Alzheimer's disease (AD), a prototypical neurodegenerative disorder, encompasses multifaceted pathological processes. As pivotal cellular structures within the central nervous system, ion channels play critical roles in regulating neuronal excitability, synaptic transmission, and neurotransmitter release. Extensive research has revealed significant alterations in the expression and function of ion channels in AD, implicating an important role of ion channels in the pathogenesis of abnormal Aβ deposition, neuroinflammation, oxidative stress, and disruptions in calcium homeostasis and neural network functionality. This review systematically summarizes the crucial roles and underlying mechanisms of ion channels in the onset and progression of AD, highlighting how these channel abnormalities contribute to AD pathophysiology. We also discuss the therapeutic potential of ion channel modulation in AD treatment, emphasizing the importance of addressing multifactorial nature and heterogeneity of AD. The development of multi-target drugs and precision therapies is proposed as a future direction of scientific research.
Alzheimer Disease/therapy* ; Humans ; Ion Channels/physiology* ; Oxidative Stress ; Animals ; Amyloid beta-Peptides/metabolism* ; Synaptic Transmission ; Calcium/metabolism*

OBJECTIVE: To elucidate the modulation mechanism of Suanzaoren Decoction (SZRD) on basolateral amygdala (BLA) neuronal activity to alleviate chronic restraint stress (CRS)-related behavioral deficits. METHODS: The male C57BL/6J mice were assigned to 4 groups using the complete randomization method, including control (CON, n=19), CRS (n=19), SZRD (n=21), and fluoxetine (Flu, n=22) groups. Mice were restrained for 6 h per day, over a 21-d period to establish CRS models. The CON group remained in their cages without food or water during the 6-h matching period. SZRD and Flu groups received intragastric administration of SZRD (4.68 g/kg) and Flu (20 mg/kg) daily, respectively, 30 min before restraint for 21 consecutive days. The therapeutic effects of SZRD were evaluated using behavioral tests including the tail suspension test, elevated plus maze test, and forced swimming test. The cellular Fletcher B. Judson murine osteosarcoma proto-oncogene (c-Fos) expression in the BLA was measured using immunofluorescence, while action potential (AP) firing and synaptic transmission in BLA pyramidal neurons were evaluated using whole-cell patch-clamp recordings. RESULTS: SZRD administration significantly increased time spent in the open arms and open-arm entries while reducing immobility time (P<0.05 or P<0.01). It downregulated CRS-induced c-Fos expression and AP firing of pyramidal neurons in the BLA (P<0.01). Additionally, SZRD selectively attenuated excitatory (P<0.01), but not inhibitory, synaptic transmission onto BLA pyramidal neurons. CONCLUSION SZRD alleviated CRS-induced anxiety- and depression-like behaviors in mice by modulating the excitability and synaptic transmission of BLA pyramidal neurons.
Animals ; Drugs, Chinese Herbal/therapeutic use* ; Depression/complications* ; Pyramidal Cells/pathology* ; Male ; Mice, Inbred C57BL ; Basolateral Nuclear Complex/pathology* ; Restraint, Physical ; Anxiety/complications* ; Behavior, Animal/drug effects* ; Stress, Psychological/physiopathology* ; Mice ; Proto-Oncogene Proteins c-fos/metabolism* ; Action Potentials/drug effects* ; Synaptic Transmission/drug effects*

OBJECTIVES: To investigate the mechanism by which the pyramidal neurons of the anterior cingulate cortex (ACC) modulate the effects of enriched environment (EE) for relieving anxiety-like behaviors in mice. METHODS: C57BL/6J mice were randomly divided into control group, restraint stress (RS) group, and RS+EE group (n=8). The mice in the latter two groups were subjected to RS for 2 h daily for 3 days, and those in RS+EE group were housed in an EE during modeling. Anxiety-like behaviors of the mice were evaluated using the elevated plus-maze tests (EPM) and open field test (OFT). Changes in c-Fos expression in the ACC of the mice were detected with immunofluorescence assay, and pyramidal neuron excitability in the ACC (Pyn^ACC) was measured using patch-clamp technique. The miniature excitatory and inhibitory postsynaptic currents (mEPSC and mIPSC, respectively) were analyzed to assess synaptic transmission changes. RESULTS: Behavioral tests showed obvious anxiety-like behaviors in RS mice, and such behavioral changes were significantly improved in RS+EE mice. Immunofluorescence staining revealed significantly increased c-Fos expression in the ACC in RS mice but lowered c-Fos expression in RS+EE group. Compared with the control mice, the RS mice showed increased action potential firing rate of Pyn^ACC, which was significantly reduced in RS+EE group. Compared with the RS mice, the RS+EE mice showed also decreased frequency of mEPSCs of Pyn^ACC, but the amplitude exhibited no significant changes. No obvious changes in the frequency or amplitude of mIPSCs were observed in RS+EE mice. CONCLUSIONS EE reduces excitability of Pyn^ACC to alleviate anxiety-like behaviors induced by RS in mice.
Animals ; Anxiety/physiopathology* ; Gyrus Cinguli ; Mice, Inbred C57BL ; Mice ; Pyramidal Cells/physiology* ; Restraint, Physical ; Stress, Psychological ; Proto-Oncogene Proteins c-fos/metabolism* ; Male ; Behavior, Animal ; Environment ; Excitatory Postsynaptic Potentials

Learning-associated functional plasticity at hippocampal synapses remains largely unexplored. Here, in a single session of reward-based trace conditioning, we examine learning-induced synaptic plasticity in the dorsal CA1 hippocampus (dCA1). Local field-potential recording combined with selective optogenetic inhibition first revealed an increase of dCA1 synaptic responses to the conditioned stimulus (CS) induced during conditioning at both Schaffer collaterals to the stratum radiatum (Rad) and temporoammonic input to the lacunosum moleculare (LMol). At these dCA1 inputs, synaptic potentiation of CS-responding excitatory synapses was further demonstrated by locally blocking NMDA receptors during conditioning and whole-cell recording sensory-evoked synaptic responses in dCA1 neurons from naive animals. An overall similar time course of the induction of synaptic potentiation was found in the Rad and LMol by multiple-site recording; this emerged later and saturated earlier than conditioned behavioral responses. Our experiments demonstrate a cued memory-associated dCA1 synaptic plasticity induced at both Schaffer collaterals and temporoammonic pathways.
Animals ; CA1 Region, Hippocampal/physiology* ; Male ; Association Learning/physiology* ; Neuronal Plasticity/physiology* ; Cues ; Memory/physiology* ; Synapses/physiology* ; Conditioning, Classical/physiology* ; Excitatory Postsynaptic Potentials/physiology* ; Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors* ; Rats ; Optogenetics

Epilepsy is a chronic neurological disorder affecting ~65 million individuals worldwide. Abnormal synaptic plasticity is one of the most important pathological features of this condition. We investigated how ubiquitin-specific peptidase 47 (USP47) influences synaptic plasticity and its link to epilepsy. We found that USP47 enhanced excitatory postsynaptic transmission and increased the density of total dendritic spines and the proportion of mature dendritic spines. Furthermore, USP47 inhibited the degradation of the ubiquitinated α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunit glutamate receptor 1 (GluR1), which is associated with synaptic plasticity. In addition, elevated levels of USP47 were found in epileptic mice, and USP47 knockdown reduced the frequency and duration of seizure-like events and alleviated epileptic seizures. To summarize, we present a new mechanism whereby USP47 regulates excitatory postsynaptic plasticity through the inhibition of ubiquitinated GluR1 degradation. Modulating USP47 may offer a potential approach for controlling seizures and modifying disease progression in future therapeutic strategies.
Animals ; Receptors, AMPA/metabolism* ; Neuronal Plasticity/physiology* ; Seizures/physiopathology* ; Disease Models, Animal ; Mice, Inbred C57BL ; Mice ; Ubiquitin Thiolesterase/genetics* ; Male ; Excitatory Postsynaptic Potentials/physiology* ; Ubiquitination ; Dendritic Spines/metabolism* ; Hippocampus/metabolism*

Neuronomodulation refers to the modulation of neural conduction and synaptic transmission (i.e., the conduction process involved in synaptic transmission) of excitable neurons via changes in the membrane potential in response to chemical substances, from spillover neurotransmitters to paracrine or endocrine hormones circulating in the blood. Neuronomodulation can be direct or indirect, depending on the transduction pathways from the ligand binding site to the ion pore, either on the same molecule, i.e. the ion channel, or through an intermediate step on different molecules. The major players in direct neuronomodulation are ligand-gated or voltage-gated ion channels. The key process of direct neuronomodulation is the binding and chemoactivation of ligand-gated or voltage-gated ion channels, either orthosterically or allosterically, by various ligands. Indirect neuronomodulation involves metabotropic receptor-mediated slow potentials, where steroid hormones, cytokines, and chemokines can implement these actions. Elucidating neuronomodulation is of great significance for understanding the physiological mechanisms of brain function, and the occurrence and treatment of diseases.
Ligands ; Neurons/metabolism* ; Synaptic Transmission/physiology* ; Ion Channels/metabolism* ; Hormones/metabolism*

The CC chemokine ligand 2 (CCL2, also known as MCP-1) and its cognate receptor CCR2 have well-characterized roles in chemotaxis. CCL2 has been previously shown to promote excitatory synaptic transmission and neuronal excitability. However, the detailed molecular mechanism underlying this process remains largely unclear. In cultured hippocampal neurons, CCL2 application rapidly upregulated surface expression of GluA1, in a CCR2-dependent manner, assayed using SEP-GluA1 live imaging, surface GluA1 antibody staining, and electrophysiology. Using pharmacology and reporter assays, we further showed that CCL2 upregulated surface GluA1 expression primarily via Gα_q- and CaMKII-dependent signaling. Consistently, using i.p. injection of lipopolysaccharide to induce neuroinflammation, we found upregulated phosphorylation of S831 and S845 sites on AMPA receptor subunit GluA1 in the hippocampus, an effect blocked in Ccr2^-/- mice. Together, these results provide a mechanism through which CCL2, and other secreted molecules that signal through G-protein coupled receptors, can directly regulate synaptic transmission.
Animals ; Receptors, AMPA/metabolism* ; Chemokine CCL2/metabolism* ; Hippocampus/drug effects* ; Neurons/drug effects* ; Synaptic Transmission/drug effects* ; Mice ; Receptors, CCR2/metabolism* ; Protein Transport/drug effects* ; Mice, Inbred C57BL ; Cells, Cultured ; Mice, Knockout ; Excitatory Postsynaptic Potentials/drug effects* ; Rats

Chronic pain is challenging to treat due to the limited therapeutic options and adverse side-effects of therapies. Astrocytes are the most abundant glial cells in the central nervous system and play important roles in different pathological conditions, including chronic pain. Astrocytes regulate nociceptive synaptic transmission and network function via neuron-glia and glia-glia interactions to exaggerate pain signals under chronic pain conditions. It is also becoming clear that astrocytes play active roles in brain regions important for the emotional and memory-related aspects of chronic pain. Therefore, this review presents our current understanding of the roles of astrocytes in chronic pain, how they regulate nociceptive responses, and their cellular and molecular mechanisms of action.
Humans ; Astrocytes/pathology* ; Chronic Pain/pathology* ; Neuroglia/physiology* ; Neurons/physiology* ; Synaptic Transmission ; Chronic Disease

Effective treatments for neuropathic pain are lacking due to our limited understanding of the mechanisms. The circRNAs are mainly enriched in the central nervous system. However, their function in various physiological and pathological conditions have yet to be determined. Here, we identified circFhit, an exon-intron circRNA expressed in GABAergic neurons, which reduced the inhibitory synaptic transmission in the spinal dorsal horn to mediate spared nerve injury-induced neuropathic pain. Moreover, we found that circFhit decreased the expression of GAD65 and induced hyperexcitation in NK1R⁺ neurons by promoting the expression of its parental gene Fhit in cis. Mechanistically, circFhit was directly bound to the intronic region of Fhit, and formed a circFhit/HNRNPK complex to promote Pol II phosphorylation and H2B monoubiquitination by recruiting CDK9 and RNF40 to the Fhit intron. In summary, we revealed that the exon-intron circFhit contributes to GABAergic neuron-mediated NK1R⁺ neuronal hyperexcitation and neuropathic pain via regulating Fhit in cis.
Rats ; Animals ; Posterior Horn Cells/pathology* ; Spinal Cord Dorsal Horn/metabolism* ; Neuralgia ; Synaptic Transmission

Acetylcholine (ACh) is an important neuromodulator in various cognitive functions. However, it is unclear how ACh influences neural circuit dynamics by altering cellular properties. Here, we investigated how ACh influences reverberatory activity in cultured neuronal networks. We found that ACh suppressed the occurrence of evoked reverberation at low to moderate doses, but to a much lesser extent at high doses. Moreover, high doses of ACh caused a longer duration of evoked reverberation, and a higher occurrence of spontaneous activity. With whole-cell recording from single neurons, we found that ACh inhibited excitatory postsynaptic currents (EPSCs) while elevating neuronal firing in a dose-dependent manner. Furthermore, all ACh-induced cellular and network changes were blocked by muscarinic, but not nicotinic receptor antagonists. With computational modeling, we found that simulated changes in EPSCs and the excitability of single cells mimicking the effects of ACh indeed modulated the evoked network reverberation similar to experimental observations. Thus, ACh modulates network dynamics in a biphasic fashion, probably by inhibiting excitatory synaptic transmission and facilitating neuronal excitability through muscarinic signaling pathways.
Cholinergic Agents/pharmacology* ; Acetylcholine/metabolism* ; Neurons/metabolism* ; Synaptic Transmission/physiology*