Hippocampus is more vulnerable to neural damages induced by repeated sevoflurane exposure in the second trimester than other brain areas

2020 ◽  
Vol 52 (8) ◽  
pp. 864-874
Author(s):  
Bing Chen ◽  
Yanjun Liu ◽  
Yirong Cai ◽  
Dan Tang ◽  
Saihong Xu ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Brain Regions ◽  
Sensitive Period ◽  
Second Trimester ◽  
Brain Areas ◽  
Axon Development ◽  
The Central Nervous System ◽  
New Perspective ◽  
Anesthetic Exposure ◽  
The Brain

Abstract During the rapidly developing and sensitive period of the central nervous system (CNS), a harmful stimulus may have serious consequences. The effect of anesthetic exposure on the development of the offspring’s CNS during pregnancy is still unclear and has been widely concerned. In the present study, we compared the susceptibility of the hippocampus with those of other brain regions in offsprings when the mother mice were exposed to repeated sevoflurane. We found that other than affecting motor sensation, emotion, or social behavior of offspring mice, repeated sevoflurane exposure induced significant memory deficiency. Compared with other brain regions, the hippocampus, which is the key component of the brain serving for learning and memory, was more vulnerable to repeated sevoflurane exposure. We also found that repeated sevoflurane exposure to mother mice could inhibit the axon development of hippocampal neurons. We also predicted that N6-methyladenosine modification of mRNA might play an essential role in the vulnerability of the hippocampus to sevoflurane, while the underlying cellular mechanism needs to be explored in the future. Our study may provide a new perspective for studying the mechanism of hippocampus-specific injury induced by sevoflurane exposure.

Exposure to 835 MHz radiofrequency electromagnetic field induces autophagy in hippocampus but not in brain stem of mice

2017 ◽  
Vol 34 (1) ◽  
pp. 23-35 ◽  
Author(s):  
Ju Hwan Kim ◽  
Da-Hyeon Yu ◽  
Hyo-Jeong Kim ◽  
Yang Hoon Huh ◽  
Seong-Wan Cho ◽  
...  
Keyword(s):  
Brain Stem ◽  
Mobile Phones ◽  
Hippocampal Neurons ◽  
Brain Regions ◽  
Pcr Analysis ◽  
Limited Information ◽  
The Central Nervous System ◽  
Neuronal Functions ◽  
Adaptation Processes ◽  
The Brain

The exploding popularity of mobile phones and their close proximity to the brain when in use has raised public concern regarding possible adverse effects from exposure to radiofrequency electromagnetic fields (RF-EMF) on the central nervous system. Numerous studies have suggested that RF-EMF emitted by mobile phones can influence neuronal functions in the brain. Currently, there is still very limited information on what biological mechanisms influence neuronal cells of the brain. In the present study, we explored whether autophagy is triggered in the hippocampus or brain stem after RF-EMF exposure. C57BL/6 mice were exposed to 835 MHz RF-EMF with specific absorption rates (SAR) of 4.0 W/kg for 12 weeks; afterward, the hippocampus and brain stem of mice were dissected and analyzed. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis demonstrated that several autophagic genes, which play key roles in autophagy regulation, were significantly upregulated only in the hippocampus and not in the brain stem. Expression levels of LC3B-II protein and p62, crucial autophagic regulatory proteins, were significantly changed only in the hippocampus. In parallel, transmission electron microscopy (TEM) revealed an increase in the number of autophagosomes and autolysosomes in the hippocampal neurons of RF-EMF-exposed mice. The present study revealed that autophagy was induced in the hippocampus, not in the brain stem, in 835 MHz RF-EMF with an SAR of 4.0 W/kg for 12 weeks. These results could suggest that among the various adaptation processes to the RF-EMF exposure environment, autophagic degradation is one possible mechanism in specific brain regions.

scholarly journals Limbic Expression of mRNA Coding for Chemoreceptors in Human Brain—Lessons from Brain Atlases

2021 ◽  
Vol 22 (13) ◽  
pp. 6858
Author(s):  
Fanny Gaudel ◽  
Gaëlle Guiraudie-Capraz ◽  
François Féron
Keyword(s):  
G Proteins ◽  
The Body ◽  
Trace Amines ◽  
Chemical Senses ◽  
Brain Areas ◽  
Genes Encoding ◽  
The Central Nervous System ◽  
Human Brains ◽  
The Brain ◽  
Brain Atlases

Animals strongly rely on chemical senses to uncover the outside world and adjust their behaviour. Chemical signals are perceived by facial sensitive chemosensors that can be clustered into three families, namely the gustatory (TASR), olfactory (OR, TAAR) and pheromonal (VNR, FPR) receptors. Over recent decades, chemoreceptors were identified in non-facial parts of the body, including the brain. In order to map chemoreceptors within the encephalon, we performed a study based on four brain atlases. The transcript expression of selected members of the three chemoreceptor families and their canonical partners was analysed in major areas of healthy and demented human brains. Genes encoding all studied chemoreceptors are transcribed in the central nervous system, particularly in the limbic system. RNA of their canonical transduction partners (G proteins, ion channels) are also observed in all studied brain areas, reinforcing the suggestion that cerebral chemoreceptors are functional. In addition, we noticed that: (i) bitterness-associated receptors display an enriched expression, (ii) the brain is equipped to sense trace amines and pheromonal cues and (iii) chemoreceptor RNA expression varies with age, but not dementia or brain trauma. Extensive studies are now required to further understand how the brain makes sense of endogenous chemicals.

Differential recovery of acetylcholinesterase in guinea pig muscle and brain regions after soman treatment

1998 ◽  
Vol 17 (3) ◽  
pp. 157-162 ◽  
Author(s):  
Maxine C Lintern ◽  
Janet R Wetherell ◽  
Margaret E Smith
Keyword(s):  
Enzyme Activity ◽  
Time Course ◽  
Brain Regions ◽  
Similar Rate ◽  
Molecular Forms ◽  
Similar Degree ◽  
Brain Areas ◽  
Pig Muscle ◽  
Rate Of Recovery ◽  
The Brain

1 In brain areas of untreated guinea-pigs the highest activity of acetylcholinesterase was seen in the striatum and cerebellum, followed by the midbrain, medulla-pons and cortex, and the lowest in the hippocampus. The activity in diaphragm was sevenfold lower than in the hippocampus. 2 At 1 h after soman (27 mg/kg) administration the activity of the enzyme was dramatically reduced in all tissues studied. In muscle the three major molecular forms (A12, G4 and G1) showed a similar degree of inhibition and a similar rate of recovery and the activity had returned to normal by 7 days. 3 In the brain soman inhibited the G4 form more than the G1 form. The hippocampus, cortex and midbrain showed the greatest reductions in enzyme activity. At 7 days the activity in the cortex, medulla pons and striatum had recovered but in the hippocampus, midbrain and cerebellum it was still inhibited. 4 Thus the effects of soman administration varied in severity and time course in the different tissues studied. However the enzyme activity was still reduced in all tissues at 24 h when the overt signs of poisoning had disappeared.

scholarly journals Leptin Controls Glutamatergic Synaptogenesis and NMDA-Receptor Trafficking via Fyn Kinase Regulation of NR2B

Endocrinology ◽  
2019 ◽  
Vol 161 (2) ◽  
Author(s):  
Tyler Bland ◽  
Mingyan Zhu ◽  
Crystal Dillon ◽  
Gulcan Semra Sahin ◽  
Jose Luis Rodriguez-Llamas ◽  
...  
Keyword(s):  
Nmda Receptor ◽  
Hippocampal Neurons ◽  
Leptin Receptor ◽  
Kinase Inhibitor ◽  
Phosphorylation Site ◽  
Surface Expression ◽  
Brain Regions ◽  
Dominant Negative ◽  
Nmda Receptor Function ◽  
The Central Nervous System

Abstract Activation of the leptin receptor, LepRb, by the adipocytokine/neurotrophic factor leptin in the central nervous system has procognitive and antidepressive effects. Leptin has been shown to increase glutamatergic synaptogenesis in multiple brain regions. In contrast, mice that have a mutation in the LepRb gene show abnormal synapse development in the hippocampus as well as deficits in cognition and increased depressive-like symptoms. Leptin increases glutamatergic synaptogenesis, in part, through enhancement of N-methyl-D-aspartic acid (NMDA) receptor function; yet the underlying signaling pathway is not known. In this study, we examine how leptin regulates surface expression of NR2B-containing NMDA receptors in hippocampal neurons. Leptin stimulation increases NR2BY1472 phosphorylation, which is inhibited by the Src family kinase inhibitor, PP1. Moreover, we show that Fyn, a member of the Src family kinases, is required for leptin-stimulated NR2BY1472 phosphorylation. Furthermore, inhibiting Y1472 phosphorylation with either a dominant negative Fyn mutant or an NR2B mutant that lacks the phosphorylation site (NR2BY1472F) blocks leptin-stimulated synaptogenesis. Additionally, we show that LepRb forms a complex with NR2B and Fyn. Taken together, these findings expand our knowledge of the LepRb interactome and the mechanisms by which leptin stimulates glutamatergic synaptogenesis in the developing hippocampus. Comprehending these mechanisms is key for understanding dendritic spine development and synaptogenesis, alterations of which are associated with many neurological disorders.

scholarly journals Recent developments in cognitive fMRI for temporal lobe epilepsy

2019 ◽  
Vol 33 (1) ◽  
pp. 30-36 ◽  
Author(s):  
Victor Schmidbauer ◽  
Silvia Bonelli
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Visual Memory ◽  
Imaging Modality ◽  
Memory Function ◽  
Brain Regions ◽  
Epileptogenic Zone ◽  
Brain Areas ◽  
Recent Developments ◽  
The Brain

AbstractEpilepsy is frequently accompanied by severe cognitive side effects. Temporal lobe epilepsy (TLE), and even successful surgical treatment, may affect cognitive function, in particular language as well as verbal and visual memory function. Epilepsy arising from the temporal lobe can be controlled surgically in up to 70% of patients. The goals of epilepsy surgery are to remove the brain areas generating the seizures without causing or aggravating neuropsychological deficits. This requires accurate localization of the brain areas generating the seizures (“epileptogenic zone”) and the areas responsible for motor and cognitive functions, such as language and memory (“essential brain regions”) during presurgical evaluation. In the past decades, functional magnetic resonance imaging (fMRI) has been increasingly used to noninvasively lateralize and localize not only primary motor and somatosensory areas, but also brain areas that are involved in everyday language and memory processes. The imaging modality also shows potential for predicting the effects of temporal lobe resection on language and memory function. Together with other MRI modalities, cognitive fMRI is a promising tool to improve surgical strategies tailored to individual patients with regard to functional outcome, by virtue of definition of epileptic cerebral areas that need to be resected and eloquent areas that need to be spared.The aim of this review is to provide an overview of recent developments and practical recommendations for the clinical use of cognitive fMRI in TLE.

Music, Maestro, Please: Thalamic multisensory integration in music perception, processing and production

2019 ◽  
Vol 11 (2) ◽  
pp. 98
Author(s):  
Artur Jaschke
Keyword(s):  
Multisensory Integration ◽  
Music Perception ◽  
Initial Point ◽  
Initial Step ◽  
Brain Regions ◽  
Thalamic Nuclei ◽  
Brain Areas ◽  
Neural Connections ◽  
Parietal Lobes ◽  
The Brain

Music activates a wide array of brain areas involved in different functions such as   perception, processing and execution of music. Understanding musical processes in the brain has multiple implications in the neuro- and health sciences.  Challenging the brain with a multisensory stimulus such as music activates responses beyond the auditory cortex of the temporal lobe. Other areas that are involved include the frontal lobes, parietal lobes, areas of the limbic system such as the amygdala, hippocampus and thalamus, the cerebellum and the brainstem. Nonetheless, there has been no attempt to summarize all involved brain areas in music into one overall encompassing map. This may well be, as there has been no thorough theory introduced, which would allow an initial point of departure in creating such a mapTherefore, a thorough systematic review has been conducted to identify all mentioned neural connections involved in the perception, processing and execution of music.  Communication between the thalamic nuclei is the initial step in multisensory integration, which lies at the base of the neural networks as proposed in this paper. Against this background, this manuscript introduces the to our knowledge first map of all brain regions involved in the perception, processing and execution of music.Consequently, placing thalamic multisensory integration at the core of this atlas allowed us to create a preliminary theory to explain the complexity of music induced brain activation.

scholarly journals Identification of the SNARE complex mediating the exocytosis of NMDA receptors

2016 ◽  
Vol 113 (43) ◽  
pp. 12280-12285 ◽  
Author(s):  
Yi Gu ◽  
Richard L. Huganir
Keyword(s):  
Nmda Receptors ◽  
Hippocampal Neurons ◽  
Total Internal Reflection ◽  
De Novo ◽  
Receptor Trafficking ◽  
Snare Complex ◽  
Synaptic Membranes ◽  
Rab Proteins ◽  
The Central Nervous System ◽  
The Brain

In the central nervous system, NMDA receptors mediate excitatory neurotransmissions and play important roles in synaptic plasticity. The regulation of NMDA receptor trafficking is critical for neural functions in the brain. Here, we directly visualized individual exocytic events of NMDA receptors in rat hippocampal neurons by total internal reflection fluorescence microscopy (TIRFM). We found that the constitutive exocytosis of NMDA receptors included both de novo exocytic and recycling events, which were regulated by different Rab proteins. We also identified the SNAP25–VAMP1–syntaxin4 complex mediating the constitutive exocytosis of NMDA receptors. Transient knockdown of each component of the SNARE complex interfered with surface delivery of NMDA receptors to both extrasynaptic and synaptic membranes. Our study uncovers the postsynaptic function of the SNAP25–VAMP1–syntaxin4 complex in mediating the constitutive exocytosis of NMDA receptors, suggesting that this SNARE complex is involved in excitatory synaptic transmission.

scholarly journals Effects of tiletamine-xylazine-tramadol combination and its specific antagonist on AMPK in the brain of rats

2019 ◽  
Vol 63 (2) ◽  
pp. 285-292
Author(s):  
Ning Ma ◽  
Xin Li ◽  
Hong-bin Wang ◽  
Li Gao ◽  
Jian-hua Xiao
Keyword(s):  
Mrna Expression ◽  
Opposite Effect ◽  
Brain Regions ◽  
Control Group ◽  
Sprague Dawley ◽  
Sd Rats ◽  
The Central Nervous System ◽  
Specific Antagonist ◽  
Sedation And Analgesia ◽  
The Brain

AbstractIntroduction:Tiletamine-xylazine-tramadol (XFM) has few side effects and can provide good sedation and analgesia. Adenosine 5’-monophosphate-activated protein kinase (AMPK) can attenuate trigeminal neuralgia. The study aimed to investigate the effects of XFM and its specific antagonist on AMPK in different regions of the brain.Material and Methods:A model of XFM in the rat was established. A total of 72 Sprague Dawley (SD) rats were randomly divided into three equally sized groups: XFM anaesthesia (M group), antagonist (W group), and XFM with antagonist interactive groups (MW group). Eighteen SD rats were in the control group and were injected intraperitoneally with saline (C group). The rats were sacrificed and the cerebral cortex, cerebellum, hippocampus, thalamus, and brain stem were immediately separated, in order to detect AMPKα mRNA expression by quantitative PCR.Results:XFM was able to increase the mRNA expression of AMPKα1 and AMPKα2 in all brain regions, and the antagonist caused the opposite effect, although the effects of XFM could not be completely reversed in some areas.Conclusion:XFM can influence the expression of AMPK in the central nervous system of the rat, which can provide a reference for the future development of anaesthetics for animals.

scholarly journals A Core Set of Brain Regions Helps Kids Achieve Their Goals

2021 ◽  
Vol 9 ◽  
Author(s):  
AnnaCarolina Garza ◽  
Alice Aizza ◽  
Janchira K. Charoenworawat ◽  
Jessica A. Church
Keyword(s):  
Young People ◽  
Executive Functions ◽  
Brain Regions ◽  
Simple Games ◽  
Brain Areas ◽  
Core Set ◽  
The Brain

Your brain is always adjusting to the changing swirl of activities and interactions you have every day. Every time you accomplish a goal, you are exercising what are called the brain’s executive functions. These skills include resisting impulses, switching between tasks, and updating information in your memory. We asked whether these different skills relied on the same brain areas, and whether young people used the same brain areas as adults. We took pictures of kids’ and teens’ brains to see which areas of the brain they were using while they played three simple games related to these executive functions. We found that youth used similar brain regions to adults while playing the three games, and that many parts of the brain were used across all three games. These results help us understand how kids use their brains to be successful and how these skills develop.

scholarly journals Astrocytes, Noradrenaline, α1-Adrenoreceptors, and Neuromodulation: Evidence and Unanswered Questions

2021 ◽  
Vol 15 ◽  
Author(s):  
Jérôme Wahis ◽  
Matthew G. Holt
Keyword(s):  
Critical Appraisal ◽  
Brain Regions ◽  
Synaptic Activity ◽  
Physiological Effects ◽  
Astrocyte Heterogeneity ◽  
Main Effect ◽  
The Central Nervous System ◽  
Noradrenergic Modulation ◽  
The Brain ◽  
Experimental Strategies

Noradrenaline is a major neuromodulator in the central nervous system (CNS). It is released from varicosities on neuronal efferents, which originate principally from the main noradrenergic nuclei of the brain – the locus coeruleus – and spread throughout the parenchyma. Noradrenaline is released in response to various stimuli and has complex physiological effects, in large part due to the wide diversity of noradrenergic receptors expressed in the brain, which trigger diverse signaling pathways. In general, however, its main effect on CNS function appears to be to increase arousal state. Although the effects of noradrenaline have been researched extensively, the majority of studies have assumed that noradrenaline exerts its effects by acting directly on neurons. However, neurons are not the only cells in the CNS expressing noradrenaline receptors. Astrocytes are responsive to a range of neuromodulators – including noradrenaline. In fact, noradrenaline evokes robust calcium transients in astrocytes across brain regions, through activation of α1-adrenoreceptors. Crucially, astrocytes ensheath neurons at synapses and are known to modulate synaptic activity. Hence, astrocytes are in a key position to relay, or amplify, the effects of noradrenaline on neurons, most notably by modulating inhibitory transmission. Based on a critical appraisal of the current literature, we use this review to argue that a better understanding of astrocyte-mediated noradrenaline signaling is therefore essential, if we are ever to fully understand CNS function. We discuss the emerging concept of astrocyte heterogeneity and speculate on how this might impact the noradrenergic modulation of neuronal circuits. Finally, we outline possible experimental strategies to clearly delineate the role(s) of astrocytes in noradrenergic signaling, and neuromodulation in general, highlighting the urgent need for more specific and flexible experimental tools.

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