The central nervous system is a well-known steroidogenic tissue producing, among others, cholesterol metabolites such as neuroactive steroids, oxysterols and steroid hormones. It is well known that these endogenous molecules affect several receptor classes, including ionotropic GABAergic and NMDA glutamatergic receptors in neurons. It has been shown that also ionotropic purinergic (P2X) receptors are cholesterol metabolites' targets. Among P2X receptors, purinergic P2X4 and P2X7 receptors are expressed in microglia, the innate immune cells involved in the brain inflammatory response. In this study, we explore the ionotropic purinergic receptors modulation by cholesterol metabolites in microglia. Patch-clamp experiments were performed in BV2 cells, a murine microglia cell line, to evaluate effects of cholesterol metabolites using micro- and nanomolar concentrations. About P2X4 receptor, we found that testosterone butyrate (20 μM and 200 nM) and allopregnanolone (10 μM and 100 nM) both potentiated its current, while neither 25-hydroxycholesterol (10 μM and 100 nM) nor 17β-estradiol (1 μM) showed any effects. On the other hand, P2X7 receptor current was potentiated by allopregnanolone (10 μM) and 25-hydroxycholesterol (10 μM and 100 nM). Taken together, our data show that modulation of either P2X4 and P2X7 current is affected differently by cholesterol metabolites, suggesting a structure-activity relationship among these players. Identifying the possible link between purinergic transmission, microglia and cholesterol metabolites will allow to define new targets for drug development to treat neuroinflammation.
- Klíčová slova
- Microglia, Neuroactive steroids, Neuroinflammation, Oxysterols, P2X4 receptor, P2X7 receptor,
- MeSH
- buněčné linie MeSH
- mikroglie * metabolismus MeSH
- pregnanolon * metabolismus MeSH
- purinergní receptory P2X4 * metabolismus MeSH
- testosteron * metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- pregnanolon * MeSH
- purinergní receptory P2X4 * MeSH
- testosteron * MeSH
The hippocampus (HPC) is essential for navigation and memory, tracking environmental continuity and change, including navigation relative to moving targets. CA1 ensembles expressing immediate-early gene (IEG) Arc and Homer1a RNA are contextually specific. While IEG expression correlates with HPC-dependent task demands, the effects of behavioral demands on IEG-expressing ensembles remain unclear. In three experiments, we investigated the effects of context switch, sustained presence, and task demands on dorso-proximal CA1 IEG+ ensembles in rats. Experiment 1 showed that the size of IEG+ (Arc, Homer1a RNA) ensembles dropped to baseline during uninterrupted 30-min exploration, reflecting familiarization, unless a context switch was present. Context-specificity of the ensembles depended on both environment identity and timing of the context switch. Experiment 2 found no effect of HPC-dependent mobile robot avoidance or HPC-independent avoidance of a stationary robot on IEG+ ensembles beyond mere exploration. Experiment 3 replicated these findings for c-Fos protein. The data suggest that IEG+ ensembles are driven by a context switch and shrink over time during sustained presence in the same environment. We found no evidence of task demands or their change affecting the size, stability over time, or task-specificity of IEG+ ensembles. These results shed light on the temporal dynamics of CA1 IEG+ ensembles, and their control by contextual and behavioral factors.
- Klíčová slova
- Arc/Homer1a catFISH, Behavioral episode, C-Fos, Ensemble stability, Moving/stationary robot avoidance, RNA,
- MeSH
- chování zvířat fyziologie MeSH
- cytoskeletální proteiny genetika metabolismus MeSH
- hipokampální oblast CA1 * metabolismus fyziologie MeSH
- Homer scaffold proteiny * metabolismus genetika MeSH
- krysa rodu Rattus MeSH
- okamžité časné geny * fyziologie MeSH
- potkani Long-Evans * MeSH
- proteiny nervové tkáně genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- activity regulated cytoskeletal-associated protein MeSH Prohlížeč
- cytoskeletální proteiny MeSH
- Homer scaffold proteiny * MeSH
- Homer1 protein, rat MeSH Prohlížeč
- proteiny nervové tkáně MeSH
Permeability is an important molecular property in drug discovery, as it co-determines pharmacokinetics whenever a drug crosses the phospholipid bilayer, e.g., into the cell, in the gastrointestinal tract, or across the blood-brain barrier. Many methods for the determination of permeability have been developed, including cell line assays (CACO-2 and MDCK), cell-free model systems like parallel artificial membrane permeability assay (PAMPA) mimicking, e.g., gastrointestinal epithelia or the skin, as well as the black lipid membrane (BLM) and submicrometer liposomes. Furthermore, many in silico approaches have been developed for permeability prediction: meta-analysis of publicly available databases for permeability data (MolMeDB and ChEMBL) was performed to establish their usability. Four experimental and two computational methods were evaluated. It was shown that repeatability of the reported permeability measurement is not great even for the same method. For the PAMPA method, two different permeabilities are reported: intrinsic and apparent. They can vary in degrees of magnitude; thus, we suggest being extra cautious using literature data on permeability. When we compared data for the same molecules using different methods, the best agreement was between cell-based methods and between BLM and computational methods. Existence of unstirred water layer (UWL) permeability limits the data agreement between cell-based methods (and apparent PAMPA) with data that are not limited by UWL permeability (computational methods, BLM, intrinsic PAMPA). Therefore, different methods have different limitations. Cell-based methods provide results only in a small range of permeabilities (-8 to -4 in cm/s), and computational methods can predict a wider range of permeabilities beyond physical limitations, but their precision is therefore limited. BLM with liposomes can be used for both fast and slow permeating molecules, but its usage is more complicated than standard transwell techniques. To sum up, when working with in-house measured or published permeability data, we recommend caution in interpreting and combining them.
- Klíčová slova
- BLM, CACO-2, COSMOperm, MDCK, MolMeDB, PAMPA, PerMM, liposome, membrane, permeability,
- MeSH
- buňky MDCK MeSH
- Caco-2 buňky MeSH
- hematoencefalická bariéra metabolismus MeSH
- lidé MeSH
- liposomy * chemie MeSH
- membrány umělé MeSH
- permeabilita buněčné membrány fyziologie MeSH
- permeabilita * MeSH
- psi MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- psi MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- Názvy látek
- liposomy * MeSH
- membrány umělé MeSH
BACKGROUND AND OBJECTIVES: En bloc sacrectomy is associated with sacral root transection causing loss of urinary bladder, rectum, and sexual function. The aim of the study was to determine the position of the pudendal branches (sensorimotor) and pelvic splanchnic nerves (parasympathetic) on the sacral roots relative to the sacrum, and the minimal and maximal defects in the sacral roots that can be reconstructed by grafting after various types of sacrectomy. METHODS: Five cadaveric pelves were dissected bilaterally. The lengths and widths of the S1-S4 roots and their branches were measured. Then, the minimal and maximal defects between the proximal and distal stumps of the sacrificed roots were measured following 3 models of sacrectomy (below S2, below S1, and total sacrectomy). RESULTS: The mean distance of the splanchnic nerves from the S2 and S3 anterior sacral foramina was 17.7 ± 7.3 and 23.6 ± 11.1 mm, respectively, and the mean distance of the pudendal S2 and S3 branches was 36.8 ± 13.7 and 30.2 ± 10.8 mm, respectively. The mean widths of the S2 and S3 roots were 9.3 ± 1.9 and 5.4 ± 1.2 mm, respectively. The mean maximal defects in S2 and S3 roots after various types of sacrectomies were between 61.8 ± 16.3 and 100.7 ± 14.3 mm and between 62.7 ± 20.2 and 84.7 ± 25.1 mm, respectively. There were no statistically significant differences between sides or sexes for all obtained measurements. CONCLUSION: The reconstruction of the S2-S3 roots is anatomically feasible after partial or total sacrectomies in which the resection of the soft tissue does not extend further than approximately 1.5 to 2 cm ventrally from the sacrum.
- MeSH
- křížová kost * chirurgie anatomie a histologie inervace MeSH
- lidé středního věku MeSH
- lidé MeSH
- míšní kořeny * anatomie a histologie chirurgie MeSH
- mrtvola * MeSH
- senioři MeSH
- splanchnické nervy anatomie a histologie chirurgie MeSH
- zákroky plastické chirurgie metody MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Pikeperch (Sander Lucioperca) belongs to main predatory fish species in freshwater bodies throughout Europe playing the key role by reducing planktivorous fish abundance. Two size classes of the young-of-the-year (YOY) pikeperch are known in Europe and North America. Our long-term fish survey elucidates late-summer size distribution of YOY pikeperch in the Lipno Reservoir (Czechia) and recognizes two distinct subcohorts: smaller pelagic planktivores heavily outnumber larger demersal piscivores. To explore molecular mechanisms accompanying the switch from planktivory to piscivory, we compared brain transcriptomes of both subcohorts and identified 148 differentially transcribed genes. The pathway enrichment analyses identified the piscivorous phase to be associated with genes involved in collagen and extracellular matrix generation with numerous Gene Ontology (GO), while the planktivorous phase was associated with genes for non-muscle-myosins (NMM) with less GO terms. Transcripts further upregulated in planktivores from the periphery of the NMM network were Pmchl, Pomcl, and Pyyb, all involved also in appetite control and producing (an)orexigenic neuropeptides. Noncoding RNAs were upregulated in transcriptomes of planktivores including three transcripts of snoRNA U85. Thirty genes mostly functionally unrelated to those differentially transcribed were alternatively spliced between the subcohorts. Our results indicate planktivores as potentially driven by voracity to initiate the switch to piscivory, while piscivores undergo a dynamic brain development. We propose a spatiotemporal spreading of juvenile development over a longer period and larger spatial scales through developmental plasticity as an adaptation to exploiting all types of resources and decreasing the intraspecific competition.
- Klíčová slova
- (Sander (Stizostedion) lucioperca), brain transcriptome, cannibalism, developmental plasticity, heterochrony, snoRNA,
- MeSH
- alternativní sestřih * MeSH
- genetická transkripce MeSH
- mozek * metabolismus MeSH
- nekódující RNA genetika metabolismus MeSH
- okounovití genetika fyziologie MeSH
- regulace genové exprese fyziologie MeSH
- stravovací zvyklosti MeSH
- transkriptom * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- nekódující RNA MeSH
The serotonergic psychedelics psilocybin, LSD and DMT hold great promise for the development of new treatments for psychiatric conditions such as major depressive disorder, addiction and end-of-life anxiety. Previous studies in both animals and humans have confirmed the effects of these drugs on neuronal activity and plasticity. However, the understanding of the mechanisms of action of these substances is limited. Here we show rapid effects of psychedelics on presynaptic properties, using live cell imaging at the level of single synapses in primary rat cortical neurons. Using the genetically encoded reporter of synaptic vesicle fusion synaptopHluorin, we detected a reduced fraction of synaptic vesicles that fused in response to mild or strong electrical stimulation 3-30 min after application of serotonergic psychedelics. These effects were transient and no longer present 24 h after treatment. While DMT only reduced the total recycling pool, LSD and psilocin also reduced the size of the readily releasable vesicle pool. Imaging with the sensors for glutamate, iGluSnFR, and presynaptic calcium, synGCaMP6, showed that while psilocin and DMT increased evoked glutamate release, LSD and psilocin reduced evoked presynaptic calcium levels. Interestingly, psilocin also affected short-term plasticity leading to a depression of responses to paired stimuli. The rapid and drug-specific modulation of glutamatergic neurotransmission described in this study may contribute to distinct anxiolytic and antidepressant properties of serotonergic psychedelics.
- Klíčová slova
- 5‐HT2A, fluorescent sensors, neurotransmitter release, presynaptic, short‐term plasticity, synaptic vesicles,
- MeSH
- halucinogeny * farmakologie MeSH
- krysa rodu Rattus MeSH
- kultivované buňky MeSH
- kyselina glutamová * metabolismus MeSH
- LSD farmakologie MeSH
- mozková kůra * účinky léků metabolismus cytologie MeSH
- neurony * účinky léků metabolismus MeSH
- potkani Sprague-Dawley MeSH
- psilocybin farmakologie MeSH
- serotoninové látky farmakologie MeSH
- synaptické vezikuly účinky léků metabolismus MeSH
- tryptaminy farmakologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- halucinogeny * MeSH
- kyselina glutamová * MeSH
- LSD MeSH
- psilocybin MeSH
- serotoninové látky MeSH
- tryptaminy MeSH
During GABAergic synaptic transmission, G protein-coupled GABAB receptors (GBRs) activate K+ channels that prolong the duration of inhibitory postsynaptic potentials (IPSPs). We now show that KCTD16, an auxiliary GBR subunit, anchors hyperpolarization-activated cyclic nucleotide-gated (HCN) channels containing HCN2/HCN3 subunits to GBRs. In dopamine neurons of the VTA (DAVTA neurons), this interaction facilitates activation of HCN channels via hyperpolarization during IPSPs, counteracting the GBR-mediated late phase of these IPSPs. Consequently, disruption of the GBR/HCN complex in KCTD16-/- mice leads to prolonged optogenetic inhibition of DAVTA neuron firing. KCTD16-/- mice exhibit increased anxiety-like behavior in response to stress - a behavior replicated by CRISPR/Cas9-mediated KCTD16 ablation in DAVTA neurons or by intra-VTA infusion of an HCN antagonist in wild-type mice. Our findings support that the retention of HCN channels at GABAergic synapses by GBRs in DAVTA neurons provides a negative feedback mechanism that restricts IPSP duration and mitigates the development of anxiety.
- Klíčová slova
- GABA-A, GABA-B, HCN2, Hyperpolarization-activated cyclic nucleotide-gated channels, Late IPSP, Optogenetic inhibition, Slow IPSP,
- MeSH
- dopaminergní neurony * metabolismus MeSH
- hyperpolarizační iontové kanály řízené cyklickými nukleotidy * metabolismus genetika MeSH
- inhibiční postsynaptické potenciály fyziologie účinky léků MeSH
- myši inbrední C57BL MeSH
- myši knockoutované MeSH
- myši MeSH
- receptory GABA-B * metabolismus MeSH
- tegmentum mesencephali - area ventralis * metabolismus MeSH
- úzkost * metabolismus MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- hyperpolarizační iontové kanály řízené cyklickými nukleotidy * MeSH
- receptory GABA-B * MeSH
PURPOSE: The aim of this study was to develop a simple, robust, and easy-to-use calibration procedure for correcting misalignments in rosette MRI k-space sampling, with the objective of producing images with minimal artifacts. METHODS: Quick automatic calibration scans were proposed for the beginning of the measurement to collect information on the time course of the rosette acquisition trajectory. A two-parameter model was devised to match the measured time-varying readout gradient delays and approximate the actual rosette sampling trajectory. The proposed calibration approach was implemented, and performance assessment was conducted on both phantoms and human subjects. RESULTS: The fidelity of phantom and in vivo images exhibited significant improvement compared with uncorrected rosette data. The two-parameter calibration approach also demonstrated enhanced precision and reliability, as evidenced by quantitative T 2 * $$ {\mathrm{T}}_2^{\ast } $$ relaxometry analyses. CONCLUSION: Adequate correction of data sampling is a crucial step in rosette MRI. The presented experimental results underscore the robustness, ease of implementation, and suitability for routine experimental use of the proposed two-parameter rosette trajectory calibration approach.
- Klíčová slova
- gradient imperfections, k‐space misalignment, rosette trajectory, trajectory estimation,
- MeSH
- algoritmy * MeSH
- artefakty * MeSH
- fantomy radiodiagnostické * MeSH
- kalibrace MeSH
- lidé MeSH
- magnetická rezonanční tomografie * metody MeSH
- mozek diagnostické zobrazování MeSH
- počítačové zpracování obrazu * metody MeSH
- reprodukovatelnost výsledků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Cerebellar extinction lesions can manifest themselves with cerebellar motor and cerebellar cognitive affective syndromes. For investigation of the functions of the cerebellum and the pathogenesis of cerebellar diseases, particularly hereditary neurodegenerative cerebellar ataxias, various cerebellar mutant mice are used. The Lurcher mouse is a model of selective olivocerebellar degeneration with early onset and rapid progress. These mice show both motor deficits as well as cognitive and behavioral changes i.e., pathological phenotype in the functional domains affected in cerebellar patients. Therefore, Lurcher mice might be considered as a tool to investigate the mechanisms of functional impairments caused by cerebellar degenerative diseases. There are, however, limitations due to the particular features of the neurodegenerative process and a lack of possibilities to examine some processes in mice. The main advantage of Lurcher mice would be the expected absence of significant neuropathologies outside the olivocerebellar system that modify the complex behavioral phenotype in less selective models. However, detailed examinations and further thorough validation of the model are needed to verify this assumption.
- Klíčová slova
- Ataxia, Cerebellar Cognitive Affective Syndrome, Cerebellum, Lurcher Mouse, Validity,
- MeSH
- cerebelární ataxie genetika patofyziologie patologie MeSH
- lidé MeSH
- modely nemocí na zvířatech * MeSH
- mozeček patologie patofyziologie MeSH
- myši - mutanty neurologické MeSH
- myši MeSH
- nemoci mozečku * patologie patofyziologie genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
The human mind, trying to perceive events coherently, creates the illusion of continuous time passage. Empirical evidence suggests distortions in subjectively perceived time flow associated with well-studied neural responses to sensory stimuli. This study aimed to investigate whether visually uncomfortable patterns, causing exceptionally strong brain activation, affect short time estimates and whether these estimates vary based on the overall reported sensory sensitivity and cortical excitability of individuals. Two experiments in virtual reality testing our assumptions at different levels of complexity of timed stimuli provided initial insight into the studied processes in highly controlled and realistic conditions. Data analysis results did not support our hypotheses, but showed that subjectively most visually uncomfortable simple patterns, i.e., achromatic gratings, cause more variable temporal judgments. Supposedly, this inaccuracy depends on the currently perceived visual comfort and thus the current visual system sensitivity, which cannot be satisfactorily derived from trait-based measures. The exploration of the effect of complex stimuli, i.e., virtual exteriors, suggested that their visual comfort does not affect time perception at all. Biological sex was an important variable across experiments, as males experienced temporal compression of stimuli compared to females. Neuroimaging research is needed for a deeper investigation of the origin of these results.Protocol registration: The Stage 1 manuscript associated with this Registered Report was in-principle accepted on 4 March 2024 prior to data collection for hypothesis testing. The accepted version of the manuscript can be found in the publicly available OSF repository at https://doi.org/ https://doi.org/10.17605/OSF.IO/K3YZE .
- MeSH
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mozek fyziologie diagnostické zobrazování MeSH
- světelná stimulace metody MeSH
- virtuální realita MeSH
- vnímání času * fyziologie MeSH
- zraková percepce * fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH