scholarly journals A Possible Link Between HCN Channels and Depression

2018 ◽  
Vol 2 ◽  
pp. 247054701878778 ◽  
Author(s):  
Chung Sub Kim ◽  
Daniel Johnston
Keyword(s):  
Protein Expression ◽  
Neuronal Excitability ◽  
Acute Stress ◽  
Hcn Channels ◽  
Chronic Unpredictable Stress ◽  
Ca1 Neurons ◽  
Ca1 Region ◽  
Hcn1 Channels ◽  
The Brain

Growing evidence suggests a possible link between hyperpolarization-activated cyclic nucleotide-gated nonselective cation (HCN) channels and depression. In a recent study published in Molecular Psychiatry, we first demonstrate that Ih (the membrane current mediated by HCN channels) and HCN1 protein expression were increased in dorsal, but not in ventral, CA1 region following chronic, but not acute stress. This upregulation of Ih was restricted to the perisomatic region of CA1 neurons and contributed to a reduction of neuronal excitability. A reduction of HCN1 protein expression in dorsal CA1 region before the onset of chronic unpredictable stress-induced depression was sufficient to provide resilient effects to chronic unpredictable stress. Furthermore, in vivo block of the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) pumps, a manipulation known to increase intracellular calcium levels and upregulate Ih, produced anxiogenic-like behavior and an increase in Ih, similar to that observed in chronic unpredictable stress model of depression. Here, we share our view on (1) how the function and expression of HCN1 channels are changed in the brain in a subcellular region-specific manner during the development of depression and (2) how a reduction of HCN1 protein expression provides resilience to chronic stress.

scholarly journals C60 Fullerene Prevents Restraint Stress-Induced Oxidative Disorders in Rat Tissues: Possible Involvement of the Nrf2/ARE-Antioxidant Pathway

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Olga O. Gonchar ◽  
Andriy V. Maznychenko ◽  
Nataliya V. Bulgakova ◽  
Inna V. Vereshchaka ◽  
Tomasz Tomiak ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Protein Expression ◽  
Restraint Stress ◽  
Stress Condition ◽  
Rat Tissues ◽  
Stress Exposure ◽  
The Brain ◽  
Nrf2 Protein

The effects of C60FAS (50 and 500 μg/kg) supplementation, in a normal physiological state and after restraint stress exposure, on prooxidant/antioxidant balance in rat tissues were explored and compared with the effects of the known exogenous antioxidant N-acetylcysteine. Oxidative stress biomarkers (ROS, O2⋅−, H2O2, and lipid peroxidation) and indices of antioxidant status (MnSOD, catalase, GPx, GST, γ-GCL, GR activities, and GSH level) were measured in the brain and the heart. In addition, protein expression of Nrf2 in the nuclear and cytosol fractions as well as the protein level of antiradical enzyme MnSOD and GSH-related enzymes γ-GCLC, GPx, and GSTP as downstream targets of Nrf2 was evaluated by western blot analysis. Under a stress condition, C60FAS attenuates ROS generation and O2⋅− and H2O2 releases and thus decreases lipid peroxidation as well as increases rat tissue antioxidant capacity. We have shown that C60FAS supplementation has dose-dependent and tissue-specific effects. C60FAS strengthened the antiradical defense through the upregulation of MnSOD in brain cells and maintained MnSOD protein content at the control level in the myocardium. Moreover, C60FAS enhanced the GSH level and the activity/protein expression of GSH-related enzymes. Correlation of these changes with Nrf2 protein content suggests that under stress exposure, along with other mechanisms, the Nrf2/ARE-antioxidant pathway may be involved in regulation of glutathione homeostasis. In our study, in an in vivo model, when C60FAS (50 and 500 μg/kg) was applied alone, no significant changes in Nrf2 protein expression as well as in activity/protein levels of MnSOD and GSH-related enzymes in both tissues types were observed. All these facts allow us to assume that in the in vivo model, C60FAS affects on the brain and heart endogenous antioxidative statuses only during the oxidative stress condition.

scholarly journals Reappearance of Hippocampal CA1 Neurons after Ischemia is Associated with Recovery of Learning and Memory

2005 ◽  
Vol 25 (12) ◽  
pp. 1586-1595 ◽  
Author(s):  
Olof Bendel ◽  
Tjerk Bueters ◽  
Mia von Euler ◽  
Sven Ove Ögren ◽  
Johan Sandin ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Learning And Memory ◽  
Spatial Learning ◽  
Cognitive Functions ◽  
Spatial Learning And Memory ◽  
Neuronal Marker ◽  
Ca1 Neurons ◽  
Ca1 Region ◽  
Hippocampal Ca1 ◽  
The Brain

The pyramidal neurons of the hippocampal CA1 region are essential for cognitive functions such as spatial learning and memory, and are selectively destroyed after cerebral ischemia. To analyze whether degenerated CA1 neurons are replaced by new neurons and whether such regeneration is associated with amelioration in learning and memory deficits, we have used a rat global ischemia model that provides an almost complete disappearance (to approximately 3% of control) of CA1 neurons associated with a robust impairment in spatial learning and memory at two weeks after ischemia. We found that transient cerebral ischemia can evoke a massive formation of new neurons in the CA1 region, reaching approximately 40% of the original number of neurons at 90 days after ischemia (DAI). Co-localization of the mature neuronal marker neuronal nuclei with 5-bromo-2'-deoxyuridine in CA1 confirmed that neurogenesis indeed had occurred after the ischemic insult. Furthermore, we found increased numbers of cells expressing the immature neuron marker polysialic acid neuronal cell adhesion molecule in the adjacent lateral periventricular region, suggesting that the newly formed neurons derive from this region. The reappearance of CA1 neurons was associated with a recovery of ischemia-induced impairments in spatial learning and memory at 90 DAI, suggesting that the newly formed CA1 neurons restore hippocampal CA1 function. In conclusion, these results show that the brain has an endogenous capacity to form new nerve cells after injury, which correlates with a restoration of cognitive functions of the brain.

scholarly journals Noise and Coupling Affect Signal Detection and Bursting in a Simulated Physiological Neural Network

2002 ◽  
Vol 88 (5) ◽  
pp. 2598-2611 ◽  
Author(s):  
William C. Stacey ◽  
Dominique M. Durand
Keyword(s):  
Signal Detection ◽  
Epileptiform Activity ◽  
Electrical Coupling ◽  
Periodic Signal ◽  
Physiological Noise ◽  
Ca1 Neurons ◽  
Ca1 Region ◽  
Noise Characteristics ◽  
Hippocampal Ca1

Signal detection in the CNS relies on a complex interaction between the numerous synaptic inputs to the detecting cells. Two effects, stochastic resonance (SR) and coherence resonance (CR) have been shown to affect signal detection in arrays of basic neuronal models. Here, an array of simulated hippocampal CA1 neurons was used to test the hypothesis that physiological noise and electrical coupling can interact to modulate signal detection in the CA1 region of the hippocampus. The array was tested using varying levels of coupling and noise with different input signals. Detection of a subthreshold signal in the network improved as the number of detecting cells increased and as coupling was increased as predicted by previous studies in SR; however, the response depended greatly on the noise characteristics present and varied from SR predictions at times. Careful evaluation of noise characteristics may be necessary to form conclusions about the role of SR in complex systems such as physiological neurons. The coupled array fired synchronous, periodic bursts when presented with noise alone. The synchrony of this firing changed as a function of noise and coupling as predicted by CR. The firing was very similar to certain models of epileptiform activity, leading to a discussion of CR as a possible simple model of epilepsy. A single neuron was unable to recruit its neighbors to a periodic signal unless the signal was very close to the synchronous bursting frequency. These findings, when viewed in comparison with physiological parameters in the hippocampus, suggest that both SR and CR can have significant effects on signal processing in vivo.

scholarly journals Latrophilin GPCR Signaling Mediates Synapse Formation

2021 ◽  
Author(s):  
Richard Sando ◽  
Thomas C. Südhof
Keyword(s):  
Synapse Formation ◽  
Neural Circuit ◽  
Gpcr Signaling ◽  
Synapse Loss ◽  
Ca1 Region ◽  
In Trans ◽  
Synaptic Complexes ◽  
Camp Levels ◽  
The Brain

ABSTRACTNeural circuit assembly in the brain requires precise establishment of synaptic connections, but the mechanisms of synapse assembly remain incompletely understood. Latrophilins are postsynaptic adhesion-GPCRs that engage in trans-synaptic complexes with presynaptic teneurins and FLRTs. In CA1-region neurons, Latrophilin-2 and Latrophilin-3 are essential for formation of entorhinal-cortex-derived and Schaffer-collateral-derived synapses, respectively. However, it is unknown whether latrophilins function as GPCRs in synapse formation. Here, we show that Latrophilin-2 and Latrophilin-3 exhibit constitutive GPCR activity that increases cAMP levels, which was blocked by a mutation interfering with G-protein and arrestin interactions of GPCRs. The same mutation impaired the ability of Latrophilin-2 and Latrophilin-3 to rescue the synapse-loss phenotype in Latrophilin-2 and Latrophilin-3 knockout neurons in vivo. Our results suggest that Latrophilin-2 and Latrophilin-3 require GPCR signaling in synapse formation, indicating that latrophilins promote synapse formation in the hippocampus by activating a classical GPCR-signaling pathway.

scholarly journals PRMT7 deficiency causes dysregulation of the HCN channels in the CA1 pyramidal cells and impairment of social behaviors

2020 ◽  
Vol 52 (4) ◽  
pp. 604-614
Author(s):  
Seul-Yi Lee ◽  
Tuan Anh Vuong ◽  
Hyun-Kyung So ◽  
Hyun-Ji Kim ◽  
Yoo Bin Kim ◽  
...  
Keyword(s):  
Pyramidal Cells ◽  
Neuropsychiatric Disorders ◽  
Autism Spectrum ◽  
Resting Potential ◽  
Hcn Channels ◽  
Hcn Channel ◽  
Ca1 Neurons ◽  
Protein Levels ◽  
Ca1 Pyramidal Cells ◽  
Ca1 Region

Abstract HCN channels regulate excitability and rhythmicity in the hippocampal CA1 pyramidal cells. Perturbation in the HCN channel current (Ih) is associated with neuropsychiatric disorders, such as autism spectrum disorders. Recently, protein arginine methyltransferase 7 (PRMT7) was shown to be highly expressed in the hippocampus, including the CA1 region. However, the physiological function of PRMT7 in the CA1 neurons and the relationship to psychiatric disorders are unclear. Here we showed that PRMT7 knockout (KO) mice exhibit hyperactivity and deficits in social interaction. The firing frequency of the CA1 neurons in the PRMT7 KO mice was significantly higher than that in the wild-type (WT) mice. Compared with the WT CA1 neurons, the PRMT7 KO CA1 neurons showed a more hyperpolarized resting potential and a higher input resistance, which were occluded by the Ih-current inhibitor ZD7288; these findings were consistent with the decreased Ih and suggested the contribution of Ih-channel dysfunction to the PRMT7 KO phenotypes. The HCN1 protein level was decreased in the CA1 region of the PRMT7 KO mice in conjunction with a decrease in the expression of Shank3, which encodes a core scaffolding protein for HCN channel proteins. A brief application of the PRMT7 inhibitor DS437 did not reproduce the phenotype of the PRMT7 KO neurons, further indicating that PRMT7 regulates Ih by controlling the channel number rather than the open probability. Moreover, shRNA-mediated PRMT7 suppression reduced both the mRNA and protein levels of SHANK3, implying that PRMT7 deficiency might be responsible for the decrease in the HCN protein levels by altering Shank3 expression. These findings reveal a key role for PRMT7 in the regulation of HCN channel density in the CA1 pyramidal cells that may be amenable to pharmacological intervention for neuropsychiatric disorders.

scholarly journals Lamotrigine Attenuates Neuronal Excitability, Depresses GABA Synaptic Inhibition, and Modulates Theta Rhythms in Rat Hippocampus

2021 ◽  
Author(s):  
Paulina Kazmierska-Grebowska ◽  
Marcin Siwiec ◽  
Joanna Ewa Sowa ◽  
Caban Bartosz ◽  
Tomasz Kowalczyk ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Neuronal Excitability ◽  
Medial Septum ◽  
Movement Planning ◽  
Theta Oscillations ◽  
Hcn Channels ◽  
Anaesthetized Rats ◽  
Hippocampal Theta

Theta oscillations generated in hippocampal (HPC) and cortical neuronal networks are involved in various aspects of brain function, including sensorimotor integration, movement planning, memory formation and attention. Disruptions of theta rhythms are present in individuals with various disorders, including epilepsy and Alzheimer’s disease. Theta rhythm generation involves a specific interplay between cellular (ionic) and network (synaptic) mechanisms. HCN channels are theta modulators, and several medications are known to enhance their activity. We investigated how different doses of lamotrigine (LTG), an HCN channel activator, and antiepileptic and neuroprotective agent, would affect hippocampal theta rhythms in acute HPC slices (in vitro) and anaesthetized rats (in vivo). Whole-cell patch clamp recordings revealed that LTG decreased GABAA-fast transmission in CA3 and CA1 cells, in vitro. In addition, LTG directly depressed CA3 and CA1 pyramidal neuron excitability. These effects were partially blocked by ZD 7288, a selective HCN blocker, and are consistent with decreased excitability associated with antiepileptic actions. Lamotrigine also depressed hippocampal theta oscillations in vitro, also consistent with its neuronal depressant effects. In contrast, it exerted an opposite, enhancing effect, on theta recorded in vivo. The contradictory in vivo and in vitro results indicate that LTG increases ascending theta activating medial septum/entorhinal synaptic inputs that over-power the depressant effects seen in hippocampal neurons. These results provide new insights into LTG actions and indicate an opportunity to develop more precise therapeutics for the treatment of dementias, memory disorders and epilepsy.

Extracellular Potassium and Seizures: Excitation, Inhibition and the Role of Ih

2016 ◽  
Vol 26 (08) ◽  
pp. 1650044 ◽  
Author(s):  
Lihua Wang ◽  
Suzie Dufour ◽  
Taufik A. Valiante ◽  
Peter L. Carlen
Keyword(s):  
Neuronal Excitability ◽  
Seizure Activity ◽  
Membrane Properties ◽  
Resting Membrane Potential ◽  
Extracellular Potassium ◽  
Hcn Channels ◽  
Extracellular Potassium Concentration ◽  
Prolonged Seizure

Seizure activity leads to increases in extracellular potassium concentration ([K[Formula: see text]]o), which can result in changes in neuronal passive and active membrane properties as well as in population activities. In this study, we examined how extracellular potassium modulates seizure activities using an acute 4-AP induced seizure model in the neocortex, both in vivo and in vitro. Moderately elevated [K[Formula: see text]]o up to 9[Formula: see text]mM prolonged seizure durations and shortened interictal intervals as well as depolarized the neuronal resting membrane potential (RMP). However, when [K[Formula: see text]]o reached higher than 9[Formula: see text]mM, seizure like events (SLEs) were blocked and neurons went into a depolarization-blocked state. Spreading depression was never observed as the blockade of ictal events could be reversed within 1–2[Formula: see text]min after the raised [K[Formula: see text]]o was changed back to control levels. This concentration-dependent dual effect of [K[Formula: see text]]o was observed using in vivo and in vitro mouse brain preparations as well as in human neocortical tissue resected during epilepsy surgery. Blocking the Ih current, mediated by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, modulated the elevated [K[Formula: see text]]o influence on SLEs by promoting the high [K[Formula: see text]]o inhibitory actions. These results demonstrate biphasic actions of raised [K[Formula: see text]]o on neuronal excitability and seizure activity.

scholarly journals Chronic in vivo optogenetic stimulation modulates neuronal excitability, spine morphology and Hebbian plasticity in the mouse hippocampus

2018 ◽  
Author(s):  
Thiago C. Moulin ◽  
Lyvia L. Petiz ◽  
Danielle Rayêe ◽  
Jessica Winne ◽  
Roberto G. Maia ◽  
...  
Keyword(s):  
Neuronal Excitability ◽  
Pyramidal Neurons ◽  
Ex Vivo ◽  
Morphological Changes ◽  
Spine Density ◽  
Optogenetic Stimulation ◽  
Light Pulses ◽  
Ca1 Region ◽  
Hebbian Plasticity

AbstractProlonged increases in excitation can trigger cell-wide homeostatic responses in neurons, altering membrane channels, promoting morphological changes and ultimately reducing synaptic weights. However, how synaptic downscaling interacts with classical forms of Hebbian plasticity is still unclear. In this study, we investigated whether chronic optogenetic stimulation of hippocampus CA1 pyramidal neurons in freely-moving mice could (a) cause morphological changes reminiscent of homeostatic scaling, (b) modulate synaptic currents that might compensate for chronic excitation, and (c) lead to alterations in Hebbian plasticity. After 24 h of stimulation with 15-ms blue light pulses every 90 s, dendritic spine density and area were reduced in the CA1 region of mice expressing channelrhodopsin-2 (ChR2) when compared to controls. This protocol also reduced the amplitude of mEPSCs for both the AMPA and NMDA components in ex vivo slices obtained from ChR2-expressing mice immediately after the end of stimulation. Lastly, chronic stimulation impaired the induction of LTP and facilitated that of LTD in these slices. Our results indicate that neuronal responses to prolonged network excitation can modulate subsequent Hebbian plasticity in the hippocampus.

Effect of dialkyl- [2-(1-oxa-3,4,9-triaza-fluoren-2-yl-methoxy)ethyl] amines on biogenic amines: new potential antidepressants

2012 ◽  
Vol 90 (12) ◽  
pp. 1585-1590
Author(s):  
Akena Venkatesham ◽  
J. Venkateshwar Rao ◽  
K. Vijay Kumar ◽  
M. Sarangapani ◽  
Krishna Devarakonda
Keyword(s):  
Biogenic Amines ◽  
Forced Swim Test ◽  
Chronic Administration ◽  
Antidepressant Activity ◽  
Tail Suspension Test ◽  
Control Group ◽  
Stress Model ◽  
Chronic Unpredictable Stress ◽  
The Brain

A thorough survey of the literature has revealed that indole derivatives have shown various central nervous system activities. This study aims to evaluate the antidepressant activity of the newly synthesized dialkyl- [2-(1-oxa-3,4,9-triaza-fluoren-2-yl-methoxy)ethyl] amines and their effect on biogenic amines. In this study, the synthesized compounds were assessed by in-vivo antidepressant models, by forced swim test and tail suspension test in mice and effect of synthesized compounds on biogenic amines in brain in a chronic unpredictable stress model. The test compounds have demonstrated significant (P < 0.05) reduced immobility duration in mice when compared with the control group animals. The reduced immobility displayed by mice indicates potential antidepressant activity. In this study, chronic unpredictable stress led to decreased monoamine levels in the cortex and hippocampus regions of the brain. With chronic administration of the investigated compounds there is an increased in monoamines in the brain, in the chronic unpredictable stress model. Decreased levels of monoamines induced by the chronic unpredictable stress induced model of depression, were normalized by treatment with the test compounds, which indicates potential antidepressant activity.

scholarly journals Cav2.3 (R-Type) Calcium Channels are Critical for Mediating Anticonvulsive and Neuroprotective Properties of Lamotrigine In Vivo

2017 ◽  
Vol 44 (3) ◽  
pp. 935-947 ◽  
Author(s):  
Maxine Dibué-Adjei ◽  
Marcel A. Kamp ◽  
Serdar Alpdogan ◽  
Etienne E. Tevoufouet ◽  
Wolfram F. Neiss ◽  
...  
Keyword(s):  
Pyramidal Neurons ◽  
Seizure Activity ◽  
Calcium Currents ◽  
Ca1 Neurons ◽  
Ca1 Region ◽  
Anticonvulsive Effect ◽  
Ictal Activity ◽  
Deficient Mice

Background/Aims: Lamotrigine (LTG) is a popular modern antiepileptic drug (AED), however, its mechanism of action has yet to be fully understood, as it is known to modulate many members of several ion channel families. In heterologous systems, LTG inhibits Cav2.3 (R-type) calcium currents, which contribute to kainic-acid- (KA) induced epilepsy in vivo. To gain insight into the role of R-type currents in LTG drug action in vivo, we compared the effects of LTG to topiramate and lacosamide in Cav2.3-deficient mice and controls on KA-induced seizures. Methods: Behavioral seizure rating and quantitative electrocorticography were performed after injection of 20 mg/kg [and 30 mg/kg] KA. One hour before KA injection, mice were pretreated with either 30 mg/kg LTG, 50 mg/kg topiramate (TPM) or 30 mg/kg lacosamide (LSM). Results: Ablation of Cav2.3 reduced total seizure scores by 28.6% (p=0.0012) and pretreatment with LTG reduced seizure activity of control mice by 23.2% (p=0.02). In Cav2.3-deficient mice LTG pretreatment increased seizure activity by 22.1% (p=0.018) and increased the percentage of degenerated CA1 pyramidal neurons (p=0.02). All three tested AEDs reduced seizure activity in control mice, however only the non-calcium channel modulating AED, LSM had an anticonvulsive effect in Cav2.3-deficient mice. Furthermore LTG altered electrocorticographic parameters differently in the two genotypes, decreasing relative power of ictal spikes in control mice compared to Cav2.3-defcient mice. Conclusion: These findings give first in vivo evidence for an essential role for Cav2.3 in LTG pharmacology and shed light on a paradoxical effect of LTG in their absence. Furthermore, LTG appears to promote ictal activity in Cav2.3-deficient mice resulting in increased neurotoxicity in the CA1 region. This paradoxical mechanism, possibly reflecting rebound hyperexcitation of pyramidal CA1 neurons after increased inhibition, may be key in understanding LTG-induced seizure aggravation, observed in clinical practice.

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