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Schizophrenia Research. Cognition Dec 2023In a previous meta-analysis, the use of serotonin(5-HT) receptor partial agonists of the azapirone class as an add-on therapy was associated with beneficial effects on...
BACKGROUND
In a previous meta-analysis, the use of serotonin(5-HT) receptor partial agonists of the azapirone class as an add-on therapy was associated with beneficial effects on positive symptoms and attention/processing speed in schizophrenia patients. This meta-analysis builds on that study by examining the effects of adjunctive treatment with 5-HT partial agonists in improving other domains of neurocognitive function in schizophrenia patients.
METHODS
A literature search was performed from 1987 to May 2023 to identify randomized controlled trials. The standardized mean difference (SMD) with 95 % confidence intervals (CI) was calculated when there were two or more studies. Four studies, involving 313 patients, met the inclusion criteria and were used in the analysis.
RESULTS
5-HT partial agonists (buspirone or tandospirone) did not have a significant effect on verbal learning (SMD = 0.08, 95 % CI = -0.31 to 0.47) or working memory (SMD = 0.15, 95 % CI = -0.09 to 0.39). Regarding executive functions (Wisconsin Card Sorting Test), positive but non-significant results were seen with the category number (SMD = 0.26, 95 % CI = -0.81 to 1.32), while non-significant effects were noted for percent preservation errors (SMD = -0.10, 95 % CI = -0.53 to 0.33).
CONCLUSIONS
The absence of any significant benefits in the cognitive domains studied here may have been due to the variance in the concomitant medication (typical vs atypical antipsychotic drugs), the level of cognition at baseline, or other factors. Further studies with various types of 5-HT agonists are warranted to examine the potential cognitive efficacy of stimulating these receptors.
PubMed: 37732133
DOI: 10.1016/j.scog.2023.100290 -
Obesity Reviews : An Official Journal... Nov 2023This systematic review collates studies of dietary or bariatric surgery interventions for obesity using positron emission tomography and single-photon emission computed... (Review)
Review
Effects of bariatric surgery and dietary interventions for obesity on brain neurotransmitter systems and metabolism: A systematic review of positron emission tomography (PET) and single-photon emission computed tomography (SPECT) studies.
This systematic review collates studies of dietary or bariatric surgery interventions for obesity using positron emission tomography and single-photon emission computed tomography. Of 604 publications identified, 22 met inclusion criteria. Twelve studies assessed bariatric surgery (seven gastric bypass, five gastric bypass/sleeve gastrectomy), and ten dietary interventions (six low-calorie diet, three very low-calorie diet, one prolonged fasting). Thirteen studies examined neurotransmitter systems (six used tracers for dopamine DRD2/3 receptors: two each for C-raclopride, F-fallypride, I-IBZM; one for dopamine transporter, I-FP-CIT; one used tracer for serotonin 5-HT receptor, F-altanserin; two used tracers for serotonin transporter, C-DASB or I-FP-CIT; two used tracer for μ-opioid receptor, C-carfentanil; one used tracer for noradrenaline transporter, C-MRB); seven studies assessed glucose uptake using F-fluorodeoxyglucose; four studies assessed regional cerebral blood flow using O-H O (one study also used arterial spin labeling); and two studies measured fatty acid uptake using F-FTHA and one using C-palmitate. The review summarizes findings and correlations with clinical outcomes, eating behavior, and mechanistic mediators. The small number of studies using each tracer and intervention, lack of dietary intervention control groups in any surgical studies, heterogeneity in time since intervention and degree of weight loss, and small sample sizes hindered the drawing of robust conclusions across studies.
Topics: Humans; Positron-Emission Tomography; Tomography, Emission-Computed, Single-Photon; Bariatric Surgery; Brain; Obesity; Neurotransmitter Agents
PubMed: 37699864
DOI: 10.1111/obr.13620 -
Brain Sciences Aug 2023Fear is characterized by distinct behavioral and physiological responses that are essential for the survival of the human species. Fear conditioning (FC) serves as a... (Review)
Review
Fear is characterized by distinct behavioral and physiological responses that are essential for the survival of the human species. Fear conditioning (FC) serves as a valuable model for studying the acquisition, extinction, and expression of fear. The serotonin (5-hydroxytryptamine, 5-HT) system is known to play a significant role in emotional and motivational aspects of human behavior, including fear learning and expression. Accumulating evidence from both animal and human studies suggests that brain regions involved in FC, such as the amygdala, hippocampus, and prefrontal cortex, possess a high density of 5-HT receptors, implicating the crucial involvement of serotonin in aversive learning. Additionally, studies exploring serotonin gene polymorphisms have indicated their potential influence on FC. Therefore, the objective of this work was to review the existing evidence linking 5-HT with fear learning and memory in humans. Through a comprehensive screening of the PubMed and Web of Science databases, 29 relevant studies were included in the final review. These studies investigated the relationship between serotonin and fear learning using drug manipulations or by studying 5-HT-related gene polymorphisms. The results suggest that elevated levels of 5-HT enhance aversive learning, indicating that the modulation of serotonin 5-HT2A receptors regulates the expression of fear responses in humans. Understanding the role of this neurochemical messenger in associative aversive learning can provide insights into psychiatric disorders such as anxiety and post-traumatic stress disorder (PTSD), among others.
PubMed: 37626553
DOI: 10.3390/brainsci13081197 -
Nutrients Jun 2023Evidence is emerging for the role of intestinal tryptophan metabolism in the development of inflammatory bowel disease (IBD). In order to identify the role of altered... (Meta-Analysis)
Meta-Analysis Review
The Involvement of Intestinal Tryptophan Metabolism in Inflammatory Bowel Disease Identified by a Meta-Analysis of the Transcriptome and a Systematic Review of the Metabolome.
Evidence is emerging for the role of intestinal tryptophan metabolism in the development of inflammatory bowel disease (IBD). In order to identify the role of altered intestinal tryptophan metabolism in IBD pathogenesis, a meta-analysis of the transcriptome was performed to identify differentially expressed genes involved in the tryptophan metabolism pathways in intestinal biopsies of IBD as compared to non-IBD controls. Moreover, a systematic review of the metabolome was performed to identify the concurrent changes in tryptophan metabolites. Integration of the transcriptome and metabolome identified various alterations in intestinal tryptophan metabolism during active disease in IBD patients, including decreased intestinal tryptophan absorption, enhanced kynurenine pathway, increased interstitial serotonin availability, changed indole pathway, and activated aryl hydrocarbon receptor signaling. Therefore, a network of intestinal tryptophan metabolism pathways in IBD could be established, helping to assess the potential of genes and metabolites involved in these pathways as diagnostic markers and targets for IBD management.
Topics: Humans; Tryptophan; Transcriptome; Inflammatory Bowel Diseases; Intestines; Metabolome
PubMed: 37447212
DOI: 10.3390/nu15132886 -
East Asian Archives of Psychiatry :... Jun 2023Clozapine is a potent antipsychotic medication with a complex receptor profile. It is reserved for treatment-resistant schizophrenia. We systematically reviewed studies...
OBJECTIVE
Clozapine is a potent antipsychotic medication with a complex receptor profile. It is reserved for treatment-resistant schizophrenia. We systematically reviewed studies of non-psychosis symptoms of clozapine withdrawal.
METHODS
CINAHL, Medline, PsycINFO, PubMed, and the Cochrane Database of Systematic Reviews were searched using the keywords 'clozapine,' and 'withdrawal,' or 'supersensitivity,' 'cessation,' 'rebound,' or 'discontinuation'. Studies related to non-psychosis symptoms after clozapine withdrawal were included.
RESULTS
Five original studies and 63 case reports / series were included in analysis. In 195 patients included in the five original studies, approximately 20% experienced non-psychosis symptoms following discontinuation of clozapine. In 89 patients in four of the studies, 27 experienced cholinergic rebound, 13 exhibited extrapyramidal symptoms (including tardive dyskinesia), and three had catatonia. In 63 case reports / series included, 72 patients with non-psychosis symptoms were reported, which were catatonia (n=30), dystonia or dyskinesia (n=17), cholinergic rebound (n=11), serotonin syndrome (n=4), mania (n=3), insomnia (n=3), neuroleptic malignant syndrome (NMS) [n=3, one of them had both catatonia and NMS], and de novo obsessive compulsive symptoms (n=2). Restarting clozapine appeared to be the most effective treatment.
CONCLUSIONS
Non-psychosis symptoms following clozapine withdrawal have important clinical implications. Clinicians should be aware of the possible presentations of symptoms to ensure early recognition and management. Further research is warranted to better characterise the prevalence, risk factors, prognosis, and optimal drug dosing for each withdrawal symptom.
Topics: Humans; Antipsychotic Agents; Catatonia; Cholinergic Agents; Clozapine; Schizophrenia; Substance Withdrawal Syndrome
PubMed: 37400227
DOI: 10.12809/eaap2261 -
Ondansetron-induced QT prolongation among various age groups: a systematic review and meta-analysis.The Egyptian Heart Journal : (EHJ) :... Jul 2023Ondansetron is a selective 5-hydroxytryptamine type 3 serotonin-receptor antagonist with antiemetic properties used inadvertently in the emergency department for...
BACKGROUND
Ondansetron is a selective 5-hydroxytryptamine type 3 serotonin-receptor antagonist with antiemetic properties used inadvertently in the emergency department for controlling nausea. However, ondansetron is linked with a number of adverse effects, including prolongation of the QT interval. Therefore, the purpose of this meta-analysis was to assess the occurrence of QT prolongation in pediatric, adult, and elderly patients receiving oral or intravenously administered ondansetron.
METHODS
A thorough electronic search was conducted on PubMed (Medline) and Cochrane Library from the databases' inception to August 10, 2022. Only those studies were considered in which ondansetron was administered orally or intravenously to participants for the treatment of nausea and vomiting. The prevalence of QT prolongation in multiple predefined age groups was the outcome variable. Analyses were conducted using Review manager 5.4 (Cochrane collaboration, 2020).
RESULTS
A total of 10 studies involving 687 ondansetron group participants were statistically analyzed. The administration of ondansetron was associated with a statistically significant prevalence of QT prolongation in all age groups. An age-wise subgroup analysis was conducted which revealed that the prevalence of QT prolongation among participants younger than 18 years was not statistically significant, whereas it was statistically significant among participants aged 18-50 years and among patients older than 50 years.
CONCLUSIONS
The present meta-analysis provides further evidence that oral or intravenous administration of Ondansetron may lead to QT prolongation, particularly among patients older than 18 years of age.
PubMed: 37395900
DOI: 10.1186/s43044-023-00385-y -
Cureus Apr 2023Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder that affects approximately 2% of the human population. Traditional treatment of OCD includes selective... (Review)
Review
Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder that affects approximately 2% of the human population. Traditional treatment of OCD includes selective serotonin reuptake inhibitor (SSRI) or serotonin reuptake inhibitor (SRI) treatment along with cognitive behavioral therapy (CBT). Nearly 25%-30% of OCD patients do not respond to SSRIs. Glutamatergic agents are currently being studied for the treatment of OCD due to the glutamatergic pathway in the brain, related to OCD, and the role of the cortico-striato-thalamic circuit (CSTC). This review assesses the clinical effectiveness of N-methyl-D-aspartate (NMDA) antagonists, ketamine/esketamine, memantine, and amantadine, for adult patients with OCD. Inclusion criteria include human studies published within the last 15 years, with patients diagnosed with OCD, aged over 18 years, with only psychiatric comorbidities, and full-text articles. Papers that included interventions other than CBT, exposure with response prevention (ERP), and SSRI/SRI were excluded. Articles were searched for using PubMed, PubMed Central, Medical Literature Analysis and Retrieval System Online, GeorgiA LIbrary LEarning Online, EBSCO Information Services, OpenAthens, Multidisciplinary Digital Publishing Institute, and Google Scholar databases, last searched on December 2, 2022. The risk of bias was assessed using Cochrane Risk of Bias tools, the Scale for the Assessment of Narrative Review Articles (SANRA) checklist for literature reviews, and the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for quasi-experimental studies. Results were presented and synthesized by Excel spreadsheet analysis. The database search yielded 4,221 articles, which was cut down to 18 articles by inclusion/exclusion criteria, including duplications. 80% of the ketamine studies resulted in a significant reduction of obsessions and compulsions based on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), and each of the memantine and amantadine studies displayed clinical effectiveness, also. Limitations include the small number of amantadine studies and the limited availability of other NMDA receptor (NMDAR) antagonist-focused studies. This systematic review shows that ketamine is an effective drug for the treatment of non-refractory, mild to moderate OCD, and memantine and amantadine are effective augmentation agents for the treatment of mild to severe OCD.
PubMed: 37213965
DOI: 10.7759/cureus.37833 -
Indian Pediatrics Aug 2023Serotonin receptors 5-HT1B and 5-HT1D in the cerebral arteries are activated by the 5-hydroxytryptophan agonists (triptans) to relieve the discomfort associated with...
BACKGROUND
Serotonin receptors 5-HT1B and 5-HT1D in the cerebral arteries are activated by the 5-hydroxytryptophan agonists (triptans) to relieve the discomfort associated with migraines. Even though triptans are often used to treat acute migraines, there is some debate over their effectiveness.
OBJECTIVE
Our systematic review aimed to evaluate the effectiveness of triptans for acute treatment of migraine in young individuals.
METHODS
Utilizing the databases of Google Scholar, Cochrane Library, and PubMed, a literature search was conducted, and all papers published till July 2022 were included. This systematic review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. In addition to the Boolean operators AND, OR, and NOT, the following descriptive terms were also used: "Triptans," "Pediatric Migraine," "Migraine disorders," "Headache," "Children," and "Adolescent."
RESULTS
A total of 1047 studies were identified, and 25 articles were finally included in the study. 17 of them were RCTs while the remaining were non-randomized trials. Most studies recruited participants aged between 12-17 years. Among 25 studies, 7 reported sumatriptan use, 3 assessed a combination of sumatriptan and naproxen, 4 were on almotriptan, 1 on eletriptan, 6 on rizatriptan, and 4 on zolmitriptan use.
CONCLUSION
We found that rizatriptan (good tolerability profile with a dose of 5 mg) and sumatriptan (nasal spray, 10 mg and 20 mg) had higher efficiency as compared to other triptans. Regardless of type or dose, all triptans are generally well tolerated by patients, but a few adverse effects such as light-headedness (sumatriptan), nasopharyngitis, and, muscular spasms (sumatriptan/ naproxen), somnolence, and dry mouth (rizatriptan), and dizziness (zolmitriptan group) were reported with the triptans.
Topics: Adolescent; Humans; Child; Sumatriptan; Naproxen; Tryptamines; Migraine Disorders; Headache
PubMed: 37209053
DOI: No ID Found -
Advances in Clinical and Experimental... Oct 2023Psychosis is a very common feature of Alzheimer's disease (AD) that can emerge as the neurodegenerative disease progresses. The 5-hydroxytryptamine (5-HT2A) receptors... (Meta-Analysis)
Meta-Analysis
Efficacy and safety of negative allosteric modulators of 5-hydroxytryptamine 2A receptors in the treatment of Alzheimer's disease psychosis: A systematic review and meta-analysis.
BACKGROUND
Psychosis is a very common feature of Alzheimer's disease (AD) that can emerge as the neurodegenerative disease progresses. The 5-hydroxytryptamine (5-HT2A) receptors are located postsynaptically to serotonergic neurons in the frontal cortex and mediate both excitatory and inhibitory neurotransmissions. However, the effectiveness and tolerance of negative modulators of 5-HT2A receptors in Alzheimer's disease psychosis (ADP) are uncertain.
OBJECTIVES
To detect the negative modulators of the 5-HT2A receptor as a cure for ADP.
MATERIAL AND METHODS
The primary outcome indicator was the total Neuropsychiatric Inventory (NPI) score. Other prognostic indicators included Mini-Mental State Examination (MMSE), the Katz Index of Independence in Activities of Daily Living (KATZ), the discontinuation rate, and adverse events.
RESULTS
Compared to placebo, 5-HT2A inverse agonists significantly reduced the NPI total score, the KATZ and the MMSE score. The pooled odds ratio (OR) was 1.64 (95% confidence interval (95% CI): 1.01-2.65) and the heterogeneity variance was estimated at Tau2 = 0.52 with an I2 value of 90%, a χ2 value of 111.31, p = 0.04, and z-value of 2.01. The risk difference (RD) between the 5-HT2A receptor negative modulators and placebo groups was 0.12 (95% CI: 0.00-0.24) and the heterogeneity was estimated at Tau2 = 0.03, χ2 value of 127.23, degrees of freedom (df) value of 9, I2 value of 93%, z-value of 1.92, and p-value of 0.01 (<0.05).
CONCLUSION
Our results suggest that negative modulators of 5-HT2A receptors are beneficial and well-tolerated in the treatment of ADP.
Topics: Humans; Alzheimer Disease; Serotonin; Neurodegenerative Diseases; Activities of Daily Living; Drug Inverse Agonism; Receptor, Serotonin, 5-HT2A; Psychotic Disorders
PubMed: 37166012
DOI: 10.17219/acem/161159 -
Molecular Psychiatry Jul 2023Impairment of insulin action and metabolic dysregulation have traditionally been associated with schizophrenia, although the molecular basis of such association remains... (Meta-Analysis)
Meta-Analysis
Impairment of insulin action and metabolic dysregulation have traditionally been associated with schizophrenia, although the molecular basis of such association remains still elusive. The present meta-analysis aims to assess the impact of insulin action manipulations (i.e., hyperinsulinemia, hypoinsulinemia, systemic or brain insulin resistance) on glutamatergic, dopaminergic, γ-aminobutyric acid (GABA)ergic, and serotonergic pathways in the central nervous system. More than one hundred outcomes, including transcript or protein levels, kinetic parameters, and other components of the neurotransmitter pathways, were collected from cultured cells, animals, or humans, and meta-analyzed by applying a random-effects model and adopting Hedges'g to compare means. Two hundred fifteen studies met the inclusion criteria, of which 180 entered the quantitative synthesis. Significant impairments in key regulators of synaptic plasticity processes were detected as the result of insulin handlings. Specifically, protein levels of N-methyl-D-aspartate receptor (NMDAR) subunits including type 2A (NR2A) (Hedges' g = -0.95, 95%C.I. = -1.50, -0.39; p = 0.001; I = 47.46%) and 2B (NR2B) (Hedges'g = -0.69, 95%C.I. = -1.35, -0.02; p = 0.043; I = 62.09%), and Postsynaptic density protein 95 (PSD-95) (Hedges'g = -0.91, 95%C.I. = -1.51, -0.32; p = 0.003; I = 77.81%) were found reduced in insulin-resistant animal models. Moreover, insulin-resistant animals showed significantly impaired dopamine transporter activity, whereas the dopamine D2 receptor mRNA expression (Hedges'g = 3.259; 95%C.I. = 0.497, 6.020; p = 0.021; I = 90.61%) increased under insulin deficiency conditions. Insulin action modulated glutamate and GABA release, as well as several enzymes involved in GABA and serotonin synthesis. These results suggest that brain neurotransmitter systems are susceptible to insulin signaling abnormalities, resembling the discrete psychotic disorders' neurobiology and possibly contributing to the development of neurobiological hallmarks of treatment-resistant schizophrenia.
Topics: Humans; Animals; Schizophrenia; Insulin; Neurobiology; Disks Large Homolog 4 Protein; Receptors, N-Methyl-D-Aspartate; gamma-Aminobutyric Acid; Neurotransmitter Agents
PubMed: 37085712
DOI: 10.1038/s41380-023-02065-4