scholarly journals The Entorhinal Cortex and Adult Neurogenesis in Major Depression

2021 ◽  
Vol 22 (21) ◽  
pp. 11725
Author(s):  
Il Bin Kim ◽  
Seon-Cheol Park
Keyword(s):  
Entorhinal Cortex ◽  
Adult Neurogenesis ◽  
Potential Role ◽  
Neural Circuitry ◽  
Hippocampal Neurogenesis ◽  
Dependent Manner ◽  
Hippocampal Function ◽  
Comprehensive Understanding ◽  
Activity Dependent

Depression is characterized by impairments in adult neurogenesis. Reduced hippocampal function, which is suggestive of neurogenesis impairments, is associated with depression-related phenotypes. As adult neurogenesis operates in an activity-dependent manner, disruption of hippocampal neurogenesis in depression may be a consequence of neural circuitry impairments. In particular, the entorhinal cortex is known to have a regulatory effect on the neural circuitry related to hippocampal function and adult neurogenesis. However, a comprehensive understanding of how disruption of the neural circuitry can lead to neurogenesis impairments in depression remains unclear with respect to the regulatory role of the entorhinal cortex. This review highlights recent findings suggesting neural circuitry-regulated neurogenesis, with a focus on the potential role of the entorhinal cortex in hippocampal neurogenesis in depression-related cognitive and emotional phenotypes. Taken together, these findings may provide a better understanding of the entorhinal cortex-regulated hippocampal neurogenesis model of depression.

scholarly journals Neural Circuitry–Neurogenesis Coupling Model of Depression

2021 ◽  
Vol 22 (5) ◽  
pp. 2468
Author(s):  
Il Bin Kim ◽  
Seon-Cheol Park
Keyword(s):  
Entorhinal Cortex ◽  
Coupling Model ◽  
Neural Circuitry ◽  
Hippocampal Neurogenesis ◽  
Pattern Separation ◽  
Dependent Process ◽  
Hippocampal Activity ◽  
Mechanistic Understanding ◽  
Activity Dependent ◽  
Memory Pattern

Depression is characterized by the disruption of both neural circuitry and neurogenesis. Defects in hippocampal activity and volume, indicative of reduced neurogenesis, are associated with depression-related behaviors in both humans and animals. Neurogenesis in adulthood is considered an activity-dependent process; therefore, hippocampal neurogenesis defects in depression can be a result of defective neural circuitry activity. However, the mechanistic understanding of how defective neural circuitry can induce neurogenesis defects in depression remains unclear. This review highlights the current findings supporting the neural circuitry-regulated neurogenesis, especially focusing on hippocampal neurogenesis regulated by the entorhinal cortex, with regard to memory, pattern separation, and mood. Taken together, these findings may pave the way for future progress in neural circuitry–neurogenesis coupling studies of depression.

A Hypothesis About the Role of Adult Neurogenesis in Hippocampal Function

Physiology ◽  
2004 ◽  
Vol 19 (5) ◽  
pp. 253-261 ◽  
Author(s):  
Alejandro F. Schinder ◽  
Fred H. Gage
Keyword(s):  
Adult Neurogenesis ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Hippocampal Function ◽  
Hippocampal Plasticity ◽  
Functional Relevance ◽  
And Function ◽  
Precise Role

The functional relevance of adult hippocampal neurogenesis has long been a matter of intense experimentation and debate, but the precise role of new neurons has not been sufficiently elaborated. Here we propose a hypothesis in which specific features of newly generated neurons contribute to hippocampal plasticity and function and discuss the most recent and relevant findings in the context of the proposed hypothesis.

scholarly journals The action of α-adrenergic agonists on plasma-membrane calcium fluxes in perfused rat liver

1984 ◽  
Vol 220 (1) ◽  
pp. 43-50 ◽  
Author(s):  
P H Reinhart ◽  
W M Taylor ◽  
F L Bygrave
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Potential Role ◽  
Dependent Manner ◽  
Perfused Rat Liver ◽  
Adrenergic Agonists ◽  
Mediated Effects ◽  
Alpha Agonist ◽  
Alpha Adrenergic Agonist

The effect of alpha-adrenergic agonists on Ca2+ fluxes was examined in the perfused rat liver by using a combination of Ca2+-electrode and 45Ca2+-uptake techniques. We showed that net Ca2+ fluxes can be described by the activities of separate Ca2+-uptake and Ca2+-efflux components, and that alpha-adrenergic agonists modulate the activity of both components in a time-dependent manner. Under resting conditions, Ca2+-uptake and -efflux activities are balanced, resulting in Ca2+ cycling across the plasma membrane. The alpha-adrenergic agonists vasopressin and angiotensin, but not glucagon, stimulate the rate of both Ca2+ efflux and Ca2+ uptake. During the first 2-3 min of alpha-agonist administration the effect on the efflux component is the greater, the net effect being efflux of Ca2+ from the cell. After 3-4 min of phenylephrine treatment, net Ca2+ movements are essentially complete, however, the rate of Ca2+ cycling is significantly increased. After removal of the alpha-agonist a large stimulation of the rate of Ca2+ uptake leads to the net accumulation of Ca2+ by the cell. The potential role of these Ca2+ flux changes in the expression of alpha-adrenergic-agonist-mediated effects is discussed.

scholarly journals Quorum-sensing regulation in rhizobia and its role in symbiotic interactions with legumes

2007 ◽  
Vol 362 (1483) ◽  
pp. 1149-1163 ◽  
Author(s):  
Maria Sanchez-Contreras ◽  
Wolfgang D Bauer ◽  
Mengsheng Gao ◽  
Jayne B Robinson ◽  
J Allan Downie
Keyword(s):  
Quorum Sensing ◽  
Potential Role ◽  
Active Role ◽  
Dependent Manner ◽  
Homoserine Lactones ◽  
Signalling Molecules ◽  
Sensing Systems ◽  
Symbiotic Interactions ◽  
Regulatory Systems

Legume-nodulating bacteria (rhizobia) usually produce N -acyl homoserine lactones, which regulate the induction of gene expression in a quorum-sensing (or population-density)-dependent manner. There is significant diversity in the types of quorum-sensing regulatory systems that are present in different rhizobia and no two independent isolates worked on in detail have the same complement of quorum-sensing genes. The genes regulated by quorum sensing appear to be rather diverse and many are associated with adaptive aspects of physiology that are probably important in the rhizosphere. It is evident that some aspects of rhizobial physiology related to the interaction between rhizobia and legumes are influenced by quorum sensing. However, it also appears that the legumes play an active role, both in terms of interfering with the rhizobial quorum-sensing systems and responding to the signalling molecules made by the bacteria. In this article, we review the diversity of quorum-sensing regulation in rhizobia and the potential role of legumes in influencing and responding to this signalling system.

scholarly journals Reproduction-Associated Hormones and Adult Hippocampal Neurogenesis

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Lily Wan ◽  
Rou-Jie Huang ◽  
Zhao-Hui Luo ◽  
Jiao-e Gong ◽  
Aihua Pan ◽  
...  
Keyword(s):  
Functional Significance ◽  
Potential Role ◽  
Brain Plasticity ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Pregnancy And Postpartum

The levels of reproduction-associated hormones in females, such as estrogen, progesterone, prolactin, and oxytocin, change dramatically during pregnancy and postpartum. Reproduction-associated hormones can affect adult hippocampal neurogenesis (AHN), thereby regulating mothers' behavior after delivery. In this review, we first briefly introduce the overall functional significance of AHN and the methods commonly used to explore this front. Then, we attempt to reconcile the changes of reproduction-associated hormones during pregnancy. We further update the findings on how reproduction-related hormones influence adult hippocampal neurogenesis. This review is aimed at emphasizing a potential role of AHN in reproduction-related brain plasticity and its neurobiological relevance to motherhood behavior.

scholarly journals A role for LSH in facilitating DNA methylation by DNMT1 through enhancing UHRF1 chromatin association

2020 ◽  
Vol 48 (21) ◽  
pp. 12116-12134
Author(s):  
Mengmeng Han ◽  
Jialun Li ◽  
Yaqiang Cao ◽  
Yuanyong Huang ◽  
Wen Li ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Replication Fork ◽  
De Novo ◽  
Embryonic Stem ◽  
Dna Helicase ◽  
Dependent Manner ◽  
Essential Factor ◽  
Activity Dependent ◽  
Insight Into

Abstract LSH, a SNF2 family DNA helicase, is a key regulator of DNA methylation in mammals. How LSH facilitates DNA methylation is not well defined. While previous studies with mouse embryonic stem cells (mESc) and fibroblasts (MEFs) derived from Lsh knockout mice have revealed a role of Lsh in de novo DNA methylation by Dnmt3a/3b, here we report that LSH contributes to DNA methylation in various cell lines primarily by promoting DNA methylation by DNMT1. We show that loss of LSH has a much bigger effect in DNA methylation than loss of DNMT3A and DNMT3B. Mechanistically, we demonstrate that LSH interacts with UHRF1 but not DNMT1 and facilitates UHRF1 chromatin association and UHRF1-catalyzed histone H3 ubiquitination in an ATPase activity-dependent manner, which in turn promotes DNMT1 recruitment to replication fork and DNA methylation. Notably, UHRF1 also enhances LSH association with the replication fork. Thus, our study identifies LSH as an essential factor for DNA methylation by DNMT1 and provides novel insight into how a feed-forward loop between LSH and UHRF1 facilitates DNMT1-mediated maintenance of DNA methylation in chromatin.

scholarly journals Secretory phospholipases A2 induce neurite outgrowth in PC12 cells

2003 ◽  
Vol 376 (3) ◽  
pp. 655-666 ◽  
Author(s):  
Satoru NAKASHIMA ◽  
Yutaka IKENO ◽  
Tatsuya YOKOYAMA ◽  
Masakazu KUWANA ◽  
Angelo BOLCHI ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Streptomyces Coelicolor ◽  
Dependent Manner ◽  
Group V ◽  
Phospholipases A2 ◽  
Fatty Acid Release ◽  
Activity Dependent

sPLA2s (secretory phospholipases A2) belong to a broad and structurally diverse family of enzymes that hydrolyse the sn-2 ester bond of glycerophospholipids. We previously showed that a secreted fungal 15 kDa protein, named p15, as well as its orthologue from Streptomyces coelicolor (named Scp15) induce neurite outgrowth in PC12 cells at nanomolar concentrations. We report here that both p15 and Scp15 are members of a newly identified group of fungal/bacterial sPLA2s. The phospholipid-hydrolysing activity of p15 is absolutely required for neurite outgrowth induction. Mutants with a reduced PLA2 activity exhibited a comparable reduction in neurite-inducing activity, and the ability to induce neurites closely matched the capacity of various p15 forms to promote fatty acid release from live PC12 cells. A structurally divergent member of the sPLA2 family, bee venom sPLA2, also induced neurites in a phospholipase activity-dependent manner, and the same effect was elicited by mouse group V and X sPLA2s, but not by group IB and IIA sPLA2s. Lysophosphatidylcholine, but not other lysophospholipids, nor arachidonic acid, elicited neurite outgrowth in an L-type Ca2+ channel activity-dependent manner. In addition, p15-induced neuritogenesis was unaffected by various inhibitors that block arachidonic acid conversion into bioactive eicosanoids. Altogether, these results delineate a novel, Ca2+- and lysophosphatidylcholine-dependent neurotrophin-like role of sPLA2s in the nervous system.

PROBABILITY OF ENTRAINMENT, SYNAPTIC MODIFICATION AND ENTRAINED PHASE ARE PHASE-DEPENDENT IN STDP

2010 ◽  
Vol 18 (02) ◽  
pp. 479-493
Author(s):  
GANG ZHAO
Keyword(s):  
Neural Coding ◽  
Numerical Study ◽  
Spike Timing ◽  
Dependent Manner ◽  
Initial State ◽  
Pacemaker Neurons ◽  
Strongly Nonlinear ◽  
Synaptic Modification ◽  
Activity Dependent

Synaptic conductance can be modified in an activity dependent manner, in which the temporal relationship between pre- and post-synaptic spikes plays a major role. This spike timing dependent plasticity (STDP) has profound implications in neural coding, computation and functionality. Because the STDP learning curve is strongly nonlinear, initial state may have great impacts on the eventual state of the system. However, although this feature is intuitively clear, it has not been explored in detail before. This paper presents a preliminary numerical study in this direction. In a model of two pacemaker neurons and a synapse undergoing STDP, it is found that the probability of entrainment, direction of synaptic modification and entrained phase are all influenced by the initial relative phase. Based on these findings, it is reasonable to propose that the initial-state sensitive feature of STDP may contribute to its role of selective response in oscillatory neural networks.

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