypical antipsychotics such as risperidone is related to their metabolic side effects. We, therefore, examined the relationship between TaqIA polymorphism of the DRD2 gene and acute risperidone-induced metabolic changes. We recruited 153 newly diagnosed patients with psychotic disorders (71 males and 82 females) from the Federal Neuropsychiatric Hospital, Yaba, Lagos, Nigeria. Body weight, fasting blood glucose (FBG), triglycerides (TG), total cholesterol (TChol), low-density lipoprotein cholesterol (LDLChol), and high-density lipoprotein cholesterol (LDLChol) were all determined at baseline and the end of 6 weeks of administration of risperidone (2 mg twice daily). DNA was also extracted from peripheral blood, and genotyping was carried out using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The relationship between the mean changes in the metabolic indices and the DRD2 TaqIA genotype was statistically determined. The frequencies of the A1A1, A1A2, and A2A2 were 0.229, 0.412, and 0.360, respectively. However, the population was not in Hardy-Weinberg equilibrium (χ2 = 4.023, p < 0.01). The mean weight change and the mean changes in FBG, TG, TChol, and LDLChol were significantly (p < 0.05) higher among participants with the A1A1 genotype, followed by the heterozygous (A1A2) participants and lowest among those homozygous for the A2 allele. However, there was no significant difference in the mean change in HDLChol across all genotype groups. The DRD2 TaqIA1 allele is associated with higher risperidone-induced weight gain and metabolic changes among Nigerians.

The Role of Dopamine in Neurological, Psychiatric, and Metabolic Disorders and Cancer: A Complex Web of Interactions

Dopamine, a key neurotransmitter in the central nervous system, is essential for regulating a wide range of physiological processes, including motor control, reward processing, mood regulation, and decision-making [...].

Dopamine Dysregulation in Reward and Autism Spectrum Disorder

Autism spectrum disorder (ASD) is primarily characterized by core deficits in social skills, communication, and cognition and by repetitive stereotyped behaviors. These manifestations are variable between individuals, and ASD pathogenesis is complex, with over a thousand implicated genes, many epigenetic factors, and multiple environmental influences. The mesolimbic dopamine (DA) mediated brain reward system is held to play a key role, but the rapidly expanding literature reveals intricate, nuanced signaling involving a wide array of mesolimbic loci, neurotransmitters and receptor subtypes, and neuronal variants. How altered DA signaling may constitute a downstream convergence of the manifold causal origins of ASD is not well understood. A clear working framework of ASD pathogenesis may help delineate common stages and potential diagnostic and interventional opportunities. Hence, we summarize the known natural history of ASD in the context of emerging data and perspectives to update ASD reward signaling. Then, against this backdrop, we proffer a provisional framework that organizes ASD pathogenesis into successive levels, including (1) genetic and epigenetic changes, (2) disrupted mesolimbic reward signaling pathways, (3) dysregulated neurotransmitter/DA signaling, and finally, (4) altered neurocognitive and social behavior and possible antagonist/agonist based ASD interventions. This subdivision of ASD into a logical progression of potentially addressable parts may help facilitate the rational formulation of diagnostics and targeted treatments.

Unlocking the Potential: Semaglutide's Impact on Alzheimer's and Parkinson's Disease in Animal Models

Semaglutide (SEM), a glucagon-like peptide-1 receptor agonist, has garnered increasing interest for its potential therapeutic effects in neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). This review provides a comprehensive description of SEM's mechanism of action and its effects in preclinical studies of these debilitating conditions. In animal models of AD, SEM has proved beneficial effects on multiple pathological hallmarks of the disease. SEM administration has been associated with reductions in amyloid-beta plaque deposition and mitigation of neuroinflammation. Moreover, SEM treatment has been shown to ameliorate behavioral deficits related to anxiety and social interaction. SEM-treated animals exhibit improvements in spatial learning and memory retention tasks, as evidenced by enhanced performance in maze navigation tests and novel object recognition assays. Similarly, in animal models of PD, SEM has demonstrated promising neuroprotective effects through various mechanisms. These include modulation of neuroinflammation, enhancement of mitochondrial function, and promotion of neurogenesis. Additionally, SEM has been shown to improve motor function and ameliorate dopaminergic neuronal loss, offering the potential for disease-modifying treatment strategies. Overall, the accumulating evidence from preclinical studies suggests that SEM holds promise as a novel therapeutic approach for AD and PD. Further research is warranted to elucidate the underlying mechanisms of SEM's neuroprotective effects and to translate these findings into clinical applications for the treatment of these devastating neurodegenerative disorders.

Assessing the Safety and Therapeutic Efficacy of Cannabidiol Lipid Nanoparticles in Alleviating Metabolic and Memory Impairments and Hippocampal Histopathological Changes in Diabetic Parkinson's Rats

Diabetic Parkinson's disease (DP) is a progressive neurodegenerative disease with metabolic syndrome that is increasing worldwide. Emerging research suggests that cannabidiol (CBD) is a neuropharmacological compound that acts against this disease, especially CBD in nano-formulation. The safety of cannabidiol lipid nanoparticles (CBD-LNP) was evaluated by assessing in vitro cytotoxicity in neurons and therapeutic outcomes in a DP animal model, including metabolic parameters and histopathology. CBD-LNPs were fabricated by using a microfluidization technique and showed significantly lower cytotoxicity than the natural form of CBD. The DP rats were induced by streptozotocin followed by a 4-week injection of MPTP with a high-fat diet. Rats were treated orally with a vehicle, CBD, CBD-LNP, or levodopa for 4 weeks daily. As a result, vehicle-treated rats exhibited metabolic abnormalities, decreased striatal dopamine levels, and motor and memory deficits. CBD-LNP demonstrated reduced lipid profiles, enhanced insulin secretion, and restored dopamine levels compared to CBD in the natural form. CBD-LNP also had comparable efficacy to levodopa in ameliorating motor deficits and memory impairment in behavior tests. Interestingly, CBD-LNP presented migration of damaged neuronal cells in the hippocampus more than levodopa. These findings suggest that CBD-LNP holds promise as an intervention addressing both metabolic and neurodegenerative aspects of DP, offering a potential therapeutic strategy.

Development of novel tools for dissection of central versus peripheral dopamine D2-like receptor signaling in dysglycemia

Dopamine (DA) D2-like receptors in both the central nervous system (CNS) and the periphery are key modulators of metabolism. Moreover, disruption of D2-like receptor signaling is implicated in dysglycemia. Yet, the respective metabolic contributions of CNS versus peripheral D2-like receptors including D2 (D2R) and D3 (D3R) receptors remain poorly understood. To address this, we developed new pharmacological tools, D2-like receptor agonists with diminished and delayed blood-brain barrier capability, to selectively manipulate D2R/D3R signaling in the periphery. We designated bromocriptine methiodide (BrMeI), a quaternary methiodide analogue of D2/3R agonist and diabetes drug bromocriptine, as our lead compound based on preservation of D2R/D3R binding and functional efficacy. We then used BrMeI and unmodified bromocriptine to dissect relative contributions of CNS versus peripheral D2R/D3R signaling in treating dysglycemia. Systemic administration of bromocriptine, with unrestricted access to CNS and peripheral targets, significantly improved both insulin sensitivity and glucose tolerance in obese, dysglycemic mice in vivo. In contrast, metabolic improvements were attenuated when access to bromocriptine was restricted either to the CNS through intracerebroventricular administration or delayed access to the CNS via BrMeI. Our findings demonstrate that the coordinated actions of both CNS and peripheral D2-like receptors are required for correcting dysglycemia. Ultimately, the development of a first-generation of drugs designed to selectively target the periphery provides a blueprint for dissecting mechanisms of central versus peripheral DA signaling and paves the way for novel strategies to treat dysglycemia.