Electrophysiological Analysis Research Articles

Sorted sample- wavelet feature clustering based on the range for classification of multiple nutrient deficiencies in tomato plants

The phenomenon of physiological change in plants hyperpolarizes membrane potentials showing a significant change in electrophysiology. For plants to survive, develop, and reproduce, the proper ratio of nutrients is required. Malnourished plants exhibit unfavorable changes in their physiology. Nutrient deficiencies are one of the primary abiotic stresses occurred in plants which are commonly identified and classified through various hyperspectral imaging, and pattern recognition methods. In contrast to image-based methods, in this paper, the electrophysiological signal data of tomato plants in multiple nutrient deficiency states are classified. These electrical signals of tomato plants are acquired in healthy and in deficient states of calcium (Ca), manganese (Mn), nitrogen (N), and iron (Fe). The features are extracted by 7-level orthogonal wavelet decomposition using four different wavelets Daubechies (Db), Coiflet (Cf), Symlet (Sym), and Discrete Meyer (Dm). A novel range-based sorted sample clustering method is proposed to boost classification performance. Class assignment is performed in two modes homogeneous and non-homogeneous, where multi-class classification in non-homogeneous class assignment attained 99.4 % accuracy and in homogeneous class assignment a highest accuracy of 96.8 % is attained using the KNN classifier. Identifying nutrient deficiencies through electrophysiological signal analysis dominated the detection through imaging techniques, impacting a drastic change in crop protection practices.

A Comprehensive Protocol for Efficient Differentiation of Human NPCs into Electrically Competent Neurons

BackgroundThe study of neurons is fundamental to unraveling the complexities of the nervous system. Primary neuronal cultures from rodents have long been a cornerstone of experimental studies, yet limitations related to their non-human nature and ethical concerns have prompted the development of alternatives. In recent years, the derivation of neurons from human-induced pluripotent stem cells (hiPSCs) has emerged as a powerful option, offering a scalable source of cells for diverse applications. Neural progenitor cells (NPCs) derived from hiPSCs can be efficiently differentiated into functional neurons, providing a platform to study human neural physiology and pathology in vitro. However, challenges persist in achieving consistent and reproducible outcomes across experimental settings. Comparison with existing methodsOur aim is to provide a step-by-step methodological protocol, augmenting existing procedures with additional instructions and parameters, to guide researchers in achieving reproducible results. Methods and resultsWe outline procedures for the differentiation of hiPSC-derived NPCs into electrically competent neurons, encompassing initial cell density, morphology, maintenance, and differentiation. We also describe the analysis of specific markers for assessing neuronal phenotype, along with electrophysiological analysis to evaluate biophysical properties of neuronal excitability. Additionally, we conduct a comparative analysis of three different chemical methods—KCl, N-methyl-D-aspartate (NMDA), and bicuculline—to induce neuronal depolarization and assess their effects on the induction of both fast and slow post-translational, transcriptional, and post-transcriptional responses. ConclusionOur protocol provides clear instructions for generating reliable human neuronal cultures with defined electrophysiological properties to investigate neuronal differentiation and model diseases in vitro.

Celastrol exerts antiarrhythmic effects in chronic heart failure via NLRP3/Caspase-1/IL-1β signaling pathway

ObjectivesCelastrol has widespread therapeutic applications in various pathological conditions, including chronic inflammation. Previous studies have demonstrated the potent cardioprotective effects of celastrol. Nevertheless, limited attention has been given to its potential in reducing ventricular arrhythmias (VAs) following myocardial infarction (MI). Hence, this study aimed to elucidate the potential mechanisms underlying the regulatory effects of celastrol on VAs and cardiac electrophysiological parameters in rats after MI. MethodsSprague-Dawley rats were divided at random: the sham, MI, and MI + celastrol groups. The left coronary artery was occluded in the MI and MI + Cel groups. Electrocardiogram, heart rate variability (HRV), ventricular electrophysiological parameters analysis, histology staining of ventricles, Enzyme-linked immunosorbent assay (ELISA), western blotting and Quantitative real-time polymerase chain reaction (qRT-PCR) were performed to elucidate the underlying mechanism of celastrol. Besides, H9c2 cells were subjected to hypoxic conditions to create an in vitro model of MI and then treated with celastrol for 24 hours. Nigericin was used to activate the NLRP3 inflammasome. ResultsCompared with that MI group, cardiac electrophysiology instability was significantly alleviated in the MI + celastrol group. Additionally, celastrol improved HRV, upregulated the levels of Cx43, Kv.4.2, Kv4.3 and Cav1.2, mitigated myocardial fibrosis, and inhibited the NLRP3 inflammasome pathway. In vitro conditions also supported the regulatory effects of celastrol on the NLRP3 inflammasome pathway. ConclusionsCelastrol could alleviate the adverse effects of VAs after MI partially by promoting autonomic nerve remodeling, ventricular electrical reconstruction and ion channel remodeling, and alleviating ventricular fibrosis and inflammatory responses partly by through inhibiting the NLRP3/Caspase-1/IL-1β pathway.

Synthetic Alfalfa Infusion Odour Attracts Gravid Culex quinquefasciatus Under Laboratory Conditions.

Gravid culicine mosquitoes rely on olfactory cues for selecting breeding sites containing organic detritus. While this capacity of the mosquitoes is used for surveillance and control, the current methodology is unwieldy, unreliable and expensive in time and labour. This study evaluated the dose-dependent attraction and oviposition response of gravid Culex quinquefasciatus to alfalfa infusions. Through combined chemical and electrophysiological analyses, bioactive volatile organic compounds (VOCs) in the headspace of alfalfa infusions, eliciting attraction, were identified. While phenolic and indolic compounds were the most abundant bioactive VOCs, additional VOCs, including a monoterpene, were required to elicit a significant behavioural response to the synthetic odour blend of alfalfa infusions. Comparative analysis with the commercially available mosquito oviposition pheromone (MOP) was also conducted demonstrating that this standardised synthetic alfalfa infusion odour blend offers a promising lure for targeted surveillance and control of Culex mosquitoes, which may contribute to disease prevention and public health protection.

Distinct neurodevelopmental and epileptic phenotypes associated with gain- and loss-of-function GABRB2 variants

Variants in GABRB2, encoding the β2 subunit of the γ-aminobutyric acid type A (GABAA) receptor, can result in a diverse range of conditions, ranging from febrile seizures to severe developmental and epileptic encephalopathies. However, the mechanisms underlying the risk of developing milder vs more severe forms of disorder remain unclear. In this study, we conducted a comprehensive genotype-phenotype correlation analysis in a cohort of individuals with GABRB2 variants. Genetic and electroclinical data of 42 individuals harbouring 26 different GABRB2 variants were collected and accompanied by electrophysiological analysis of the effects of the variants on receptor function. Electrophysiological assessments of α1β2γ2 receptors revealed that 25/26 variants caused dysfunction to core receptor properties such as GABA sensitivity. Of these, 17 resulted in gain-of-function (GOF) while eight yielded loss-of-function traits (LOF). Genotype-phenotype correlation analysis revealed that individuals harbouring GOF variants suffered from severe developmental delay/intellectual disability (DD/ID, 74%), movement disorders such as dystonia or dyskinesia (59%), microcephaly (50%) and high risk of early mortality (26%). Conversely, LOF variants were associated with milder disease manifestations. Individuals with these variants typically exhibited fever-triggered seizures (92%), milder degrees of DD/ID (85%), and maintained ambulatory function (85%). Notably, severe movement disorders or microcephaly were not reported in individuals with loss-of-function variants. The data reveals that genetic variants in GABRB2 can lead to both gain and loss-of-function, and this divergence is correlated with distinct disease manifestations. Utilising this information, we constructed a diagnostic flowchart that aids in predicting the pathogenicity of recently identified variants by considering clinical phenotypes. This work was funded by the Australian National Health & Medical Research Council, the Novo Nordisk Foundation and The Lundbeck Foundation.

Electrophysiological Analysis of Retinal Organoid Development Using 3D Microelectrodes of Liquid Metals.

Despite of the substantial potential of human-derived retinal organoids, the degeneration of retinal ganglion cells (RGCs) during maturation limits their utility in assessing the functionality of later-born retinal cell subtypes. Additionally, conventional analyses primarily rely on fluorescent emissions, which limits the detection of actual cell functionality while risking damage to the 3D cytoarchitecture of organoids. Here, an electrophysiological analysis is presented to monitor RGC development in early to mid-stage retinal organoids, and compare distinct features with fully-mature mouse retina. This approach utilizes high-resolution 3D printing of liquid-metal microelectrodes, enabling precise targeting of specific inner retinal layers within organoids. The adaptable distribution and softness of these microelectrodes facilitate the spatiotemporal recording of inner retinal signals. This study not only demonstrates the functional properties of RGCs in retinal organoid development but also provides insights into their synaptic connectivity, reminiscent of fetal native retinas. Further comparison with fully-mature mouse retina in vivo verifies the organoid features, highlighting the potential of early-stage retinal organoids in biomedical research.

Portable multi-focal visual evoked potential diagnostics for multiple sclerosis/optic neuritis patients

PurposeMultiple sclerosis (MS) is a neuro-inflammatory disease affecting the central nervous system (CNS), where the immune system targets and damages the protective myelin sheath surrounding nerve fibers, inhibiting axonal signal transmission. Demyelinating optic neuritis (ON), a common MS symptom, involves optic nerve damage. We’ve developed NeuroVEP, a portable, wireless diagnostic system that delivers visual stimuli through a smartphone in a headset and measures evoked potentials at the visual cortex from the scalp using custom electroencephalography electrodes.MethodsSubject vision is evaluated using a short 2.5-min full-field visual evoked potentials (ffVEP) test, followed by a 12.5-min multifocal VEP (mfVEP) test. The ffVEP evaluates the integrity of the visual pathway by analyzing the P100 component from each eye, while the mfVEP evaluates 36 individual regions of the visual field for abnormalities. Extensive signal processing, feature extraction methods, and machine learning algorithms were explored for analyzing the mfVEPs. Key metrics from patients’ ffVEP results were statistically evaluated against data collected from a group of subjects with normal vision. Custom visual stimuli with simulated defects were used to validate the mfVEP results which yielded 91% accuracy of classification.Results20 subjects, 10 controls and 10 with MS and/or ON were tested with the NeuroVEP device and a standard-of-care (SOC) VEP testing device which delivers only ffVEP stimuli. In 91% of the cases, the ffVEP results agreed between NeuroVEP and SOC device. Where available, the NeuroVEP mfVEP results were in good agreement with Humphrey Automated Perimetry visual field analysis. The lesion locations deduced from the mfVEP data were consistent with Magnetic Resonance Imaging and Optical Coherence Tomography findings.ConclusionThis pilot study indicates that NeuroVEP has the potential to be a reliable, portable, and objective diagnostic device for electrophysiology and visual field analysis for neuro-visual disorders.

Exploring oak processionary caterpillar induced lepidopterism (part 2): ex vivo bio-assays unmask the role of TRPV1

As human skin comes into contact with the tiny hairs or setae of the oak processionary caterpillar, Thaumetopoea processionea, a silent yet intense chemical confrontation occurs. The result is a mix of issues: skin rashes and an intense itching that typically lasts days and weeks after the contact. This discomfort poses a significant health threat not only to humans but also to animals. In Western Europe, the alarming increase in outbreaks extends beyond areas near infested trees due to the dispersion of the setae. Predictions indicate a sustained rise in outbreaks, fueled by global changes favoring the caterpillar’s survival and distribution. Currently, the absence of an efficient treatment persists due to significant gaps in our comprehension of the pathophysiology associated with this envenomation. Here, we explored the interaction between the venom extract derived from the setae of T. processionea and voltage- and ligand-gated ion channels and receptors. By conducting electrophysiological analyses, we discovered ex vivo evidence highlighting the significant role of TPTX1-Tp1, a peptide toxin from T. processionea, in modulating TRPV1. TPTX1-Tp1 is a secapin-like peptide and demonstrates a unique ability to modulate TRPV1 channels in the presence of capsaicin, leading to cell depolarization, itch and inflammatory responses. This discovery opens new avenues for developing a topical medication, suggesting the incorporation of a TRPV1 blocker as a potential solution for the local effects caused by T. processionea.

Characterization of remodeling processes in the atria of atrioventricular block dogs: Utility as an early-stage atrial fibrillation model

To characterize utility of atrioventricular block (AVB) dogs as atrial fibrillation (AF) model, we studied remodeling processes occurring in their atria in acute (<2 weeks) and chronic (>4 weeks) phases. Fifty beagle dogs were used. Holter electrocardiogram demonstrated that paroxysmal AF occurred immediately after the production of AVB, of which duration tended to be prolonged in chronic phase. Electrophysiological analysis showed that inter-atrial conduction time and duration of burst pacing-induced AF increased in the chronic phase compared with those in the acute phase, but that atrial effective refractory period was hardly altered. Echocardiographic study revealed that diameters of left atrium, right pulmonary vein and inferior vena cava increased similarly in the acute and chronic phases. Histological evaluation indicated that hypertrophy and fibrosis in atrial tissue increased in the chronic phase. Electropharmacological characterization showed that i.v. pilsicainide effectively suppressed burst pacing-induced AF with increasing atrial conduction time and refractoriness of AVB dogs in chronic phase, but that i.v. amiodarone did not exert such electrophysiological effects. Taken together, AVB dogs in chronic phase appear to possess such pathophysiology as developed in the atria of early-stage AF patients, and therefore they can be used to evaluate drug candidates against early-stage AF.

Single-neuron projectome-guided analysis reveals the neural circuit mechanism underlying endogenous opioid antinociception.

Endogenous opioid antinociception is a self-regulatory mechanism that reduces chronic pain, but its underlying circuit mechanism remains largely unknown. Here, we showed that endogenous opioid antinociception required the activation of mu-opioid receptors (MORs) in GABAergic neurons of the central amygdala nucleus (CEA) in a persistent-hyperalgesia mouse model. Pharmacogenetic suppression of these CEAMOR neurons, which mimics the effect of MOR activation, alleviated the persistent hyperalgesia. Furthermore, single-neuron projection analysis revealed multiple projectome-based subtypes of CEAMOR neurons, each innervating distinct target brain regions. We found that the suppression of axon branches projecting to the parabrachial nucleus (PB) of one subtype of CEAMOR neurons alleviated persistent hyperalgesia, indicating a subtype- and axonal-branch-specific mechanism of action. Further electrophysiological analysis revealed that suppression of a distinct CEA-PB disinhibitory circuit controlled endogenous opioid antinociception. Thus, this study identified the central neural circuit that underlies endogenous opioid antinociception, providing new insight into the endogenous pain modulatory mechanisms.

Unveiling Tst3, a Multi-Target Gating Modifier Scorpion α Toxin from Tityus stigmurus Venom of Northeast Brazil: Evaluation and Comparison with Well-Studied Ts3 Toxin of Tityus serrulatus.

Studies on the interaction sites of peptide toxins and ion channels typically involve site-directed mutations in toxins. However, natural mutant toxins exist among them, offering insights into how the evolutionary process has conserved crucial sequences for activities and molecular target selection. In this study, we present a comparative investigation using electrophysiological approaches and computational analysis between two alpha toxins from evolutionarily close scorpion species of the genus Tityus, namely, Tst3 and Ts3 from T. stigmurus and T. serrulatus, respectively. These toxins exhibit three natural substitutions near the C-terminal region, which is directly involved in the interaction between alpha toxins and Nav channels. Additionally, we characterized the activity of the Tst3 toxin on Nav1.1-Nav1.7 channels. The three natural changes between the toxins did not alter sensitivity to Nav1.4, maintaining similar intensities regarding their ability to alter opening probabilities, delay fast inactivation, and induce persistent currents. Computational analysis demonstrated a preference for the down conformation of VSD4 and a shift in the conformational equilibrium towards this state. This illustrates that the sequence of these toxins retained the necessary information, even with alterations in the interaction site region. Through electrophysiological and computational analyses, screening of the Tst3 toxin on sodium isoform revealed its classification as a classic α-NaTx with a broad spectrum of activity. It effectively delays fast inactivation across all tested isoforms. Structural analysis of molecular energetics at the interface of the VSD4-Tst3 complex further confirmed this effect.

Sleep in the East African root rat, Tachyoryctes splendens.

The present study reports the results of an electrophysiological analysis of sleep in the East African root rat, Tachyoryctes splendens, belonging to the rodent subfamily Spalacinae. Telemetric electroencephalographic (EEG) and electromyographic recordings, with associated video recording, on three root rats over a continuous 72 h period (12 h light/12 h dark cycle) were analyzed. The analysis revealed that the East African root rat has a total sleep time (TST) of 8.9 h per day. Despite this relatively short total sleep time in comparison to fossorial rodents, nonrapid eye movement (non-REM) sleep and rapid eye movement (REM) sleep states showed similar physiological signatures to that observed in other rodents and no unusual sleep states were observed. REM occupied 19.7% of TST, which is within the range observed in other rodents. The root rats were extremely active during the dark period, and appeared to spend much of the light period in quiet wake while maintaining vigilance (as determined from both EEG recordings and behavioral observation). These recordings were made under normocapnic environmental conditions, which contrasts with the hypercapnic environment of their natural burrows.

Accelerating cell division of Shewanella oneidensis to promote extracellular electron transfer rate for efficient pollution treatment

The slow rate of extracellular electron transfer (EET) of electroactive microorganisms (EAMs) remains a predominate bottleneck that restricts practical applications of bio-electrochemical systems. Cell division has significant effects on cell cycle, morphology, growth and metabolism. However, the relation between cell division and the EET rate of Shewanella oneidensis has not been established. Here, we employed modular engineering strategy to accelerate DNA replication in the C period and divisome formation in the D period of cell cycle, which decreased cellular volume and enhanced the EET efficiency. Assembly of the C and D period modules further decreased the cell volume by 82.0 % and enhanced power density by 3.12-fold. Electrophysiological and transcriptomic analyses synergistically revealed that the programmed cell volume decrease facilitated lactate uptake and cellular metabolism due to the increased specific surface area (SSA), which consequently reinforced intracellular electron generation. Moreover, the reduced cell size facilitated electroactive biofilm formation. Finally, programmed increase in riboflavin biosynthesis and transport further strengthened indirect EET and boosted output power density to 1537.8 ± 116.9 mW m−2, 21.1-fold of that of the WT. The engineered strains exhibited superior abilities for Cr6+ reduction and azo dyes degradation. This study shed light on the underlying mechanism how reduced cell size impacts electrophysiology of EAMs, and indicated accelerating cell division is a promising avenue to increase the EET of EAMs for efficient environmental pollution treatment.

New recellularizable cardio-matrix scaffold as a base for alternative in vitro models for the cardiotoxicity risk prediction

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): SID 227944/22 DOR 2331157/23 Background Cardiotoxicity is the occurrence of cardiac dysfunction induced by pathophysiological stimuli as a result of toxic effects. A considerable number of drugs, including chemotherapics, antibiotics antidepressants but also antiarrhythmics, could cause an alteration of cardiac physiology, and then cardiac damage. These include disturbances in ventricular repolarization and QT interval, arrhythmias, bradycardia, tachycardia, decreases in left ventricular ejection fraction, and congestive heart failure. Precinical evaluation of drug cardiotoxicity has used animal models, which tend to be expensive, have lo throughput, and have limitations as not ever faithfully reflect the human pathophysiology, while current two-dimensional cellular models revealed to be not sufficient and specific. Purpose The aim of this study is to develop a myocardial tissue-like scaffold, in order to realize an efficient and easy-replicable in vitro model for drug cardiotoxicity prediction. This must be able to mimic the morphological, cellular, and electrophysiological complexity of the intact adult human myocardium. Material and Methods Starting from fresh porcine hearts, cardiac specimens were isolated from left ventricles using a scalpel, sectioned with a vibratome and punched with a biopsy puncher obtaining myocardial patches. Thus, samples were decellularized through a novel serial decellularization treatment based on osmotic shock and detergents. The decellularization procedure exploited a new automated, dynamic perfusion device for a standardized and optimized removal of cardiac cells and non-ECM proteins. These samples were analysed for decellularization effectiveness by DNA quantification, histology and immunofluorescence staining to evaluate cell removal and extracellular matrix integrity. Moreover, they were tested for cytocompatibility using human mesenchymal stem cells and cardiac progenitors, also derived from induced pluripotent stem cells. Cellular adhesion, behaviour, vitality, proliferation, and possible apoptotic effects were tested, too. Results In order to advance a robust bioelectronics model, an automated platform was developed to generate a three-dimensional, bioengineered replica of human myocardial tissue. With respect to the common decellularization protocol characterized by mild agitation, results based on the automated, dynamic treatments have shown a superior ability to obtain acellular, biocompatible scaffolds in terms of cell elements’ removal and extracellular matrix preservation, as well as time- and cost-effectiveness. Indeed, these decellularized scaffolds allow cell penetration, adhesion and survival. Conclusions Further experiments will be focused on evaluating functional bioengineered myocardial tissues with electrophysiological and molecular analysis to evaluate this new model's throughput capacity. Finally, the validation of these bioelectronic platforms will be performed with drugs with known cardiotoxic effects.

Acquired control over proliferation and differentiation of ventricular cardiomyocytes to break down the mechanisms of cardiac repair

Abstract Funding Acknowledgements None. Loss of myocardial tissue remains a leading cause of morbidity and mortality by causing heart rhythm disturbances and heart failure. The (pre-)clinical effects of inducing cardiac regeneration by cardiac cell therapy have been disappointing. In order to find new curative options for these disabling cardiac diseases a shift of focus towards steering the heart to regenerate itself is needed. The aim of this study was to generate a robust ventricular cardiomyocyte model in which proliferation and differentiation could be tightly controlled to investigate cardiac regeneration. To accomplish this we have generated a line of immortalized neonatal rat ventricular cardiomyocytes (nrVMs) through expression of the cell cycle regulators cyclin-dependent kinase 4 and cyclin D1 (CDK4-D1). The CDK4-D1 expressing nrVMs were positive for the proliferation marker Ki67 in contrast to control nrVMs. Cardiomyogenic differentiation could still be induced after multiple passages (&amp;gt; passage 10) as evidenced by immunocytochemistry and optical voltage mapping. These contractile and excitable cells were indeed positive for the cardiac-specific sarcomeric proteins alpha actinin and troponin T in a sarcomeric pattern similar to native nrVMs. Passaging of the control nrVM cultures, however, ultimately led to a senescent cell population lacking sarcomeric markers after passage 3. Electrophysiological analysis of immortalized monolayers, after inducing cardiomyogenic differentiation, showed not only uniform propagation of electrical signal throughout the cultures, but also re-entrant activity although at low frequency. In conclusion, these data show that were able to immortalize ventricular cardiomyocytes by preserving their contractile and excitable phenotype upon significant expansion. Further optimisation of this model will lead to a research model of ventricular cardiomyocytes which will give us the opportunity to unravel the process of cardiomyogenesis and uncover mechanisms which could allow us to enhance the ability of the heart to regenerate itself.

Oral curcumin ameliorates acute murine campylobacteriosis

IntroductionHuman infections with the food-borne enteropathogen Campylobacter jejuni are responsible for increasing incidences of acute campylobacteriosis cases worldwide. Since antibiotic treatment is usually not indicated and the severity of the enteritis directly correlates with the risk of developing serious autoimmune disease later-on, novel antibiotics-independent intervention strategies with non-toxic compounds to ameliorate and even prevent campylobacteriosis are utmost wanted. Given its known pleiotropic health-promoting properties, curcumin constitutes such a promising candidate molecule. In our actual preclinical placebo-controlled intervention trial, we tested the anti-microbial and anti-inflammatory effects of oral curcumin pretreatment during acute experimental campylobacteriosis.MethodsTherefore, secondary abiotic IL-10-/- mice were challenged with synthetic curcumin via the drinking water starting a week prior oral C. jejuni infection. To assess anti-pathogenic, clinical, immune-modulatory, and functional effects of curcumin prophylaxis, gastrointestinal C. jejuni bacteria were cultured, clinical signs and colonic histopathological changes quantitated, pro-inflammatory immune cell responses determined by in situ immunohistochemistry and intestinal, extra-intestinal and systemic pro-inflammatory mediator measurements, and finally, intestinal epithelial barrier function tested by electrophysiological resistance analysis of colonic ex vivo biopsies in the Ussing chamber.Results and discussionWhereas placebo counterparts were suffering from severe enterocolitis characterized by wasting symptoms and bloody diarrhea on day 6 post-infection, curcumin pretreated mice, however, were clinically far less compromised and displayed less severe microscopic inflammatory sequelae such as histopathological changes and epithelial cell apoptosis in the colon. In addition, curcumin pretreatment could mitigate pro-inflammatory innate and adaptive immune responses in the intestinal tract and importantly, rescue colonic epithelial barrier integrity upon C. jejuni infection. Remarkably, the disease-mitigating effects of exogenous curcumin was also observed in organs beyond the infected intestines and strikingly, even systemically given basal hepatic, renal, and serum concentrations of pro-inflammatory mediators measured in curcumin pretreated mice on day 6 post-infection. In conclusion, the anti-Campylobacter and disease-mitigating including anti-inflammatory effects upon oral curcumin application observed here highlight the polyphenolic compound as a promising antibiotics-independent option for the prevention from severe acute campylobacteriosis and its potential post-infectious complications.

Molecular and functional profiling of cell diversity and identity in the lateral superior olive, an auditory brainstem center with ascending and descending projections

The lateral superior olive (LSO), a prominent integration center in the auditory brainstem, contains a remarkably heterogeneous population of neurons. Ascending neurons, predominantly principal neurons (pLSOs), process interaural level differences for sound localization. Descending neurons (lateral olivocochlear neurons, LOCs) provide feedback into the cochlea and are thought to protect against acoustic overload. The molecular determinants of the neuronal diversity in the LSO are largely unknown. Here, we used patch-seq analysis in mice at postnatal days P10-12 to classify developing LSO neurons according to their functional and molecular profiles. Across the entire sample (n = 86 neurons), genes involved in ATP synthesis were particularly highly expressed, confirming the energy expenditure of auditory neurons. Two clusters were identified, pLSOs and LOCs. They were distinguished by 353 differentially expressed genes (DEGs), most of which were novel for the LSO. Electrophysiological analysis confirmed the transcriptomic clustering. We focused on genes affecting neuronal input–output properties and validated some of them by immunohistochemistry, electrophysiology, and pharmacology. These genes encode proteins such as osteopontin, Kv11.3, and Kvβ3 (pLSO-specific), calcitonin-gene-related peptide (LOC-specific), or Kv7.2 and Kv7.3 (no DEGs). We identified 12 “Super DEGs” and 12 genes showing “Cluster similarity.” Collectively, we provide fundamental and comprehensive insights into the molecular composition of individual ascending and descending neurons in the juvenile auditory brainstem and how this may relate to their specific functions, including developmental aspects.

Activation of GPR55 Ameliorates Maternal Separation-Induced Learning and Memory Deficits by Augmenting 5-HT Synthesis in the Dorsal Raphe Nucleus of Juvenile Mice.

Maternal separation (MS) represents a profound early life stressor with enduring impacts on neuronal development and adult cognitive function in both humans and rodents. MS is associated with persistent dysregulations in neurotransmitter systems, including the serotonin (5-HT) pathway, which is pivotal for mood stabilization and stress-coping mechanisms. Although the novel cannabinoid receptor, GPR55, is recognized for its influence on learning and memory, its implications on the function and synaptic dynamics of 5-HT neurons within the dorsal raphe nucleus (DRN) remain to be elucidated. In this study, we sought to discern the repercussions of GPR55 activation on 5-HT synthesis within the DRN of adult C57BL/6J mice that experienced MS. Concurrently, we analyzed potential alterations in excitatory synaptic transmission, long-term synaptic plasticity, and relevant learning and memory outcomes. Our behavioral assessments indicated a marked amelioration in MS-induced learning and memory deficits following GPR55 activation. In conjunction with this, we noted a substantial decrease in 5-HT levels in the MS model, while GPR55 activation stimulated tryptophan hydroxylase 2 synthesis and fostered the release of 5-HT. Electrophysiological patch-clamp analyses highlighted the ability of GPR55 activation to alleviate MS-induced cognitive deficits by modulating the frequency and magnitude of miniature excitatory postsynaptic currents within the DRN. Notably, this cognitive enhancement was underpinned by the phosphorylation of both NMDA and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. In summary, our findings underscore the capacity of GPR55 to elevate 5-HT synthesis and modify synaptic transmissions within the DRN of juvenile mice, positing GPR55 as a promising therapeutic avenue for ameliorating MS-induced cognitive impairment.

Chemogenetic activation of mammalian brain neurons expressing insect Ionotropic Receptors by systemic ligand precursor administration

Chemogenetic approaches employing ligand-gated ion channels are advantageous regarding manipulation of target neuronal population functions independently of endogenous second messenger pathways. Among them, Ionotropic Receptor (IR)-mediated neuronal activation (IRNA) allows stimulation of mammalian neurons that heterologously express members of the insect chemosensory IR repertoire in response to their cognate ligands. In the original protocol, phenylacetic acid, a ligand of the IR84a/IR8a complex, was locally injected into a brain region due to its low permeability of the blood-brain barrier. To circumvent this invasive injection, we sought to develop a strategy of peripheral administration with a precursor of phenylacetic acid, phenylacetic acid methyl ester, which is efficiently transferred into the brain and converted to the mature ligand by endogenous esterase activities. This strategy was validated by electrophysiological, biochemical, brain-imaging, and behavioral analyses, demonstrating high utility of systemic IRNA technology in the remote activation of target neurons in the brain.

A pig model of symptomatic spinal epidural hematoma.

The purpose of this study was to establish an animal model capable of simulating the development and decompression process of symptomatic spinal epidural hematoma (SSEH). A total of 16 male Bama miniature pigs were included in this study and randomly allocated into four groups: Group A (4h 20mmHg hematoma compression), Group B (4h 24mmHg hematoma compression), Group C (4h 28mmHg hematoma compression), and Group Sham (control). Real-time intra-wound hematoma compression values were obtained using the principle of connectors. Electrophysiological analyses, including the latency and amplitude of somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP), along with behavioral observations (Tarlov score), were performed to assess this model. ANOVA tests demonstrated significant differences in the latency and relative amplitude of SSEP and MEP between Groups C and Sham after 4h of hematoma compression and one month after surgery (P < 0.01). Behavioral assessments 8h after surgery indicated that animals subjected to 28mmHg hematoma compression suffered the most severe spinal cord injury. Pearson correlation coefficient test suggested a negative correlation between the epidural pressure and Tarlov score (r = -0.700, p < 0.001). With the progression of compression and the escalation of epidural pressure, the latency of SSEP and MEP gradually increased, while the relative amplitude gradually decreased. When the epidural pressure reaches approximately 24mmHg, the spinal cord function occurs progressive dysfunction. Monitoring epidural pressure would be an effective approach to assist to identify the occurrence of postoperative SSEH.