scholarly journals Down-regulation of habenular calcium-dependent secretion activator 2 induces despair-like behavior

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hyeijung Yoo ◽  
Soo Hyun Yang ◽  
Jin Yong Kim ◽  
Esther Yang ◽  
Hyung Sun Park ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Learned Helplessness ◽  
Down Regulation ◽  
Depressive Behavior ◽  
Interpeduncular Nucleus ◽  
Calcium Dependent ◽  
Neuropeptide Secretion ◽  
Medial Habenula ◽  
Model Mouse

AbstractCalcium-dependent secretion activator 2 (CAPS2) regulates the trafficking and exocytosis of neuropeptide-containing dense-core vesicles (DCVs). CAPS2 is prominently expressed in the medial habenula (MHb), which is related to depressive behavior; however, how MHb neurons cause depressive symptoms and the role of CAPS2 remains unclear. We hypothesized that dysfunction of MHb CAPS neurons might cause defects in neuropeptide secretion and the activity of monoaminergic centers, resulting in depressive-like behaviors. In this study, we examined (1) CAPS2 expression in the habenula of depression animal models and major depressive disorder patients and (2) the effects of down-regulation of MHb CAPS2 on the animal behaviors, synaptic transmission in the interpeduncular nucleus (IPN), and neuronal activity of monoamine centers. Habenular CAPS2 expression was decreased in the rat chronic restraint stress model, mouse learned helplessness model, and showed tendency to decrease in depression patients who died by suicide. Knockdown of CAPS2 in the mouse habenula evoked despair-like behavior and a reduction of the release of DCVs in the IPN. Neuronal activity of IPN and monoaminergic centers was also reduced. These results implicate MHb CAPS2 as playing a pivotal role in depressive behavior through the regulation of neuropeptide secretion of the MHb-IPN pathway and the activity of monoaminergic centers.

Biochemical hypotheses on antidepressant drugs: a guide for clinicians or a toy for pharmacologists?

1988 ◽  
Vol 18 (2) ◽  
pp. 287-304 ◽  
Author(s):  
Silvio Garattini ◽  
Rosario Samanin
Keyword(s):  
Learned Helplessness ◽  
Antidepressant Drugs ◽  
Antidepressant Activity ◽  
Experimental Models ◽  
Clinical Activity ◽  
Repeated Treatment ◽  
Down Regulation ◽  
General Validity ◽  
Monoamine Uptake

SynopsisThe development of knowledge about the mechanism of action of tricyclic and the so-called ‘atypical’ antidepressants (AD) is reviewed. The discovery of clinically active antidepressants with little or no effect on noradrenaline or serotonin uptake has disproved the widely accepted concept that inhibition of monoamine uptake is a prerequisite for antidepressant activity. Another serious objection to this hypothesis is that blockade of monoamine uptake occurs in a matter of minutes after administration while 2–3 weeks of repeated treatment are necessary for the clinical AD effect. Nevertheless, the effect of repeated treatment with AD is compatible with the hypothesis that changes in central monoamine transmission are involved in the clinical activity of these drugs. Major changes in monoamine function after repeated treatment with AD include: desensitization and reduced density of noradrenaline receptors coupled to the adenylcyclase system, opposite changes in the sensitivity of α1 (increased) and α2-adrenoreceptors (decreased), down regulation of serotonin2 receptors and complex changes in the behavioural and electrophysiological responsiveness to serotonin agonists, subsensitivity of presynaptic dopamine receptors and enhanced activity of the mesolimbic dopamine system, decreased and increased density of GABA-A and GABA-B receptors respectively and down regulation of [3H]benzodiazepine binding.It remains to be clarified whether some of these changes have larger roles than others or whether they all contribute to the AD activity. An important role of dopamine in the activity of AD drugs is suggested by findings in the forced swimming test, whereas both catecholamines seem to be involved in the attenuation of escape deficit provoked by inescapable shock (learned helplessness). No clear evidence for a role of serotonin (with the possible exception of serotonin1A receptors) or GABA has been obtained in these experimental models of depression. The general validity of these findings obviously rests on the assumption that these models represent significant aspects of human depression.

scholarly journals GABAB receptor auxiliary subunits modulate Cav2.3-mediated release from medial habenula terminals

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Pradeep Bhandari ◽  
David Vandael ◽  
Diego Fernández-Fernández ◽  
Thorsten Fritzius ◽  
David Kleindienst ◽  
...  
Keyword(s):  
Active Zone ◽  
Synaptic Connection ◽  
Gabab Receptor ◽  
Interpeduncular Nucleus ◽  
Medial Habenula ◽  
Tetramerization Domain ◽  
Genetic Deletion ◽  
And Function ◽  
Deficient Mice

The synaptic connection from medial habenula (MHb) to interpeduncular nucleus (IPN) is critical for emotion-related behaviors, and uniquely expresses R-type Ca2+ channels (Cav2.3) and auxiliary GABAB receptor (GBR) subunits, the K+-channel tetramerization domain-containing proteins (KCTDs). Activation of GBRs facilitates or inhibits transmitter release from MHb terminals depending on the IPN subnucleus, but the role of KCTDs is unknown. We therefore examined the localization and function of Cav2.3, GBRs, and KCTDs in this pathway in mice. We show in heterologous cells that KCTD8 and KCTD12b directly bind to Cav2.3 and that KCTD8 potentiates Cav2.3 currents in the absence of GBRs. In the rostral IPN, KCTD8, KCTD12b and Cav2.3 co-localize at the presynaptic active zone. Genetic deletion indicated a bidirectional modulation of Cav2.3-mediated release by these KCTDs with a compensatory increase of KCTD8 in the active zone in KCTD12b-deficient mice. The interaction of Cav2.3 with KCTDs therefore scales synaptic strength independent of GBR activation.

Hippocampal ripples down-regulate synapses

Science ◽  
2018 ◽  
Vol 359 (6383) ◽  
pp. 1524-1527 ◽  
Author(s):  
Hiroaki Norimoto ◽  
Kenichi Makino ◽  
Mengxuan Gao ◽  
Yu Shikano ◽  
Kazuki Okamoto ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Neuronal Activity ◽  
Slow Wave ◽  
Down Regulation ◽  
Sharp Wave ◽  
Specific Effects ◽  
Aspartate Receptor ◽  
Specific Input ◽  
Wave States

The specific effects of sleep on synaptic plasticity remain unclear. We report that mouse hippocampal sharp-wave ripple oscillations serve as intrinsic events that trigger long-lasting synaptic depression. Silencing of sharp-wave ripples during slow-wave states prevented the spontaneous down-regulation of net synaptic weights and impaired the learning of new memories. The synaptic down-regulation was dependent on the N-methyl-d-aspartate receptor and selective for a specific input pathway. Thus, our findings are consistent with the role of slow-wave states in refining memory engrams by reducing recent memory-irrelevant neuronal activity and suggest a previously unrecognized function for sharp-wave ripples.

Effect of Annexins Translocated in Extracellular Vesicles on Tumorigenesis

2020 ◽  
Vol 20 ◽  
Author(s):  
Qionghui Wu ◽  
Haidong Wei ◽  
Wenbo Meng ◽  
Xiaodong Xie ◽  
Zhenchang Zhang ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Extracellular Vesicles ◽  
Immune Cell ◽  
Epithelial Mesenchymal Transition ◽  
Main Role ◽  
Tumor Cell Adhesion ◽  
Mesenchymal Transition ◽  
Calcium Dependent ◽  
Tumor Neovascularization

: Annexin, a calcium-dependent phospholipid binding protein, can affect tumor cell adhesion, proliferation, apoptosis, invasion and metastasis, as well as tumor neovascularization in different ways. Recent studies have shown that annexin exists not only as an intracellular protein in tumor cells, but also in different ways to be secret outside the cell as a “crosstalk” tool for tumor cells and tumor microenvironment, thus playing an important role in the development of tumors, such as participating in epithelial-mesenchymal transition, regulating immune cell behavior, promoting neovascularization and so on. The mechanism of annexin secretion in the form of extracellular vesicles and its specific role is still unclear. This paper summarizes the main role of annexin secreted into the extracellular space in the form of extracellular vesicles in tumorigenesis and drug resistance and analyzes its possible mechanism.

scholarly journals A CACNA1A variant associated with trigeminal neuralgia alters the gating of Cav2.1 channels

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Eder Gambeta ◽  
Maria A. Gandini ◽  
Ivana A. Souza ◽  
Laurent Ferron ◽  
Gerald W. Zamponi
Keyword(s):  
Trigeminal Neuralgia ◽  
Missense Mutation ◽  
Neurotransmitter Release ◽  
Trigeminal System ◽  
Wild Type ◽  
Calcium Dependent ◽  
Whole Cell Patch Clamp ◽  
C Terminus ◽  
Dependent Inactivation

AbstractA novel missense mutation in the CACNA1A gene that encodes the pore forming α1 subunit of the CaV2.1 voltage-gated calcium channel was identified in a patient with trigeminal neuralgia. This mutation leads to a substitution of proline 2455 by histidine (P2455H) in the distal C-terminus region of the channel. Due to the well characterized role of this channel in neurotransmitter release, our aim was to characterize the biophysical properties of the P2455H variant in heterologously expressed CaV2.1 channels. Whole-cell patch clamp recordings of wild type and mutant CaV2.1 channels expressed in tsA-201 cells reveal that the mutation mediates a depolarizing shift in the voltage-dependence of activation and inactivation. Moreover, the P2455H mutant strongly reduced calcium-dependent inactivation of the channel that is consistent with an overall gain of function. Hence, the P2455H CaV2.1 missense mutation alters the gating properties of the channel, suggesting that associated changes in CaV2.1-dependent synaptic communication in the trigeminal system may contribute to the development of trigeminal neuralgia.

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