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Behavioral and Brain Functions : BBF Nov 2016The association between the dopamine D2 receptor (DRD2) gene and schizophrenia has been studied though no conclusive outcomes have been attained. The aim of this study... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The association between the dopamine D2 receptor (DRD2) gene and schizophrenia has been studied though no conclusive outcomes have been attained. The aim of this study was to perform a systematic review and meta-analysis to explore the relation between three polymorphisms of the DRD2 gene (C957T, TaqI and Ser311Cys) and schizophrenia.
METHODS
The search was made in PubMed and EBSCO databases (up to February 2016). The systematic review included 34 case-control association studies (34 for C957T, 16 for TaqI and 36 for Ser311Cys). The association analysis comprised the allelic, additive, dominant, and recessive genetic models. The meta-analysis was performed following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement.
RESULTS
The meta-analysis showed that TaqI (additive model: OR 0.57, 95% CI 0.30-1.14) and C957T (additive model: OR 0.75, 95% OR 0.58-0.97, recessive model: OR 0.79, 95% CI 0.64-0.98) exert a protective effect against developing schizophrenia. However, the sub-analysis for the C957T variant showed that this polymorphism exhibits a risk factor effect on Chinese individuals (allelic model: OR 1.33, 95% CI 1.04-1.70).
CONCLUSION
Our meta-analysis suggests an association of the DRD2 gene and the risk for schizophrenia, given that TaqI and C957T polymorphisms presented a protective effect against schizophrenia, and in the sub-analyses the C957T variant increased the risk for this disorder in the Chinese population.
Topics: Alleles; Case-Control Studies; Gene Frequency; Genetic Association Studies; Genetic Predisposition to Disease; Humans; Polymorphism, Single Nucleotide; Receptors, Dopamine D2; Risk Factors; Schizophrenia
PubMed: 27829443
DOI: 10.1186/s12993-016-0114-z -
Brain and Behavior Jun 2023Primary generalized dystonia due to the DYT1 gene is an autosomal dominant disorder caused by a GAG deletion on chromosome 9q34. It is a well-defined, genetically... (Review)
Review
BACKGROUND
Primary generalized dystonia due to the DYT1 gene is an autosomal dominant disorder caused by a GAG deletion on chromosome 9q34. It is a well-defined, genetically proven, isolated dystonia syndrome. However, its pathophysiology remains unclear.
OBJECTIVES
This study was aimed at profiling the functional neuroimaging findings in DYT1 dystonia and harmonizing the pathophysiological implications for DYT1 dystonia from the standpoint of different neuroimaging techniques.
METHODS
A systematic review was conducted using identified studies published in English from Medline, PsycINFO, Embase, CINAHL, and the Cochrane Database of Systematic Reviews (CDSR), between 1985 and December 2019 (PROSPERO protocol CRD42018111211).
RESULTS
All DYT1 gene carriers irrespective of clinical penetrance have reduced striatal GABA, dopamine receptors and increased metabolic activity in the lentiform nucleus, supplementary motor area, and cerebellum in addition to an abnormal cerebellothalamocortical pathway. Nonmanifesting carriers on the other hand have a disruption of the distal (thalamocortical) segment and have larger putaminal volumes than manifesting carriers and healthy controls. Activation of the midbrain, thalamus, and sensorimotor cortex was only found in the manifesting carriers.
CONCLUSIONS
Therefore, we propose that DYT1 dystonia is a cerebellostriatothalamocortical network disorder affecting either the structure or function of the different structures or nodes in the network.
Topics: Humans; Dystonia; Dystonic Disorders; Molecular Chaperones; Neuroimaging
PubMed: 37165749
DOI: 10.1002/brb3.3023 -
JAMA Dermatology Aug 2020The association between the use of medications and the development of bullous pemphigoid (BP) is unclear. (Meta-Analysis)
Meta-Analysis
IMPORTANCE
The association between the use of medications and the development of bullous pemphigoid (BP) is unclear.
OBJECTIVE
To assess the associations between previous exposure to certain medications and BP.
DATA SOURCES
For this systematic review and meta-analysis, PubMed, the Cochrane Central Register of Controlled Trials, and Embase were searched for relevant studies from inception to February 20, 2020.
STUDY SELECTION
Case-control or cohort studies and randomized clinical trials that examined the odds or risk of BP in patients with previous medication use were included. No geographic or language limitations were imposed.
DATA EXTRACTION AND SYNTHESIS
The Meta-analysis of Observational Studies in Epidemiology (MOOSE) guideline was followed. The Newcastle-Ottawa Scale was used to evaluate the risk of bias of included observational studies; Cochrane Collaboration's tool was used for randomized clinical trials. Aggregate data were used to conduct a random-effects model meta-analysis if the included studies were sufficiently homogenous. Subgroup analyses were performed for use of various medications of the same category.
MAIN OUTCOMES AND MEASURES
Odds ratio (OR), hazard ratio, and risk ratio of bullous pemphigoid in association with medication use.
RESULTS
This meta-analysis included 13 case-control studies, 1 cohort study, and 1 randomized clinical trial with a total of 285 884 participants. The meta-analysis of case-control studies showed a significant association of BP with previous use of aldosterone antagonists (pooled OR, 1.75; 95% CI, 1.28-2.40), dipeptidyl peptidase 4 inhibitors (pooled OR, 1.92; 95% CI, 1.55-2.38), anticholinergics (pooled OR, 3.12; 95% CI, 1.54-6.33), and dopaminergic medications (pooled OR, 2.03; 95% CI, 1.34-3.05). One cohort study found an increased risk of BP among patients receiving dipeptidyl peptidase 4 inhibitors (hazard ratio, 2.38; 95% CI, 1.16-4.88; P = .02). One trial found a higher occurrence of BP in patients with diabetes receiving linagliptin (0.2% in diabetes group vs 0% in the placebo group).
CONCLUSIONS AND RELEVANCE
The findings of this systematic review and meta-analysis suggest that aldosterone antagonists, dipeptidyl peptidase 4 inhibitors, anticholinergics, and dopaminergic medications are associated with BP. These medications should be judiciously prescribed, particularly in high-risk patients who are elderly and have disabling neurologic disorders.
Topics: Antihypertensive Agents; Cholinergic Antagonists; Dipeptidyl-Peptidase IV Inhibitors; Diuretics; Dopamine Agents; Humans; Hypoglycemic Agents; Mineralocorticoid Receptor Antagonists; Odds Ratio; Pemphigoid, Bullous; Psychotropic Drugs; Risk Factors
PubMed: 32584924
DOI: 10.1001/jamadermatol.2020.1587 -
Translational Psychiatry Jan 2017Disrupted-in-Schizophrenia 1 (DISC1) is a gene known as a risk factor for mental illnesses possibly associated with dopamine impairments. DISC1 is a scaffold protein... (Review)
Review
Disrupted-in-Schizophrenia 1 (DISC1) is a gene known as a risk factor for mental illnesses possibly associated with dopamine impairments. DISC1 is a scaffold protein interacting with proteins involved in the dopamine system. Here we summarise the impact of DISC1 disruption on the dopamine system in animal models, considering its effects on presynaptic dopaminergic function (tyrosine hydroxylase levels, dopamine transporter levels, dopamine levels at baseline and after amphetamine administration) and postsynaptic dopaminergic function (dopamine D1 and D2 receptor levels, dopamine receptor-binding potential and locomotor activity after amphetamine administration). Our findings show that many but not all DISC1 models display (1) increased locomotion after amphetamine administration, (2) increased dopamine levels after amphetamine administration in the nucleus accumbens, and (3) inconsistent basal dopamine levels, dopamine receptor levels and binding potentials. There is also limited evidence for decreased tyrosine hydroxylase levels in the frontal cortex and increased dopamine transporter levels in the striatum but not nucleus accumbens, but these conclusions warrant further replication. The main dopaminergic findings are seen across different DISC1 models, providing convergent evidence that DISC1 has a role in regulating dopaminergic function. These results implicate dopaminergic dysregulation as a mechanism underlying the increased rate of schizophrenia seen in DISC1 variant carriers, and provide insights into how DISC1, and potentially DISC1-interacting proteins such as AKT and GSK-3, could be used as novel therapeutic targets for schizophrenia.
Topics: Amphetamine; Animals; Dopamine; Dopamine Plasma Membrane Transport Proteins; Dopamine Uptake Inhibitors; Locomotion; Mice; Nerve Tissue Proteins; Nucleus Accumbens; Rats; Receptors, Dopamine D1; Receptors, Dopamine D2; Tyrosine 3-Monooxygenase
PubMed: 28140405
DOI: 10.1038/tp.2016.282 -
International Journal of Molecular... Mar 2023Schizophrenia is a severe psychiatric illness affecting almost 25 million people worldwide and is conceptualized as a disorder of synaptic plasticity and brain... (Review)
Review
Canonical and Non-Canonical Antipsychotics' Dopamine-Related Mechanisms of Present and Next Generation Molecules: A Systematic Review on Translational Highlights for Treatment Response and Treatment-Resistant Schizophrenia.
Schizophrenia is a severe psychiatric illness affecting almost 25 million people worldwide and is conceptualized as a disorder of synaptic plasticity and brain connectivity. Antipsychotics are the primary pharmacological treatment after more than sixty years after their introduction in therapy. Two findings hold true for all presently available antipsychotics. First, all antipsychotics occupy the dopamine D2 receptor (D2R) as an antagonist or partial agonist, even if with different affinity; second, D2R occupancy is the necessary and probably the sufficient mechanism for antipsychotic effect despite the complexity of antipsychotics' receptor profile. D2R occupancy is followed by coincident or divergent intracellular mechanisms, implying the contribution of cAMP regulation, β-arrestin recruitment, and phospholipase A activation, to quote some of the mechanisms considered canonical. However, in recent years, novel mechanisms related to dopamine function beyond or together with D2R occupancy have emerged. Among these potentially non-canonical mechanisms, the role of Na channels at the dopamine at the presynaptic site, dopamine transporter (DAT) involvement as the main regulator of dopamine concentration at synaptic clefts, and the putative role of antipsychotics as chaperones for intracellular D2R sequestration, should be included. These mechanisms expand the fundamental role of dopamine in schizophrenia therapy and may have relevance to considering putatively new strategies for treatment-resistant schizophrenia (TRS), an extremely severe condition epidemiologically relevant and affecting almost 30% of schizophrenia patients. Here, we performed a critical evaluation of the role of antipsychotics in synaptic plasticity, focusing on their canonical and non-canonical mechanisms of action relevant to the treatment of schizophrenia and their subsequent implication for the pathophysiology and potential therapy of TRS.
Topics: Humans; Antipsychotic Agents; Dopamine; Schizophrenia; Schizophrenia, Treatment-Resistant; beta-Arrestins
PubMed: 36983018
DOI: 10.3390/ijms24065945 -
Journal of Psychiatry & Neuroscience :... 2024Transcranial magnetic stimulation (TMS) is a noninvasive neurostimulation modality that has been used to study human synaptic plasticity. Leveraging work in ex vivo...
BACKGROUND
Transcranial magnetic stimulation (TMS) is a noninvasive neurostimulation modality that has been used to study human synaptic plasticity. Leveraging work in ex vivo preparations, mechanistically informed pharmacological adjuncts to TMS have been used to improve our fundamental understanding of TMS-induced synaptic plasticity.
METHODS
We systematically reviewed the literature pairing pharmacological adjuncts with TMS plasticity-induction protocols in humans. We searched MEDLINE, PsycINFO, and Embase from 2013 to Mar. 10, 2023. Studies published before 2013 were extracted from a previous systematic review. We included studies using repetitive TMS, theta-burst stimulation, paired associative stimulation, and quadripulse stimulation paradigms in healthy and clinical populations.
RESULTS
Thirty-six studies met our inclusion criteria (28 in healthy and 8 in clinical populations). Most pharmacological agents have targeted the glutamatergic -methyl-d-aspartate (NMDA; 15 studies) or dopamine receptors (13 studies). The NMDA receptor is necessary for TMS-induced plasticity; however, sufficiency has not been shown across protocols. Dopaminergic modulation of TMS-induced plasticity appears to be dose-dependent. The GABAergic, cholinergic, noradrenergic, and serotonergic neurotransmitter systems have small evidence bases supporting modulation of TMS-induced plasticity, as do voltage-gated calcium and sodium channels. Studies in clinical populations suggest that pharmacological adjuncts to TMS may rescue motor cortex plasticity, with implications for therapeutic applications of TMS and a promising clinical trial in depression.
LIMITATIONS
This review is limited by the predominance in the literature of studies with small sample sizes and crossover designs.
CONCLUSION
Pharmacologically enhanced TMS largely parallels findings from ex vivo preparations. As this area expands and novel targets are tested, adequately powered samples in healthy and clinical populations will inform the mechanisms of TMS-induced plasticity in health and disease.
Topics: Humans; Transcranial Magnetic Stimulation; Neuronal Plasticity; Motor Cortex; Dopamine; Calcium; Evoked Potentials, Motor
PubMed: 38359933
DOI: 10.1503/jpn.230090 -
Pharmacological Reviews Oct 2022Transcranial magnetic stimulation (TMS) is a noninvasive neuromodulation tool currently used as a treatment in multiple psychiatric and neurologic disorders. Despite its... (Review)
Review
Changing Cerebral Blood Flow, Glucose Metabolism, and Dopamine Binding Through Transcranial Magnetic Stimulation: A Systematic Review of Transcranial Magnetic Stimulation-Positron Emission Tomography Literature.
Transcranial magnetic stimulation (TMS) is a noninvasive neuromodulation tool currently used as a treatment in multiple psychiatric and neurologic disorders. Despite its widespread use, we have an incomplete understanding of the way in which acute and chronic sessions of TMS affect various neural and vascular systems. This systematic review summarizes the state of our knowledge regarding the effects TMS may be having on cerebral blood flow, glucose metabolism, and neurotransmitter release. Forty-five studies were identified. Several key themes emerged: 1) TMS transiently increases cerebral blood flow in the area under the coil; 2) TMS to the prefrontal cortex increases glucose metabolism in the anterior cingulate cortex of patients with depression; and 3) TMS to the motor cortex and prefrontal cortex decreases dopamine receptor availability in the ipsilateral putamen and caudate respectively. There is, however, a paucity of literature regarding the effects TMS may have on other neurotransmitter and neuropeptide systems of interest, all of which may shed vital light on existing biologic mechanisms and future therapeutic development. SIGNIFICANCE STATEMENT: Transcranial magnetic stimulation (TMS) is a noninvasive neuromodulation tool currently used as a treatment in multiple psychiatric and neurologic disorders. This systematic review summarizes the state of our knowledge regarding the effects TMS on cerebral blood flow, glucose metabolism, and neurotransmitter release.
Topics: Humans; Transcranial Magnetic Stimulation; Dopamine; Tomography, X-Ray Computed; Positron-Emission Tomography; Cerebrovascular Circulation; Glucose
PubMed: 36779330
DOI: 10.1124/pharmrev.122.000579 -
Sleep Attacks in Patients With Parkinson's Disease on Dopaminergic Medications: A Systematic Review.Movement Disorders Clinical Practice Dec 2014Dopaminergic medications are used as first-line treatment for Parkinson's disease (PD). In 1999, a case series was published describing 9 patients who took dopamine... (Review)
Review
Dopaminergic medications are used as first-line treatment for Parkinson's disease (PD). In 1999, a case series was published describing 9 patients who took dopamine agonists (pramipexole or ropinirole) and experienced sudden irresistible sleep attacks. Sleep attacks have subsequently been reported with other dopaminergic medications, including levodopa. Because these symptoms might not be rare and can affect health-related quality of life, we set out to review the prevalence and clinical characteristics of sleep attacks in patients with PD on dopaminergic medications. We conducted a systematic literature review using the terms parkinson* AND dopamine* AND narcolep* OR sleep attack in multiple databases (PubMed, Embase, and PsycINFO). The systematic literature review yielded 23 relevant articles, including nine case reports or case series and 14 original studies. According to the pooled data from the five studies reporting prevalence figures (n = 10,084), sleep attacks occur in 13.0% of patients with PD on dopaminergic medications. Our analysis failed to show significant differences in the Epworth Sleepiness scores between patients with and without sleep attacks (mean difference: 2.92; 95% confidence interval: -0.47-6.31). The I value of 76% indicated high heterogeneity among the studies. Sleep attacks are not a rare occurrence in patients with PD on dopamine agonist treatment. We found conflicting results on whether sleep attacks in PD resemble narcolepsy. The pathophysiology of these symptoms might be related to dopamine D2 and D4 receptor gene polymorphisms. The most effective management strategies were dose reduction and discontinuation of the offending drugs.
PubMed: 30363881
DOI: 10.1002/mdc3.12063 -
Biomolecules Jun 2022Schizophrenia has been conceptualized as a neurodevelopmental disorder with synaptic alterations and aberrant cortical-subcortical connections. Antipsychotics are the... (Review)
Review
Schizophrenia has been conceptualized as a neurodevelopmental disorder with synaptic alterations and aberrant cortical-subcortical connections. Antipsychotics are the mainstay of schizophrenia treatment and nearly all share the common feature of dopamine D2 receptor occupancy, whereas glutamatergic abnormalities are not targeted by the presently available therapies. D-amino acids, acting as N-methyl-D-aspartate receptor (NMDAR) modulators, have emerged in the last few years as a potential augmentation strategy in those cases of schizophrenia that do not respond well to antipsychotics, a condition defined as treatment-resistant schizophrenia (TRS), affecting almost 30-40% of patients, and characterized by serious cognitive deficits and functional impairment. In the present systematic review, we address with a direct and reverse translational perspective the efficacy of D-amino acids, including D-serine, D-aspartate, and D-alanine, in poor responders. The impact of these molecules on the synaptic architecture is also considered in the light of dendritic spine changes reported in schizophrenia and antipsychotics' effect on postsynaptic density proteins. Moreover, we describe compounds targeting D-amino acid oxidase and D-aspartate oxidase enzymes. Finally, other drugs acting at NMDAR and proxy of D-amino acids function, such as D-cycloserine, sarcosine, and glycine, are considered in the light of the clinical burden of TRS, together with other emerging molecules.
Topics: Amino Acids; Antipsychotic Agents; Humans; Neurobiology; Receptors, N-Methyl-D-Aspartate; Schizophrenia; Schizophrenia, Treatment-Resistant
PubMed: 35883465
DOI: 10.3390/biom12070909 -
Schizophrenia Bulletin Nov 2016Although weight gain is a serious but variable adverse effect of antipsychotics that has genetic underpinnings, a comprehensive meta-analysis of pharmacogenetics of... (Meta-Analysis)
Meta-Analysis Review
Although weight gain is a serious but variable adverse effect of antipsychotics that has genetic underpinnings, a comprehensive meta-analysis of pharmacogenetics of antipsychotic-related weight gain is missing. In this review, random effects meta-analyses were conducted for dominant and recessive models on associations of specific single nucleotide polymorphisms (SNP) with prospectively assessed antipsychotic-related weight or body mass index (BMI) changes (primary outcome), or categorical increases in weight or BMI (≥7%; secondary outcome). Published studies, identified via systematic database search (last search: December 31, 2014), plus 3 additional cohorts, including 222 antipsychotic-naïve youth, and 81 and 141 first-episode schizophrenia adults, each with patient-level data at 3 or 4 months treatment, were meta-analyzed. Altogether, 72 articles reporting on 46 non-duplicated samples (n = 6700, mean follow-up = 25.1wk) with 38 SNPs from 20 genes/genomic regions were meta-analyzed (for each meta-analysis, studies = 2-20, n = 81-2082). Eleven SNPs from 8 genes were significantly associated with weight or BMI change, and 4 SNPs from 2 genes were significantly associated with categorical weight or BMI increase. Combined, 13 SNPs from 9 genes (Adrenoceptor Alpha-2A [ADRA2A], Adrenoceptor Beta 3 [ADRB3], Brain-Derived Neurotrophic Factor [BDNF], Dopamine Receptor D2 [DRD2], Guanine Nucleotide Binding Protein [GNB3], 5-Hydroxytryptamine (Serotonin) Receptor 2C [HTR2C], Insulin-induced gene 2 [INSIG2], Melanocortin-4 Receptor [MC4R], and Synaptosomal-associated protein, 25kDa [SNAP25]) were significantly associated with antipsychotic-related weight gain (P-values < .05-.001). SNPs in ADRA2A, DRD2, HTR2C, and MC4R had the largest effect sizes (Hedges' g's = 0.30-0.80, ORs = 1.47-1.96). Less prior antipsychotic exposure (pediatric or first episode patients) and short follow-up (1-2 mo) were associated with larger effect sizes. Individual antipsychotics did not significantly moderate effect sizes. In conclusion, antipsychotic-related weight gain is polygenic and associated with specific genetic variants, especially in genes coding for antipsychotic pharmacodynamic targets.
Topics: Antipsychotic Agents; Humans; Pharmacogenetics; Psychotic Disorders; Weight Gain
PubMed: 27217270
DOI: 10.1093/schbul/sbw058