scholarly journals Intraneuronal chloride accumulation via NKCC1 is not essential for hippocampal network development in vivo

2020 ◽  
Author(s):  
Jürgen Graf ◽  
Chuanqiang Zhang ◽  
Stephan Lawrence Marguet ◽  
Tanja Herrmann ◽  
Tom Flossmann ◽  
...  
Keyword(s):  
Cognitive Abilities ◽  
Network Dynamics ◽  
Brain Slices ◽  
Network Activity ◽  
Long Term Effects ◽  
Network Function ◽  
Excitatory Gaba ◽  
A Minor

AbstractNKCC1 is the primary transporter mediating chloride uptake in immature principal neurons, but its role in the development of in vivo network dynamics and cognitive abilities remains unknown. Here, we address the function of NKCC1 in developing mice using electrophysiological, optical and behavioral approaches. We report that NKCC1 deletion from telencephalic glutamatergic neurons decreases in-vitro excitatory GABA actions and impairs neuronal synchrony in neonatal hippocampal brain slices. In vivo, it has a minor impact on correlated spontaneous activity in the hippocampus and does not affect network activity in the intact visual cortex. Moreover, long-term effects of the developmental NKCC1 deletion on synaptic maturation, network dynamics and behavioral performance are subtle. Our data reveal a neural network function of depolarizing GABA in the hippocampus in vivo, but challenge the hypothesis that NKCC1 is essential for major aspects of hippocampal development.

scholarly journals A limited role of NKCC1 in telencephalic glutamatergic neurons for developing hippocampal network dynamics and behavior

2021 ◽  
Vol 118 (14) ◽  
pp. e2014784118
Author(s):  
Jürgen Graf ◽  
Chuanqiang Zhang ◽  
Stephan Lawrence Marguet ◽  
Tanja Herrmann ◽  
Tom Flossmann ◽  
...  
Keyword(s):  
Cognitive Abilities ◽  
Network Dynamics ◽  
Brain Slices ◽  
Network Activity ◽  
Long Term Effects ◽  
Network Function ◽  
Glutamatergic Neurons ◽  
A Minor

NKCC1 is the primary transporter mediating chloride uptake in immature principal neurons, but its role in the development of in vivo network dynamics and cognitive abilities remains unknown. Here, we address the function of NKCC1 in developing mice using electrophysiological, optical, and behavioral approaches. We report that NKCC1 deletion from telencephalic glutamatergic neurons decreases in vitro excitatory actions of γ-aminobutyric acid (GABA) and impairs neuronal synchrony in neonatal hippocampal brain slices. In vivo, it has a minor impact on correlated spontaneous activity in the hippocampus and does not affect network activity in the intact visual cortex. Moreover, long-term effects of the developmental NKCC1 deletion on synaptic maturation, network dynamics, and behavioral performance are subtle. Our data reveal a neural network function of NKCC1 in hippocampal glutamatergic neurons in vivo, but challenge the hypothesis that NKCC1 is essential for major aspects of hippocampal development.

scholarly journals Neurokinin B regulates reproduction via inhibition of kisspeptin in a teleost, the striped bass

2017 ◽  
Vol 233 (2) ◽  
pp. 159-174 ◽  
Author(s):  
Nilli Zmora ◽  
Ten-Tsao Wong ◽  
John Stubblefield ◽  
Berta Levavi-Sivan ◽  
Yonathan Zohar
Keyword(s):  
Striped Bass ◽  
Brain Slices ◽  
Neuronal Population ◽  
Minor Effect ◽  
Pituitary Cells ◽  
Neurokinin B ◽  
A Minor ◽  
Lh Secretion

Kisspeptin and neurokinin B (NKB) are neuropeptides co-expressed in the mammalian hypothalamus and coordinately control GnRH signaling. We have found that Nkb and kisspeptin neurons are distinct in the teleost, striped bass (STB) and capitalized on this phenomenon to study the mode of action of Nkb and its related neuropeptide-F (Nkf), both of which are encoded by the tac3 gene. In vitro brain slices and in vivo administration studies revealed that Nkb/f consistently downregulated kiss2, whereas antagonist (AntD) administration restored this effect. Overall, a minor effect was noted on gnrh1 expression, whereas Gnrh1 content in the pituitaries was reduced after Nkb/f treatment and increased with AntD. Concomitantly, immunostaining demonstrated that hypothalamic Nkb neurons border and densely innervate the largest kiss2 neuronal population in the hypothalamus, which also coexpresses Nkb receptor. No expression of Nkb receptor or Nkb neuronal projections was detected near/in Gnrh1 soma in the preoptic area. At the level of the pituitary, however, the picture was more complex: both Nkb/f and AntD upregulated lhb and fshb expression and Lh secretion in vivo. Together with the stimulatory effect of Nkb/f on Lh/Fsh secretion from pituitary cells, in vitro, this may indicate an additional independent action of Nkb/f within the pituitary, in which the hypothalamic pathway is more dominant. The current study demonstrates that Nkb/f utilizes multiple pathways to regulate reproduction in the STB and that in the brain, Nkb mainly acts as a negative modulator of kiss2 to regulate the release of Gnrh1.

Alterations in Piriform and Bulbar Activity/Excitability/Coupling Upon Amyloid-β Administration in vivo Related to Olfactory Dysfunction

2021 ◽  
pp. 1-17
Author(s):  
Ignacio Martínez-García ◽  
Rebeca Hernández-Soto ◽  
Benjamín Villasana-Salazar ◽  
Benito Ordaz ◽  
Fernando Peña-Ortega
Keyword(s):  
Piriform Cortex ◽  
Brain Slices ◽  
Amyloid Β ◽  
Olfactory Dysfunction ◽  
Network Activity ◽  
Pathological Changes ◽  
Olfactory Pathway ◽  
Lateral Olfactory Tract

Background: Deficits in odor detection and discrimination are premature symptoms of Alzheimer’s disease (AD) that correlate with pathological signs in the olfactory bulb (OB) and piriform cortex (PCx). Similar olfactory dysfunction has been characterized in AD transgenic mice that overproduce amyloid-β (Aβ), which can be prevented by reducing Aβ levels by immunological and pharmacological means, suggesting that olfactory dysfunction depends on Aβ accumulation and Aβ-driven alterations in the OB and/or PCx, as well as on their activation. However, this possibility was not directly tested before. Objective: To characterize the effects of Aβ on OB and PCx excitability/coupling and on olfaction. Methods: Aβ oligomerized solution (containing oligomers, monomers, and protofibrils) or its vehicle were intracerebroventricularlly injected two weeks before OB and PCx excitability and synchrony were evaluated through field recordings in vivo and in brain slices. Synaptic transmission from the OB to the PCx was also evaluated in vitro. Olfaction was assessed through the habituation/dishabituation test. Results: Aβ did not affect lateral olfactory tract transmission into the PCx but reduced odor habituation and cross-habituation. This olfactory dysfunction was related to a reduction of PCx and OB network activity power in vivo. Moreover, the coherence between PCx-OB activities was also reduced by Aβ. Finally, Aβ treatment exacerbated the 4-aminopyridine-induced excitation in the PCx in vitro. Conclusion: Our results show that Aβ-induced olfactory dysfunction involves a complex set of pathological changes at different levels of the olfactory pathway including alterations in PCx excitability and its coupling with the OB. These pathological changes might contribute to hyposmia in AD.

scholarly journals Evaluation of in vitro neuronal networks for the study of spontaneous activity

STEMedicine ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. e35 ◽  
Author(s):  
Diletta Pozzi
Keyword(s):  
Nervous System ◽  
Spontaneous Activity ◽  
Time Course ◽  
Neuronal Networks ◽  
Brain Slices ◽  
In Vitro Models ◽  
Network Activity ◽  
External Stimuli

In the absence of external stimuli, the nervous system exhibits a spontaneous electrical activity whose functions are not fully understood, and that represents the background noise of brain operations. Spontaneous activity has been proven to arise not only in vivo, but in in vitro neuronal networks as well, following some stereotypical patterns that reproduce the time course of development of the mammalian nervous system. This review provides an overview of in vitro models for the study of spontaneous network activity, discussing their ability to reproduce in vivo - like dynamics and the main findings obtained with each particular model. While explanted brain slices are able to reproduce the neuronal oscillations typically observed in anaesthetized animals, dissociated cultures allow the use of patient-derived neurons and limit the number of animals used for sample preparation.

scholarly journals Neurosteroids and Focal Epileptic Disorders

2020 ◽  
Vol 21 (24) ◽  
pp. 9391
Author(s):  
Maxime Lévesque ◽  
Giuseppe Biagini ◽  
Massimo Avoli
Keyword(s):  
Brain Slices ◽  
Mesial Temporal Lobe Epilepsy ◽  
Epileptic Activity ◽  
Network Activity ◽  
Interictal Spikes ◽  
In Vivo Models ◽  
High Frequency Oscillations ◽  
Spontaneous Seizures

Neurosteroids are a family of compounds that are synthesized in principal excitatory neurons and glial cells, and derive from the transformation of cholesterol into pregnenolone. The most studied neurosteroids—allopregnanolone and allotetrahydrodeoxycorticosterone (THDOC)—are known to modulate GABAA receptor-mediated transmission, thus playing a role in controlling neuronal network excitability. Given the role of GABAA signaling in epileptic disorders, neurosteroids have profound effects on seizure generation and play a role in the development of chronic epileptic conditions (i.e., epileptogenesis). We review here studies showing the effects induced by neurosteroids on epileptiform synchronization in in vitro brain slices, on epileptic activity in in vivo models, i.e., in animals that were made epileptic with chemoconvulsant treatment, and in epileptic patients. These studies reveal that neurosteroids can modulate ictogenesis and the occurrence of pathological network activity such as interictal spikes and high-frequency oscillations (80–500 Hz). Moreover, they can delay the onset of spontaneous seizures in animal models of mesial temporal lobe epilepsy. Overall, this evidence suggests that neurosteroids represent a new target for the treatment of focal epileptic disorders.

scholarly journals Criticality as a measure of developing proteinopathy in engineered human neural networks

2020 ◽  
Author(s):  
Vibeke Devold Valderhaug ◽  
Kristine Heiney ◽  
Ola Huse Ramstad ◽  
Geir Braathen ◽  
Wei-Li Kuan ◽  
...  
Keyword(s):  
Neural Networks ◽  
Lewy Bodies ◽  
Functional Trait ◽  
Alpha Synuclein ◽  
Network Activity ◽  
Multielectrode Arrays ◽  
Lewy Neurites ◽  
Network Function

A patterned spread of proteinopathy represents a common characteristic of many neurodegenerative diseases. In Parkinson's disease (PD), misfolded forms of alpha-synuclein proteins aggregate and accumulate in hallmark pathological inclusions termed Lewy bodies and Lewy neurites, which seems to affect selectively vulnerable neuronal populations and propagate within interconnected neuronal networks. Research findings suggest that these proteinopathic inclusions are present at very early timepoints in disease development, even before strong behavioural symptoms of dysfunction arise, but that these underlying pathologies might be masked by homeostatic processes working to maintain the function of the degenerating neural circuits. This study investigates whether inducing the PD-related alpha-synuclein pathology in engineered human neural networks can be associated with changes in network function, and particularly with network criticality states. Self-organised criticality represents the critical point between resilience against perturbation and adaptational flexibility, which appears to be a functional trait in self-organising neural networks, both in vitro and in vivo. By monitoring the developing neural network activity through the use of multielectrode arrays (MEAs) for a period of three weeks following proteinopathy induction, we show that although this developing pathology is not clearly manifest in standard measurements of network function, it may be discerned by differences in network criticality states.

Dementia with Lewy bodies—associated ß-synuclein mutations V70M and P123H cause mutation-specific neuropathological lesions

2021 ◽  
Author(s):  
Maryna Psol ◽  
Sofia Guerin Darvas ◽  
Kristian Leite ◽  
Sameehan U Mahajani ◽  
Mathias Bähr ◽  
...  
Keyword(s):  
Neuronal Network ◽  
Dementia With Lewy Bodies ◽  
Lewy Bodies ◽  
Sporadic Case ◽  
Network Activity ◽  
Proteinase K ◽  
Neuronal Network Activity ◽  
Distinct Disease

Abstract ß-Synuclein (ß-Syn) has long been considered to be an attenuator for the neuropathological effects caused by the Parkinson’s disease-related α-Synuclein (α-Syn) protein. However, recent studies demonstrated that overabundant ß-Syn can form aggregates and induce neurodegeneration in CNS neurons in vitro and in vivo, albeit at a slower pace as compared to α-Syn. Here we demonstrate that ß-Syn mutants V70M, detected in a sporadic case of Dementia with Lewy Bodies (DLB), and P123H, detected in a familial case of DLB, robustly aggravate the neurotoxic potential of ß-Syn. Intriguingly, the two mutations trigger mutually exclusive pathways. ß-Syn V70M enhances morphological mitochondrial deterioration and degeneration of dopaminergic and non-dopaminergic neurons, but has no influence on neuronal network activity. Conversely, ß-Syn P123H silences neuronal network activity, but does not aggravate neurodegeneration. ß-Syn WT, V70M and P123H formed proteinase K (PK) resistant intracellular fibrils within neurons, albeit with less stable C-termini as compared to α-Syn. Under cell free conditions, ß-Syn V70M demonstrated a much slower pace of fibril formation as compared to WT ß-Syn, and P123H fibrils present with a unique phenotype characterized by large numbers of short, truncated fibrils. Thus, it is possible that V70M and P123H cause structural alterations in ß-Syn, that are linked to their distinct neuropathological profiles. The extent of the lesions caused by these neuropathological profiles is almost identical to that of overabundant α-Syn, and thus likely to be directly involved into etiology of DLB. Over all, this study provides insights into distinct disease mechanisms caused by mutations of ß-Syn.

scholarly journals Development of 18F-Labeled Radiotracers for PET Imaging of the Adenosine A2A Receptor: Synthesis, Radiolabeling and Preliminary Biological Evaluation

2021 ◽  
Vol 22 (5) ◽  
pp. 2285
Author(s):  
Thu Hang Lai ◽  
Susann Schröder ◽  
Magali Toussaint ◽  
Sladjana Dukić-Stefanović ◽  
Mathias Kranz ◽  
...  
Keyword(s):  
Specific Binding ◽  
Brain Slices ◽  
Total Activity ◽  
Biological Evaluation ◽  
Adenosine A2a Receptor ◽  
Positron Emission ◽  
A2a Receptor ◽  
Adenosine A2a

The adenosine A2A receptor (A2AR) represents a potential therapeutic target for neurodegenerative diseases. Aiming at the development of a positron emission tomography (PET) radiotracer to monitor changes of receptor density and/or occupancy during the A2AR-tailored therapy, we designed a library of fluorinated analogs based on a recently published lead compound (PPY). Among those, the highly affine 4-fluorobenzyl derivate (PPY1; Ki(hA2AR) = 5.3 nM) and the 2-fluorobenzyl derivate (PPY2; Ki(hA2AR) = 2.1 nM) were chosen for 18F-labeling via an alcohol-enhanced copper-mediated procedure starting from the corresponding boronic acid pinacol ester precursors. Investigations of the metabolic stability of [18F]PPY1 and [18F]PPY2 in CD-1 mice by radio-HPLC analysis revealed parent fractions of more than 76% of total activity in the brain. Specific binding of [18F]PPY2 on mice brain slices was demonstrated by in vitro autoradiography. In vivo PET/magnetic resonance imaging (MRI) studies in CD-1 mice revealed a reasonable high initial brain uptake for both radiotracers, followed by a fast clearance.

Physiology, Pharmacology, and Topography of Cholinergic Neocortical Oscillations In Vitro

1997 ◽  
Vol 77 (5) ◽  
pp. 2427-2445 ◽  
Author(s):  
Heath S. Lukatch ◽  
M. Bruce Maciver
Keyword(s):  
Current Source ◽  
Brain Slices ◽  
Receptor Activation ◽  
Brain Regions ◽  
Oscillatory Activity ◽  
Cortical Layers ◽  
Eeg Activity ◽  
Layer 2

Lukatch, Heath S. and M. Bruce MacIver. Physiology, pharmacology, and topography of cholinergic neocortical oscillations in vitro. J. Neurophysiol. 77: 2427–2445, 1997. Rat neocortical brain slices generated rhythmic extracellular field [microelectroencephalogram (micro-EEG)] oscillations at theta frequencies (3–12 Hz) when exposed to pharmacological conditions that mimicked endogenous ascending cholinergic and GABAergic inputs. Use of the specific receptor agonist and antagonist carbachol and bicuculline revealed that simultaneous muscarinic receptor activation and γ-aminobutyric acid-A (GABAA)-mediated disinhibition werenecessary to elicit neocortical oscillations. Rhythmic activity was independent of GABAB receptor activation, but required intact glutamatergic transmission, evidenced by blockade or disruption of oscillations by 6-cyano-7-nitroquinoxaline-2,3-dione and (±)-2-amino-5-phosphonovaleric acid, respectively. Multisite mapping studies showed that oscillations were localized to areas 29d and 18b (Oc2MM) and parts of areas 18a and 17. Peak oscillation amplitudes occurred in layer 2/3, and phase reversals were observed in layers 1 and 5. Current source density analysis revealed large-amplitude current sinks and sources in layers 2/3 and 5, respectively. An initial shift in peak inward current density from layer 1 to layer 2/3 indicated that two processes underlie an initial depolarization followed by oscillatory activity. Laminar transections localized oscillation-generating circuitry to superficial cortical layers and sharp-spike-generating circuitry to deep cortical layers. Whole cell recordings identified three distinct cell types based on response properties during rhythmic micro-EEG activity: oscillation-on (theta-on) and -off (theta-off) neurons, and transiently depolarizing glial cells. Theta-on neurons displayed membrane potential oscillations that increased in amplitude with hyperpolarization (from −30 to −90 mV). This, taken together with a glutamate antagonist-induced depression of rhythmic micro-EEG activity, indicated that cholinergically driven neocortical oscillations require excitatory synaptic transmission. We conclude that under the appropriate pharmacological conditions, neocortical brain slices were capable of producing localized theta frequency oscillations. Experiments examining oscillation physiology, pharmacology, and topography demonstrated that neocortical brain slice oscillations share many similarities with the in vivo and in vitro theta EEG activity recorded in other brain regions.

scholarly journals Simulated diabetic ketoacidosis therapy in vitro elicits brain cell swelling via sodium-hydrogen exchange and anion transport

2015 ◽  
Vol 309 (4) ◽  
pp. E370-E379 ◽  
Author(s):  
Keeley L. Rose ◽  
Andrew J. Watson ◽  
Thomas A. Drysdale ◽  
Gediminas Cepinskas ◽  
Melissa Chan ◽  
...  
Keyword(s):  
Diabetic Ketoacidosis ◽  
Hydrogen Exchange ◽  
Brain Slices ◽  
Anion Transport ◽  
Brain Cell ◽  
Cell Swelling ◽  
Sodium Hydrogen ◽  
Disulphonic Acid

A common complication of type 1 diabetes mellitus is diabetic ketoacidosis (DKA), a state of severe insulin deficiency. A potentially harmful consequence of DKA therapy in children is cerebral edema (DKA-CE); however, the mechanisms of therapy-induced DKA-CE are unknown. Our aims were to identify the DKA treatment factors and membrane mechanisms that might contribute specifically to brain cell swelling. To this end, DKA was induced in juvenile mice with the administration of the pancreatic toxins streptozocin and alloxan. Brain slices were prepared and exposed to DKA-like conditions in vitro. Cell volume changes were imaged in response to simulated DKA therapy. Our experiments showed that cell swelling was elicited with isolated DKA treatment components, including alkalinization, insulin/alkalinization, and rapid reductions in osmolality. Methyl-isobutyl-amiloride, a nonselective inhibitor of sodium-hydrogen exchangers (NHEs), reduced cell swelling in brain slices elicited with simulated DKA therapy (in vitro) and decreased brain water content in juvenile DKA mice administered insulin and rehydration therapy (in vivo). Specific pharmacological inhibition of the NHE1 isoform with cariporide also inhibited cell swelling, but only in the presence of the anion transport (AT) inhibitor 4,4′-diisothiocyanatostilbene-2,2′-disulphonic acid. DKA did not alter brain NHE1 isoform expression, suggesting that the cell swelling attributed to the NHE1 was activity dependent. In conclusion, our data raise the possibility that brain cell swelling can be elicited by DKA treatment factors and that it is mediated by NHEs and/or coactivation of NHE1 and AT.

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