Delta opioid receptors (DORs) are widely expressed throughout the central nervous system, including the cerebellum, where they play a regulatory role in neurogenesis. In the cerebellar cortex, Purkinje cells (PCs), the sole output neurons, receive glutamatergic synaptic input from parallel fibers (PFs)—the axonal extensions of granule cells—forming PF-PC synapses. However, the precise distribution of DORs within these synapses and their impact on synaptic transmission remain unclear. In this study, we utilized whole-cell patch-clamp recordings and neuropharmacological approaches to explore the effects of DORs activation on PF-PC synaptic transmission in the mouse cerebellar cortex and to elucidate the underlying mechanisms. We found that the selective DORs agonist DPDPE significantly reduced the amplitude and area under the curve (AUC) of PF-PC evoked excitatory postsynaptic currents (eEPSCs), accompanied by an increase in the paired-pulse ratio (PPR). This inhibitory effect was blocked by the DORs antagonist Naltrindole. Additionally, DPDPE decreased the frequency of PF-PC miniature excitatory postsynaptic currents (mEPSCs) without affecting their amplitude, indicating a presynaptic site of action. When the protein kinase A (PKA) inhibitor PKI was added to the internal solution of the recording electrode, it did not alter the DPDPE-induced suppression of PF-PC mEPSC frequency. However, this suppression was reversed by KT5720, a cell-permeable PKA-specific inhibitor. These findings suggest that DPDPE inhibits PF-PC synaptic transmission through the preferential activation of presynaptic DORs, with this process being dependent on the cyclic adenosine monophosphate (cAMP)-PKA signaling pathway.

Depression and anxiety are prominent symptoms of withdrawal syndrome, often caused by the abuse of addictive drugs like morphine. N-palmitoylethanolamide (PEA), a biologically active lipid, is utilized as an anti-inflammatory and analgesic medication. Recent studies have highlighted PEA's role in mitigating cognitive decline and easing depression resulting from chronic pain. However, it remains unknown whether PEA can influence negative emotions triggered by morphine withdrawal. This study seeks to explore the impact of PEA on such emotions and investigate the underlying mechanisms. Mice subjected to morphine treatment underwent a 10-day withdrawal period, followed by assessments of the effect of PEA on anxiety- and depression-like behaviors using various tests. Enzyme-linked immunosorbent assay was conducted to measure levels of monoamine neurotransmitters in specific brain regions. The findings indicate that PEA mitigated anxiety and depression symptoms and reduced 5-hydroxytryptamine, noradrenaline, and dopamine levels in the hippocampus and prefrontal cortex. In summary, PEA demonstrates a significant positive effect on negative emotions associated with morphine withdrawal, accompanied with the reduction in levels of monoamine neurotransmitters in key brain regions. These insights could be valuable for managing negative emotions arising from morphine withdrawal.

Rapid progress in nanotechnology has advanced fundamental neuroscience and innovative treatment using combined diagnostic and therapeutic applications. The atomic scale tunability of nanomaterials, which can interact with biological systems, has attracted interest in emerging multidisciplinary fields. Graphene, a two-dimensional nanocarbon, has gained increasing attention in neuroscience due to its unique honeycomb structure and functional properties. Hydrophobic planar sheets of graphene can be effectively loaded with aromatic molecules to produce a defect-free and stable dispersion. The optical and thermal properties of graphene make it suitable for biosensing and bioimaging applications. In addition, graphene and its derivatives functionalized with tailored bioactive molecules can cross the blood–brain barrier for drug delivery, substantially improving their biological property. Therefore, graphene-based materials have promising potential for possible application in neuroscience. Herein, we aimed to summarize the important properties of graphene materials required for their application in neuroscience, the interaction between graphene-based materials and various cells in the central and peripheral nervous systems, and their potential clinical applications in recording electrodes, drug delivery, treatment, and as nerve scaffolds for neurological diseases. Finally, we offer insights into the prospects and limitations to aid graphene development in neuroscience research and nanotherapeutics that can be used clinically.

Drug abuse remains a global problem; nonetheless, its mechanism has not yet been fully understood. Recent studies have reported on the non-motor functions of the cerebellum, and evidence from neuroimaging and behavioral studies has suggested the role of cerebellum in drug reward, which has received increasing attention. Furthermore, emerging technological developments have aided in clarifying the various circuits and functions of the cerebellum. Exploring the role of the cerebellum in drug reward can improve our understanding of the mechanism underlying addiction and facilitate the development of new treatment schemes. This review summarizes the anatomy of the cerebellum and its connections to brain regions considered important in addiction. Subsequently, we investigate the neurological reasons elucidating why the cerebellum is a potential target for drug reward. Additionally, we expound the molecular targets of addictive drugs in the cerebellum, mainly glutamate and endocannabinoids. Unlike previous studies, this article focuses on the influence of alcohol, nicotine, morphine, cannabis, and cocaine on the cerebellum from multiple viewpoints, including imaging and behavioral changes, molecular signals, neurotransmitters, and synaptic transmission. We aim to clarify some drug-induced cerebellar changes to supplement the previous research regarding the relationship between addiction and the cerebellum. Finally, we discuss the limitations and prospects of drug reward research on the cerebellum to provide novel insights into studying the cerebellum and its role in addiction. We recommend that future addiction network models should include the cerebellum to provide new therapeutic targets for treating addiction.

Neurotransmitters are biologically active molecules that are crucial for the regulation of normal physi-ological functions in the central and peripheral nervous systems. Therefore, accurate detection of neu-rotransmitters is significant in many applications, such as clinical diagnosis, biological analysis, and pathological research. However, quantitative analysis of neurotransmitters is difficult as they are released dynamically and at very low concentrations (e.g., dopamine is released at concentrations of 0.065-0.326 nM) [64]. In this regard, microelectrodes have attracted considerable attention as electrochemical biosensors owing to their excellent sensitivity, high response rate, and high stability. Among the various electrode materials, carbon has shown high potential owing to its high electrical conductivity and low cost. Moreover, carbon-based microelectrodes can be used in real time in vivo to detect neurotrans-mitters. This review summarizes the various carbon-based microelectrodes developed as biosensors and discusses their sensitivity and limit of detection with regard to neurotransmitters. The review provides insight into the development of carbon-based microelectrodes as biosensors to detect neurotransmitters and the future prospects and commercialization capabilities of such devices.(c) 2022 Elsevier B.V. All rights reserved.

Opioid receptors play important roles in, among others, learning and memory, emotional responses, addiction, and pain. In recent years, the cerebellum has received increasing attention for its role in non-motor functions. The Purkinje cell (PC) is the only efferent neuron in the cerebellar cortex, and receives glutamatergic synaptic inputs from the parallel fibers (PF) formed by the axons of granule cells. Studies have shown that opioid receptors are expressed during the development of cerebellar cells. However, the distribution of opioid receptors, their subtypes in cerebellar PF-PC synapses, and their effects on synaptic transmission remain unclear. To examine these questions, we used whole-cell patch clamp recordings and pharmacological methods to determine the effects of activating three different opioid receptor subtypes on synaptic transmission at PF-PC synapses. In the presence of picrotoxin, mouse cerebellar slices were perfused with agonists or blockers of different opioid receptor subtypes, and the changes in excitatory postsynaptic currents (EPSCs) were examined. Both agonists of µ-opioid receptors (MOR) and δ-opioid receptors (DOR) significantly reduced the amplitude and area under the curve of PF-PC EPSCs in a concentration-dependent manner, accompanied by an increase in the paired-pulsed ratio (PPR). These effects could be blocked by respective receptor antagonists. In contrast, no significant changes were found after the application of κ-opioid receptor (KOR) agonists. In conclusion, MOR and DOR are present at the axon terminals of PF in the mouse cerebellar cortex, whereas no or negligible amounts of KOR are found. Activation of MOR and DOR regulates PF-PC synaptic transmission via inhibition of glutamate (Glu) release in cerebellar cortex in mice. We also found that endogenous opioid peptides are present in PF-PC synapses of mouse cerebellum, which also can inhibit the release of Glu.

μ-opioid receptors (MOR) are widely expressed in the brain, varying in density in different areas. Activation of MORs underlies analgesia, euphoria, but may lead to tolerance, dependence, and ultimately opioid addiction. The Purkinje cell (PC) is the only efferent neuron in the cerebellar cortex and receives glutamatergic synaptic inputs from the parallel fibers formed by the axons of granule cells. Studies have shown that MORs are expressed during the development of cerebellar cells. However, the distribution of MOR and their effects on PF-PC synaptic transmission remain unclear. To examine these questions, we used whole-cell patch clamp recordings and pharmacological methods to determine the effects and mechanisms of MOR activation on synaptic transmission at PF-PC synapses. The MOR-selective agonist DAMGO significantly reduced the amplitude and area under the curve (AUC) of PF-PC evoked (e) EPSCs, and increased the paired-pulse ratio (PPR).DAMGO-induced inhibitory effects on PF-PC eEPSCs and PPR were abolished by MOR specific blocker CTOP. Further, DAMGO significantly reduced the frequency of PF-PC mEPSCs, but had no obvious effect on their amplitude, suggesting a presynaptic site of action. The DAMGO-induced reduction in the frequency of PF-PC mEPSCs also was blocked by CTOP. A protein kinase A (PKA) inhibitor PKI added in the pipette solution did not affect the inhibitory effects on PF-PC mEPSCs induced by DAMGO. Both the PKA inhibitor K5720 and MEK inhibitor U0126 in artificial cerebrospinal fluid (ACSF) prevented the inhibitory effects of DAMGO on PF-PC mEPSCs. These findings reveal that MORs are expressed in presynaptic PF axon terminals, where DAMGO can activate presynaptic MORs to inhibit PF-PC synaptic transmission by regulating the release of glutamate. G-protein-dependent cAMP-PKA signaling pathway may be involved in this process.

Fentanyl as a synthetic opioid works by binding to the mu-opioid receptor (MOR) in brain areas to generate analgesia, sedation and reward related behaviors. As we know, cerebellum is not only involved in sensory perception, motor coordination, motor learning and precise control of autonomous movement, but also important for the mood regulation, cognition, learning and memory. Previous studies have shown that functional MORs are widely distributed in the cerebellum, and the role of MOR activation in cerebellum has not been reported. The aim of the present study was to investigate the effects of fentanyl on air-puff stimulus-evoked field potential response in the cerebellar molecular layer using in vivo electrophysiology in mice. The results showed that perfusion of 5 μmol/L fentanyl on the cerebellar surface significantly inhibited the amplitude, half width and area under the curve (AUC) of sensory stimulation-evoked inhibitory response P1 in the molecular layer. The half-inhibitory concentration (IC50) of the fentanyl-induced suppression of P1 amplitude was 4.21 μmol/L. The selective MOR antagonist CTOP abolished fentanyl-induced inhibitory responses in the molecular layer. However, application of CTOP alone increased the amplitude and AUC of P1. Notably, fentanyl significantly inhibited the tactile stimulation-evoked response of molecular layer interneurons (MLIs) and the spontaneous firing of MLIs. The results suggest that fentanyl attenuates air-puff stimulus-evoked field potential response in the cerebellar molecular layer via binding to MOR to restrain the spontaneous and evoked firing of MLIs.

[目的]探讨延胡索乙素(l-THP)对福尔马林致痛大鼠的镇痛作用及其机制.[方法]取清洁级雄性SD大鼠,随机分为生理盐水对照组、福尔马林模型组、布洛芬阳性对照组及l-THP高、中、低剂量组.观察l-THP对福尔马林致痛大鼠舔爪时间、L4-L5脊髓后角c-Fos蛋白及5-HT2A受体表达的影响.[结果]大鼠足底注射给予福尔马林后出现双相痛的表现.与福尔马林模型组比较,布洛芬阳性对照组及l-THP高、中、低剂量组福尔马林诱导的第Ⅱ相痛时间均明显缩短(P＜0.05).大鼠足底注射给予福尔马林30、60、90 min时L4-L5腰段脊髓灰质后角均有c-Fos蛋白和5-HT2A受体表达,且均在60 min时表达最明显.大鼠足底注射给予福尔马林60 min后,福尔马林模型组大鼠L4-L5腰段脊髓灰质后角内c-Fos表达水平明显高于生理盐水对照组(P＜0.05),布洛芬阳性对照组及l-THP高、中、低剂量组c-Fos表达水平均明显低于福尔马林模型组(P＜0.05);福尔马林模型组大鼠L4-L5腰段脊髓灰质后角内5-HT2A受体表达水平较生理盐水对照组明显升高(P＜0.05),布洛芬阳性对照组及l-THP高、中、低剂量组5-HT2A受体表达水平均明显低于福尔马林模型组(P＜0.05).[结论]L4-L5脊髓后角c-Fos蛋白和5-HT2A受体参与了由福尔马林诱导的机体疼痛感觉过程;l-THP对福尔马林引起的疼痛效应具有抑制作用,且中、高剂量l-THP的抑制作用较布洛芬的效果更为显著,其作用机制可能是由5-HT2A受体所介导的.

The comorbidity of depression and addiction has become a serious public health issue, and the relationship between these two disorders and their potential mechanisms has attracted extensive attention. Numerous studies have suggested that depression and addiction share common mechanisms and anatomical pathways. The nucleus accumbens (NAc) has long been considered a key brain region for regulating many behaviors, especially those related to depression and addiction. In this review article, we focus on the association between addiction and depression, highlighting the potential mediating role of the NAc in this comorbidityviathe regulation of changes in the neural circuits and molecular signaling. To clarify the mechanisms underlying this association, we summarize evidence from overlapping reward neurocircuitry, the resemblance of cellular and molecular mechanisms, and common treatments. Understanding the interplay between these disorders should help guide clinical comorbidity prevention and the search for a new target for comorbidity treatment.

Aim: To examine the effects of fentanyl, a potent mu-opioid receptor (MOR) agonist, on-air puff-evoked responses in Purkinje cells (PCs), and molecular layer interneurons (MLIs) using in vivo patch-clamp recordings in anesthetized mice. Methods: Male mice 6-8 weeks-old were anesthetized and fixed on a custom-made stereotaxic frame. The cerebellar surface was exposed and perfused with oxygenated artificial cerebrospinal fluid (ACSF). Patch-clamp recordings in the cell-attached mode were obtained from PCs and MLIs. Facial stimulation by air-puff of the ipsilateral whisker pad was performed through a pressurized injection system. Fentanyl citrate, CTOP, and H-89 dissolved in ACSF were perfused onto the cerebellar surface. Results: Fentanyl significantly inhibited the amplitude and area under the curve (AUC) of sensory stimulation-evoked inhibitory responses in PCs. Although fentanyl did not influence the frequency of simple spikes (SSs), it decreased the pause of SS. The IC50 of the fentanyl-induced suppression of the P1 response amplitude was 5.53 μM. The selective MOR antagonist CTOP abolished fentanyl-induced inhibitory responses in PCs. However, the application of CTOP alone increased the amplitude, AUC of P1, and the pause of SS. Notably, fentanyl significantly inhibited the tactile-evoked response of MLIs but did not affect their spontaneous firing. The fentanyl-induced decrease of inhibitory responses in PCs was partially prevented by a PKA inhibitor, H-89. Conclusions: These results suggest that fentanyl binds to MORs in MLIs to reduce GABAergic neurotransmission in MLI-PC projections and one potential mechanism is via modulation of the cAMP-PKA pathway.

[目的]观察人参皂苷Re对吗啡依赖戒断后小鼠抑郁样行为的影响.[方法]取40只昆明种 雄性小鼠,分为生理盐水组和吗啡组,按照递增给药方式制作吗啡依赖模型,从两组中各取10只给予纳洛酮催瘾,观察戒断症状;其余小鼠自然放置,分别在戒断第1,10,14天时观察旷场、高架十字迷宫和强迫游泳实验中的行为学指标.另取40只小鼠随机分为对照组、人参皂苷Re小、中、大剂量(5,10,20mg/kg)组.制作吗啡依赖模型成功后,自第8天起连续14d灌胃给予人参皂苷Re小、中、大剂量组小鼠相应剂量的人参皂苷Re,对照组连续灌胃给予二蒸水,观察各组小鼠旷场、高架十字迷宫和强迫游泳实验中的行为学指标.[结果]连续7d皮下注射给予吗啡后小鼠体质量未出现明显增加(P＞0.05),给予纳洛酮催瘾后小鼠出现急性戒断症状;自然戒断第14天时小鼠抑郁样行为最明显;连续灌胃给药14 d后人参皂苷Re中、大剂量组小鼠中心区域活动时间明显延长(P＜0.05),大剂量组小鼠角落停留时间明显缩短(P＜0.05),人参皂苷Re中、大剂量组小鼠开臂停留时间百分率和强迫游泳时间均明显延长(P＜0.05).[结论]人参皂苷Re对吗啡依赖戒断后小鼠抑郁样行为具有改善作用.

Objective To observe the level changes of glutamate(Glu) and aspartic acid (ASP) in the Rostral Ventrolateral Medulla(RVLM) in sodium nitroprusside (SNP)-induced acute hypotension.Methods Forty adult male Wistar rats were divided into four groups:sham-operated group(Sham),bilateral labyrinthectomy group(BL),sinoaortic denervation group(SAD) and SAD+BL group.To investigate the level changes of Glu and ASP in RVLM in Sham,BL,SAD,SAD+BL groups following SNP infusion.Results (1)Infusion SNP decreased the mean blood pressure in Sham,BL,SAD and BL+SAD groups,and the blood pressure return to the baseline when infusion finished.(2) There was no significant difference in the level of Glu and ASP release in the RVLM in 4 groups before SNP infusion.(3) The level of Glu and ASP release peaked 10 min after SNP infusion in all 4 groups,and the level of Glu and ASP in BL,SAD and BL+ SAD groups were obviously decreased compared with Sham group.

学科竞赛、大创计划是培养创新型人才的重要平台和途径,文章以学科竞赛、大创计划为导向,从目标体系、内容体系、管理体系、保障体系等方面建立培养创新型人才为目标的基础医学实践教学体系,寻求大学生创新能力和实践能力培养的有效途径,对医学生的实践能力、创新能力、创业能力和团队精神有着重要的意义.

N-methyl-D-aspartate receptors (NMDARs) are post-synaptically expressed at climbing fiber-Purkinje cell (CF-PC) synapses in cerebellar cortex in adult mice and contributed to CF-PC synaptic transmission under in vitro conditions. In this study, we investigated the role of NMDARs at CF-PC synapses during the spontaneous complex spike (CS) activity in cerebellar cortex in urethane-anesthetized mice, by in vivo whole-cell recording technique and pharmacological methods. Under current-clamp conditions, cerebellar surface application of NMDA (50 μM) induced an increase in the CS-evoked pause of simple spike (SS) firing accompanied with a decrease in the SS firing rate. Under voltage-clamp conditions, application of NMDA enhanced the waveform of CS-evoked inward currents, which expressed increases in the area under curve (AUC) and spikelet number of spontaneous CS. NMDA increased the AUC of spontaneous CS in a concentration-dependent manner. The EC50 of NMDA for increasing AUC of spontaneous CS was 33.4 μM. Moreover, NMDA significantly increased the amplitude, half-width and decay time of CS-evoked after-hyperpolarization (AHP) currents. Blockade of NMDARs with D-(-)-2-amino-5-phosphonopentanoic acid (D-APV, 250 μM) decreased the AUC, spikelet number, and amplitude of AHP currents. In addition, the NMDA-induced enhancement of CS activity could not be observed after α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors were blocked. The results indicated that NMDARs of CF-PC synapses contributed to the spontaneous CS activity by enhancing CS-evoked inward currents and AHP currents.

Input signals originating from baroreceptors and vestibular receptors are integrated in the rostral ventrolateral medulla (RVLM) to maintain blood pressure during postural movement. The contribution of baroreceptors and vestibular receptors in the maintenance of blood pressure following hypotension were quantitatively analyzed by measuring phosphorylated extracellular regulated protein kinase (pERK) expression and glutamate release in the RVLM. The expression of pERK and glutamate release in the RVLM were measured in conscious rats that had undergone bilateral labyrinthectomy (BL) and/or sinoaortic denervation (SAD) following hypotension induced by a sodium nitroprusside (SNP) infusion. The expression of pERK was significantly increased in the RVLM in the control group following SNP infusion, and expression peaked 10 min after SNP infusion. The number of pERK positive neurons increased following SNP infusion in BL, SAD, and BL+SAD groups, although the increase was smaller than seen in the control group. The SAD group showed a relatively higher reduction in pERK expression when compared with the BL group. The level of glutamate release was significantly increased in the RVLM in control, BL, SAD groups following SNP infusion, and this peaked 10 min after SNP infusion. The SAD group showed a relatively higher reduction in glutamate release when compared with the BL group. These results suggest that the baroreceptors are more powerful in pERK expression and glutamate release in the RVLM following hypotension than the vestibular receptors, but the vestibular receptors still have an important role in the RVLM.

Propofol is a global central nervous system depressant that affects information processing in the central nervous system. However, the effects of propofol on sensory information processing in the cerebellar cortical molecular layer are unknown. In this study, we examined the effects of propofol on the dynamics of sensory stimulation-evoked responses in the cerebellar molecular layer in urethane-anesthetized mice, using electrophysiological and pharmacological methods. Our results showed that cerebellar surface perfusion of propofol (10-1,000 μmol/l) significantly decreased amplitude and area under the curve (AUC) of the sensory stimulation-evoked inhibitory component (P1) but increased the rise time and decay time of P1. In contrast, administration of propofol significantly enhanced the sensory stimulation-evoked excitatory component (N1), which exhibited increases in amplitude and AUC, as well as increases in rise time and decay time. By blocking the GABAA receptor activity, propofol failed to increase the amplitude and the AUC of the excitatory postsynaptic component (N2) of PCs. Our present results suggest that propofol modulates the dynamic properties of the sensory information processing in the cerebellar molecular layer through the modulation of GABAA receptors activity in the adult mouse.

Control of blood pressure is maintained by the interaction between the arterial baroreflex and vestibulosympathetic reflex during postural changes. In this study, the contributions of vestibular receptors and baroreceptors to the maintenance of blood pressure following acute hypotension were compared in terms of phosphorylated extracellular regulated protein kinase (pERK) expression in the nucleus tractus solitaries (NTS). Expression of pERK in the NTS was measured in conscious rats that had undergone bilateral labyrinthectomy (BL) and/or sinoaortic denervation (SAD) 5, 10, 20, and 40 min following acute hypotension induced by sodium nitroprusside (SNP) infusion. Expression of pERK increased significantly in the NTS in the control group following SNP infusion, and the expression peaked at 10 min after SNP infusion. The number of pERK positive neurons increased following SNP infusion in BL, SAD, and BL+SAD groups, although the increase was smaller than in control group. The BL group showed a relatively higher reduction in pERK expression than the SAD group, and the pERK expression in the NTS was localized to the caudal portion of the nuclei in the BL and SAD groups. These results suggest that the vestibular receptors may play a key role in maintaining blood pressure following acute hypotension; thus, the vestibular system may contribute to compensate for orthostatic hypotension.