How dopamine leads to hallucinations

Neuroprotection Role of Vitamin C by Upregulating Glutamate Transporter-1 in Auditory Cortex of Noise-Induced Tinnitus Animal Model

Vitamin C (Vc) plays a pivotal role in a series of pathological processes, such as tumors, immune diseases, and neurological disorders. However, its therapeutic potential for tinnitus management remains unclear. In this study, we find that Vc relieves tinnitus in noise-exposed rats. In the 7-day therapy groups, spontaneous firing rate (SFR) increases from 1.17 ± 0.10 Hz to 1.77 ± 0.15 Hz after noise exposure. Vc effectively reduces the elevated SFR to 0.99 ± 0.07 and 0.55 ± 0.05 Hz at different doses. The glutamate level in auditory cortex of noise-exposed rats (3.78 ± 0.42 μM) increases relative to that in the control group (1.34 ± 0.22 μM). High doses of Vc (500 mg/kg/day) effectively reduce the elevated glutamate levels (1.49 ± 0.28 μM). Mechanistic studies show that the expression of glutamate transporter 1 (GLT-1) is impaired following noise exposure and that Vc treatment effectively restores GLT-1 expression in the auditory cortex. Meanwhile, the GLT-1 inhibitor, dl-threo-beta-benzyloxyaspartic acid (dl-TBOA), invalidates the protection role of Vc. Our finding shows that Vc substantially enhances glutamate clearance by upregulating GLT-1 and consequently alleviates noise-induced tinnitus. This study provides valuable insight into a novel biological target for the development of therapeutic interventions that may prevent the onset of tinnitus.

Aberrant resting-state functional connectivity of the globus pallidus interna in first-episode schizophrenia

BACKGROUND

The striatal-pallidal pathway plays an important role in cognitive control and modulation of behaviors. Globus pallidus interna (GPi), as a primary output structure, is crucial in modulating excitation and inhibition. Studies of GPi in psychiatric illnesses are lacking given the technical challenges of examining this small and functionally diverse subcortical structure.

METHODS

71 medication-naïve first episode schizophrenia (FES) participants and 73 healthy controls (HC) were recruited at the Shanghai Mental Health Center. Clinical symptoms and imaging data were collected at baseline and, in a subset of patients, 8 weeks after initiating treatment. Resting-state functional connectivity of sub-regions of the GP were assessed using a novel mask that combines two atlases to create 8 ROIs in the GP.

RESULTS

Baseline imaging data from 63 FES patients and 55 HC met quality standards and were analyzed. FES patients exhibited less negative connectivity and increased positive connectivity between the right anterior GPi and several cortical and subcortical areas at baseline compared to HC (PFWE < 0.05). Positive functional connectivity between the right anterior GPi and several brain areas, including the right dorsal anterior cingulate gyrus, was associated with severity of positive symptoms (PFWE < 0.05) and predicted treatment response after 8 weeks (n = 28, adjusted R2 = 0.486, p < 0.001).

CONCLUSIONS

Our results implicate striatal-pallidal-thalamic pathways in antipsychotic efficacy. If replicated, these findings may reflect failure of neurodevelopmental processes in adolescence and early adulthood that decrease functional connectivity as an index of failure of the limbic/associative GPi to appropriately inhibit irrelevant signals in psychosis.

Multicolor colorimetric detection of dopamine based on iodide-responsive copper-gold nanoparticles

Dopamine (DA) is one of the most essential catecholamine neurotransmitters in the human body. A rapid colorimetric detection method for DA in urine and serum was established in this work using unmodified iodide-responsive copper-gold nanoparticles (Cu-Au NPs). The detection method provides a rapid response with color variability within 15 min at room temperature. In addition, the colorimetric probe has elevated stability, excellent selectivity and resistance to interference.

Gene, cell type, and drug prioritization analysis suggest genetic basis for the utility of diuretics in treating Alzheimer disease

We introduce a user-friendly tool for risk gene, cell type, and drug prioritization for complex traits: GCDPipe. It uses gene-level GWAS-derived data and gene expression data to train a model for the identification of disease risk genes and relevant cell types. Gene prioritization information is then coupled with known drug target data to search for applicable drug agents based on their estimated functional effects on the identified risk genes. We illustrate the utility of our approach in different settings: identification of the cell types, implicated in disease pathogenesis, was tested in inflammatory bowel disease (IBD) and Alzheimer disease (AD); gene target and drug prioritization was tested in IBD and schizophrenia. The analysis of phenotypes with known disease-affected cell types and/or existing drug candidates shows that GCDPipe is an effective tool to unify genetic risk factors with cellular context and known drug targets. Next, analysis of the AD data with GCDPipe suggested that gene targets of diuretics, as an Anatomical Therapeutic Chemical drug subgroup, are significantly enriched among the genes prioritized by GCDPipe, indicating their possible effect on the course of the disease.