Chlorpyrifos exposure during neurulation: cholinergic synaptic dysfunction and cellular alterations in brain regions at adolescence and adulthood

2004 ◽  
Vol 148 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Dan Qiao ◽  
Frederic J. Seidler ◽  
Yael Abreu-Villaça ◽  
Charlotte A. Tate ◽  
Mandy M. Cousins ◽  
...  
Keyword(s):  
Brain Regions ◽  
Synaptic Dysfunction ◽  
Cellular Alterations

scholarly journals Synaptic Dysfunction in Depression: Potential Therapeutic Targets

Science ◽  
2012 ◽  
Vol 338 (6103) ◽  
pp. 68-72 ◽  
Author(s):  
Ronald S. Duman ◽  
George K. Aghajanian
Keyword(s):  
Response Times ◽  
Brain Regions ◽  
Synaptic Dysfunction ◽  
Delayed Response ◽  
Central Importance ◽  
Neuronal Synapses ◽  
Aspartate Receptor ◽  
Limited Efficacy ◽  
Basic Studies ◽  
Mood And Cognition

Basic and clinical studies demonstrate that depression is associated with reduced size of brain regions that regulate mood and cognition, including the prefrontal cortex and the hippocampus, and decreased neuronal synapses in these areas. Antidepressants can block or reverse these neuronal deficits, although typical antidepressants have limited efficacy and delayed response times of weeks to months. A notable recent discovery shows that ketamine, a N-methyl-d-aspartate receptor antagonist, produces rapid (within hours) antidepressant responses in patients who are resistant to typical antidepressants. Basic studies show that ketamine rapidly induces synaptogenesis and reverses the synaptic deficits caused by chronic stress. These findings highlight the central importance of homeostatic control of mood circuit connections and form the basis of a synaptogenic hypothesis of depression and treatment response.

scholarly journals Mutant huntingtin reduces vesicular zinc level by inhibiting the binding of Sp1 to ZnT3 promoter

2020 ◽  
Author(s):  
Li Niu ◽  
Shiming Yang ◽  
Weixi Wang ◽  
Cui-fang Ye ◽  
He Li
Keyword(s):  
Molecular Mechanisms ◽  
Early Stage ◽  
Brain Regions ◽  
Zinc Level ◽  
Significant Loss ◽  
Zinc Homeostasis ◽  
Synaptic Dysfunction ◽  
Mutant Huntingtin ◽  
Bhk Cells ◽  
The Brain

Abstract Background Synaptic dysfunction caused by mutant huntingtin greatly contributes to Huntington’s disease (HD) pathogenesis. HD patients show cognitive impairment as well as uncontrolled movements. Vesicular zinc is closely linked to modulating synaptic transmission and maintaining cognitive ability. However, whether does mutant huntingtin affect zinc homeostasis in the brain or not? This will be of great significance for further revealing the pathogenesis of HD. Methods N171-HD82Q transgenic mice and cultured BHK cells expressing N-terminal mutant huntingtin fragment containing 160 glutamines (160Q BHK cells) were used to investigate the effect of mutant huntingtin on zinc homeostasis and its molecular mechanisms. Results Herein, we have demonstrated that the density of synaptic vesicular zinc decreases in the cortex, striatum and hippocampus of N171-82Q mice. Given that vesicular zinc concentration depends on the abundance of zinc transporter 3 (ZnT3) on the membrane of synaptic vesicles, ZnT3 expression is detected in the brain of N171-82Q mice and 160Q BHK cells. Mutant huntingtin leads to a dramatical decrease in ZnT3 mRNA and protein levels in the three brain regions of these mice aged from 14 to 20 weeks. Significantly, Sp1 activates ZnT3 transcription via its binding to the GC boxes in ZnT3 promoter. Nevertheless, mutant huntingtin inhibits the binding of Sp1 to the promoter of ZnT3 gene and down-regulates ZnT3 expression. Furthermore, the overexpression of Sp1 ameliorates inhibition of ZnT3 gene transcription by mutant huntingtin. Conclusions Collectively, this first study to reveal a significant loss of synaptic vesicular zinc and ZnT3 expression caused by mutant huntingtin in the early stage of HD. Our findings have revealed the molecular mechanism underlying this change. Mutant huntingtin inhibits the binding of Sp1 to ZnT3 gene promoter to reduce ZnT3 expression. The imbalance of vesicular zinc homeostasis may be closely associated with synaptic dysfunction and cognitive deficits in HD. This work sheds novel mechanistic insights into the pathogenesis of HD and promises a potential therapeutic strategy for HD.

Synaptic organization of the gustatory NST

1994 ◽  
Vol 52 ◽  
pp. 150-151
Author(s):  
M. C. Whitehead
Keyword(s):  
Central Nervous System ◽  
Dendritic Spines ◽  
Fundamental Problem ◽  
Cell Types ◽  
Brain Regions ◽  
Excitatory Synapses ◽  
Solitary Tract ◽  
Synaptic Organization ◽  
Synaptic Junctions ◽  
Afferent Terminals

A fundamental problem in taste research is to determine how gustatory signals are processed and disseminated in the mammalian central nervous system. An important first step toward understanding information processing is the identification of cell types in the nucleus of the solitary tract (NST) and their synaptic relationships with oral primary afferent terminals. Facial and glossopharyngeal (LIX) terminals in the hamster were labelled with HRP, examined with EM, and characterized as containing moderate concentrations of medium-sized round vesicles, and engaging in asymmetrical synaptic junctions. Ultrastructurally the endings resemble excitatory synapses in other brain regions.Labelled facial afferent endings in the RC subdivision synapse almost exclusively with distal dendrites and dendritic spines of NST cells. Most synaptic relationships between the facial synapses and the dendrites are simple. However, 40% of facial endings engage in complex synaptic relationships within glomeruli containing unlabelled axon endings particularly ones termed "SP" endings. SP endings are densely packed with small, pleomorphic vesicles and synapse with both the facial endings and their postsynaptic dendrites by means of nearly symmetrical junctions.

Musical Anhedonia

2020 ◽  
Vol 31 (2) ◽  
pp. 62-68
Author(s):  
Sara E. Holm ◽  
Alexander Schmidt ◽  
Christoph J. Ploner
Keyword(s):  
Quality Of Life ◽  
Nucleus Accumbens ◽  
Brain Damage ◽  
Parietal Cortex ◽  
Neurological Disorders ◽  
Brain Regions ◽  
Precise Information ◽  
Exact Localization ◽  
High Prevalence

Abstract. Some people, although they are perfectly healthy and happy, cannot enjoy music. These individuals have musical anhedonia, a condition which can be congenital or may occur after focal brain damage. To date, only a few cases of acquired musical anhedonia have been reported in the literature with lesions of the temporo-parietal cortex being particularly important. Even less literature exists on congenital musical anhedonia, in which impaired connectivity of temporal brain regions with the Nucleus accumbens is implicated. Nonetheless, there is no precise information on the prevalence, causes or exact localization of both congenital and acquired musical anhedonia. However, the frequent involvement of temporo-parietal brain regions in neurological disorders such as stroke suggest the possibility of a high prevalence of this disorder, which leads to a considerable reduction in the quality of life.

Serotonergic Genes and Suicidality

Crisis ◽  
2001 ◽  
Vol 22 (2) ◽  
pp. 54-60 ◽  
Author(s):  
Lisheng Du ◽  
Gabor Faludi ◽  
Miklos Palkovits ◽  
David Bakish ◽  
Pavel D. Hrdina
Keyword(s):  
Suicidal Ideation ◽  
Suicidal Behavior ◽  
Tryptophan Hydroxylase ◽  
Association Studies ◽  
Receptor Gene ◽  
Brain Regions ◽  
Depressive Illness ◽  
Control Group ◽  
Serotonergic Activity ◽  
Completed Suicide

Summary: Several lines of evidence indicate that abnormalities in the functioning of the central serotonergic system are involved in the pathogenesis of depressive illness and suicidal behavior. Studies have shown that the number of brain and platelet serotonin transporter binding sites are reduced in patients with depression and in suicide victims, and that the density of 5-HT2A receptors is increased in brain regions of depressed in suicide victims and in platelets of depressed suicidal patients. Genes that code for proteins, such as tryptophan hydroxylase, 5-HT transporter, and 5-HT2A receptor, involved in regulating serotonergic neurotransmission, have thus been major candidate genes for association studies of suicide and suicidal behavior. Recent studies by our group and by others have shown that genetic variations in the serotonin-system-related genes might be associated with suicidal ideation and completed suicide. We have shown that the 102 C allele in 5-HT2A receptor gene was significantly associated with suicidal ideation (χ2 = 8.5, p < .005) in depressed patients. Patients with a 102 C/C genotype had a significantly higher mean HAMD item #3 score (indication of suicidal ideation) than T/C or T/T genotype patients. Our results suggest that the 102T/C polymorphism in 5-HT2A receptor gene is primarily associated with suicidal ideation in patients with major depression and not with depression itself. We also found that the 5-HT transporter gene S/L polymorphism was significantly associated with completed suicide. The frequency of the L/L genotype in depressed suicide victims was almost double of that found in control group (48.6% vs. 26.2%). The odds ratio for the L allele was 2.1 (95% CI 1.2-3.7). The association between polymorphism in serotonergic genes and suicidality supports the hypothesis that genetic factors can modulate suicide risk by influencing serotonergic activity.

Inefficient Encoding as an Explanation for Age-Related Deficits in Recollection-Based Processing

2014 ◽  
Vol 28 (3) ◽  
pp. 148-161 ◽  
Author(s):  
David Friedman ◽  
Ray Johnson
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Cognitive Processes ◽  
Brain Activity ◽  
Memory Performance ◽  
Brain Regions ◽  
Semantic Retrieval ◽  
Age Related ◽  
The Face ◽  
Episodic Memories

A cardinal feature of aging is a decline in episodic memory (EM). Nevertheless, there is evidence that some older adults may be able to “compensate” for failures in recollection-based processing by recruiting brain regions and cognitive processes not normally recruited by the young. We review the evidence suggesting that age-related declines in EM performance and recollection-related brain activity (left-parietal EM effect; LPEM) are due to altered processing at encoding. We describe results from our laboratory on differences in encoding- and retrieval-related activity between young and older adults. We then show that, relative to the young, in older adults brain activity at encoding is reduced over a brain region believed to be crucial for successful semantic elaboration in a 400–1,400-ms interval (left inferior prefrontal cortex, LIPFC; Johnson, Nessler, & Friedman, 2013 ; Nessler, Friedman, Johnson, & Bersick, 2007 ; Nessler, Johnson, Bersick, & Friedman, 2006 ). This reduced brain activity is associated with diminished subsequent recognition-memory performance and the LPEM at retrieval. We provide evidence for this premise by demonstrating that disrupting encoding-related processes during this 400–1,400-ms interval in young adults affords causal support for the hypothesis that the reduction over LIPFC during encoding produces the hallmarks of an age-related EM deficit: normal semantic retrieval at encoding, reduced subsequent episodic recognition accuracy, free recall, and the LPEM. Finally, we show that the reduced LPEM in young adults is associated with “additional” brain activity over similar brain areas as those activated when older adults show deficient retrieval. Hence, rather than supporting the compensation hypothesis, these data are more consistent with the scaffolding hypothesis, in which the recruitment of additional cognitive processes is an adaptive response across the life span in the face of momentary increases in task demand due to poorly-encoded episodic memories.

Inflammational Animal Models for Schizophrenia

2015 ◽  
Vol 223 (3) ◽  
pp. 157-164 ◽  
Author(s):  
Georg Juckel
Keyword(s):  
Animal Model ◽  
Animal Models ◽  
Immune Activation ◽  
Microglial Activation ◽  
Treatment Options ◽  
Early Adulthood ◽  
Brain Regions ◽  
Synaptic Connections ◽  
Preventive Interventions ◽  
Immunological System

Abstract. Inflammational-immunological processes within the pathophysiology of schizophrenia seem to play an important role. Early signals of neurobiological changes in the embryonal phase of brain in later patients with schizophrenia might lead to activation of the immunological system, for example, of cytokines and microglial cells. Microglia then induces – via the neurotoxic activities of these cells as an overreaction – a rarification of synaptic connections in frontal and temporal brain regions, that is, reduction of the neuropil. Promising inflammational animal models for schizophrenia with high validity can be used today to mimic behavioral as well as neurobiological findings in patients, for example, the well-known neurochemical alterations of dopaminergic, glutamatergic, serotonergic, and other neurotransmitter systems. Also the microglial activation can be modeled well within one of this models, that is, the inflammational PolyI:C animal model of schizophrenia, showing a time peak in late adolescence/early adulthood. The exact mechanism, by which activated microglia cells then triggers further neurodegeneration, must now be investigated in broader detail. Thus, these animal models can be used to understand the pathophysiology of schizophrenia better especially concerning the interaction of immune activation, inflammation, and neurodegeneration. This could also lead to the development of anti-inflammational treatment options and of preventive interventions.

Sign in / Sign up

Export Citation Format

Share Document