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European Journal of Pharmacology Jun 2024Nicotine has been shown to enhance object recognition memory in the novel object recognition (NOR) test by activating excitatory neurons in the medial prefrontal cortex...
Nicotine has been shown to enhance object recognition memory in the novel object recognition (NOR) test by activating excitatory neurons in the medial prefrontal cortex (mPFC). However, the exact neuronal mechanisms underlying the nicotine-induced activation of mPFC neurons and the resultant memory enhancement remain poorly understood. To address this issue, we performed brain-slice electrophysiology and the NOR test in male C57BL/6J mice. Whole-cell patch-clamp recordings from layer V pyramidal neurons in the mPFC revealed that nicotine augments the summation of evoked excitatory postsynaptic potentials (eEPSPs) and that this effect was suppressed by N-[3,5-Bis(trifluoromethyl)phenyl]-N'-[2,4-dibromo-6-(2H-tetrazol-5-yl)phenyl]urea (NS5806), a voltage-dependent potassium (Kv) 4.3 channel activator. In line with these findings, intra-mPFC infusion of NS5806 suppressed systemically administered nicotine-induced memory enhancement in the NOR test. Additionally, miRNA-mediated knockdown of Kv4.3 channels in mPFC pyramidal neurons enhanced object recognition memory. Furthermore, inhibition of A-type Kv channels by intra-mPFC infusion of 4-aminopyridine was found to enhance object recognition memory, while this effect was abrogated by prior intra-mPFC NS5806 infusion. These results suggest that nicotine augments the summation of eEPSPs via the inhibition of Kv4.3 channels in mPFC layer V pyramidal neurons, resulting in the enhancement of object recognition memory.
PubMed: 38942263
DOI: 10.1016/j.ejphar.2024.176790 -
Biomedicine & Pharmacotherapy =... Jun 2024Alzheimer's disease (AD) is characterized by cognitive impairment, loss of learning and memory, and abnormal behaviors. Scopolamine (SCOP) is a non-selective antagonist...
Ameliorative effect of vanillic acid against scopolamine-induced learning and memory impairment in rat via attenuation of oxidative stress and dysfunctional synaptic plasticity.
Alzheimer's disease (AD) is characterized by cognitive impairment, loss of learning and memory, and abnormal behaviors. Scopolamine (SCOP) is a non-selective antagonist of muscarinic acetylcholine receptors that exhibits the behavioral and molecular hallmarks of AD. Vanillic acid (VA), a phenolic compound, is obtained from the roots of a traditional plant called Angelica sinensis, and has several pharmacologic effects, including antimicrobial, anti-inflammatory, anti-angiogenic, anti-metastatic, and antioxidant properties. Nevertheless, VA's neuroprotective potential associated with the memory has not been thoroughly investigated. Therefore, this study investigated whether VA treatment has an ameliorative effect on the learning and memory impairment induced by SCOP in rats. Behavioral experiments were utilized to assess the learning and memory performance associated with the hippocampus. Using western blotting analysis and assay kits, the neuronal damage, oxidative stress, and acetylcholinesterase activity responses of hippocampus were evaluated. Additionally, the measurement of long-term potentiation was used to determine the function of synaptic plasticity in organotypic hippocampal slice cultures. In addition, the synaptic vesicles' density and the length and width of the postsynaptic density were evaluated using electron microscopy. Consequently, the behavioral, biochemical, electrophysiological, and ultrastructural analyses revealed that VA treatment prevents learning and memory impairments caused by SCOP in rats. The study's findings suggest that VA has a neuroprotective effect on SCOP-induced learning and memory impairment linked to the hippocampal cholinergic system, oxidative damage, and synaptic plasticity. Therefore, VA may be a prospective therapeutic agent for treating AD.
PubMed: 38941895
DOI: 10.1016/j.biopha.2024.117000 -
Journal of Comparative Physiology. A,... Jun 2024Evidence has been accumulating that elements of the vertebrate pituitary adenylate cyclase-activating polypeptide (PACAP) system are missing in non-chordate genomes,...
Evidence has been accumulating that elements of the vertebrate pituitary adenylate cyclase-activating polypeptide (PACAP) system are missing in non-chordate genomes, which is at odds with the partial sequence-, immunohistochemical-, and physiological data in the literature. Multilevel experiments were performed on the great pond snail (Lymnaea stagnalis) to explore the role of PACAP in invertebrates. Screening of neuronal transcriptome and genome data did not reveal homologs to the elements of vertebrate PACAP system. Despite this, immunohistochemical investigations with an anti-human PAC receptor antibody yielded a positive signal in the neuronal elements in the heart. Although Western blotting of proteins extracted from the nervous system found a relevant band for PACAP-38, immunoprecipitation and mass spectrometric analyses revealed no corresponding peptide fragments. Similarly to the effects reported in vertebrates, PACAP-38 significantly increased cAMP synthesis in the heart and had a positive ionotropic effect on heart preparations. Moreover, it significantly modulated the effects of serotonin and acetylcholine. Homologs to members of Cluster B receptors, which have shared common evolutionary origin with the vertebrate PACAP receptors, PTHRs, and GCGRs, were identified and shown not to be expressed in the heart, which does not support a potential role in the mediation of PACAP-induced effects. Our findings support the notion that the PACAP system emerged after the protostome-deuterostome divergence. Using antibodies against vertebrate proteins is again highlighted to have little/no value in invertebrate studies. The physiological effects of vertebrate PACAP peptides in protostomes, no matter how similar they are to those in vertebrates, should be considered non-specific.
PubMed: 38940930
DOI: 10.1007/s00359-024-01706-5 -
Central Nervous System Agents in... Jun 2024More than 20 million people worldwide have Alzheimer's disease (AD), making it the most prevalent disease. Patients with AD may live for at least a decade after...
More than 20 million people worldwide have Alzheimer's disease (AD), making it the most prevalent disease. Patients with AD may live for at least a decade after diagnosis, making it the most common cause of disability in the elderly. Each year, 1% to 4% of the population is affected by AD, with prevalence peaking between ages 65 and 70 and declining to 6% among those over 85. Researchers have accumulated evidence on medicinal herbs that may reverse the pathogenesis of Alzheimer's disease. Alzheimer's disease (AD) is associated with severe memory loss, which can negatively impact social and professional life. The first neurotransmitter linked to Alzheimer's was acetylcholine (ACh). There is no known cure, and the available treatments are ineffective. Multiple studies indicate that Ayurvedic restorative herbs and their constituents may be effective in treating Alzheimer's disease. This technique emphasizes the fact that delaying or preventing Alzheimer's disease with the help of natural bio-actives could reduce the number of cases over the next half-century. To provide detailed information, the pathology and pathophysiology of Alzheimer's Disease are discussed in the text of this review, along with an overview of the neurotransmitters involved in the progression of the disease. The importance of different natural bioactives for the treatment of Alzheimer's disease is also outlined in the paper. The information contained in this paper can serve as a template for future research expressing the more beneficial role of other bioactive in acting as an adjuvant in the prevention and treatment of this disease, facing certain challenges and gaps with conventional drugs used to treat Alzheimer's disease.
PubMed: 38939998
DOI: 10.2174/0118715249307525240614073143 -
Case Reports in Neurological Medicine 2024Myasthenic crises (MC) are potentially life-threatening acute exacerbations of myasthenia gravis (MG) characterized by profound muscle weakness, bulbar symptoms, and...
Myasthenic crises (MC) are potentially life-threatening acute exacerbations of myasthenia gravis (MG) characterized by profound muscle weakness, bulbar symptoms, and potential for respiratory failure. Intravenous immunoglobulins (IVIG) and plasma exchange (PLEX) are conventional treatments for myasthenic exacerbations. Recently, new therapeutic options for generalized acetylcholine-receptor antibody positive (AchR+) MG were approved as an add-on therapy. They mainly consist of complement C5 inhibitors such as eculizumab and ravulizumab and neonatal Fc receptor antagonists such as efgartigimod with the approval of more options pending, e.g., zilucoplan and rozanolixizumab. More therapeutic options are in the pipeline. Although the data show a quick and reliable treatment response, these medications have not been studied for the therapy of myasthenic crisis. We present the case of a 57-year-old male with his first episode of generalized myasthenia gravis (MG) and positive acetylcholine-receptor antibodies (AchR+) who was transferred to our neurological intensive care unit with worsening generalized weakness, dysphagia, and respiratory distress. The crisis was triggered by pneumonia due to dysphagia. He was diagnosed with myasthenic crisis and treated with intravenous pyridostigmine, plasmapheresis (PLEX), and continued prednisone. Initial improvement was followed by deterioration, requiring readmission and additional PLEX. After a further decline, efgartigimod was administered, leading to significant improvement within 48 hours, as evidenced by reduced MG-ADL and QMG scores. The patient continued to improve and was stable enough for transfer to a rehabilitation facility. This case illustrates the potential of efgartigimod as a novel treatment for refractory myasthenic crises.
PubMed: 38939234
DOI: 10.1155/2024/9455237 -
Journal of Molecular Modeling Jun 2024Existing researches confirmed that β amyloid (Aβ) has a high affinity for the α7 nicotinic acetylcholine receptor (α7nAChR), associating closely to Alzheimer's...
CONTEXT
Existing researches confirmed that β amyloid (Aβ) has a high affinity for the α7 nicotinic acetylcholine receptor (α7nAChR), associating closely to Alzheimer's disease. The majority of related studies focused on the experimental reports on the neuroprotective role of Aβ fragment (Aβ), however, with a lack of investigation into the most suitable binding region and mechanism of action between Aβ fragment and α7nAChR. In the study, we employed four Aβ fragments Aβ, Aβ, Aβ, Aβ, and Aβ, of which the first three were confirmed to play neuroprotective roles upon directly binding, to interact with α7nAChR.
METHODS
The protein-ligand docking server of CABS-DOCK was employed to obtain the α7nAChR-Aβ complexes. Only the top α7nAChR-Aβ complexes were used to perform all-atom GROMACS dynamics simulation in combination with Charmm36 force field, by which α7nAChR-Aβ interactions' dynamic behavior and specific locations of these different Aβ fragments were identified. MM-PBSA calculations were also done to estimate the binding free energies and the different contributions from the residues in the Aβ. Two distinct results for the first three and fourth Aβ fragments in binding site, strength, key residue, and orientation, account for why the fourth fails to play a neuroprotective role at the molecular level.
Topics: Amyloid beta-Peptides; alpha7 Nicotinic Acetylcholine Receptor; Molecular Dynamics Simulation; Peptide Fragments; Protein Binding; Humans; Molecular Docking Simulation; Binding Sites; Ligands
PubMed: 38937296
DOI: 10.1007/s00894-024-06032-w -
Neuroreport Jun 2024Neuromuscular junctions are innervated by motor and sympathetic nerves. The sympathetic modulation of motor innervation shows functional decline during aging, but the...
Identification of adrenergic presynaptic and postsynaptic protein locations at neuromuscular junctions, their decrease during aging, and recovery by nicotinamide mononucleotide administration.
Neuromuscular junctions are innervated by motor and sympathetic nerves. The sympathetic modulation of motor innervation shows functional decline during aging, but the cellular and molecular mechanism of this change is not fully known. This study aimed to evaluate the effect of aging on sympathetic nerves and synaptic proteins at mouse neuromuscular junctions. Sympathetic nerves, presynaptic, and postsynaptic proteins of sympathetic nerves at neuromuscular junctions were visualized using immunohistochemistry, and aging-related changes were compared between adult-, aged-, and nicotinamide mononucleotide (NMN) administered aged mice. Sympathetic nerves were detected by anti-tyrosine hydroxylase antibody, and presynaptic protein vesicular monoamine transporter 2 colocalized with the sympathetic nerves. These two signals surrounded motor nerve terminals and acetylcholine receptor clusters. Postsynaptic neurotransmitter receptor β2-adrenergic receptors colocalized with motor nerve terminals and resided in reduced density at extrasynaptic sarcolemma. The signal intensity of the sympathetic nerve marker did not show a significant difference at neuromuscular junctions between 8.5-month-old adult mice and 25-month-old aged mice. However, the signal intensity of vesicular monoamine transporter 2 and β2-adrenergic receptors showed age-related decline at neuromuscular junctions. Interestingly, both age-related declines reverted to the adult level after 1 month of oral administration of NMN by drinking water. In contrast, NMN administration did not alter the expression level of sympathetic marker tyrosine hydroxylase at neuromuscular junctions. The results suggest a functional decline of sympathetic nerves at aged neuromuscular junctions due to decreases in presynaptic and postsynaptic proteins, which can be reverted to the adult level by NMN administration.
PubMed: 38935067
DOI: 10.1097/WNR.0000000000002070 -
Development (Cambridge, England) Jun 2024Spermatogonial stem cells (SSCs) undergo self-renewal division to sustain spermatogenesis. Although it is possible to derive SSC cultures in most mouse strains, SSCs...
Spermatogonial stem cells (SSCs) undergo self-renewal division to sustain spermatogenesis. Although it is possible to derive SSC cultures in most mouse strains, SSCs from a 129 background never proliferate under the same culture conditions, suggesting they have distinct self-renewal requirements. Here, we established long-term culture conditions for SSCs from mice of the 129 background (129 mice). An analysis of 129 testes showed significant reduction of GDNF and CXCL12, whereas FGF2, INHBA and INHBB were higher than in testes of C57BL/6 mice. An analysis of undifferentiated spermatogonia in 129 mice showed higher expression of Chrna4, which encodes an acetylcholine (Ach) receptor component. By supplementing medium with INHBA and Ach, SSC cultures were derived from 129 mice. Following lentivirus transduction for marking donor cells, transplanted cells re-initiated spermatogenesis in infertile mouse testes and produced transgenic offspring. These results suggest that the requirements of SSC self-renewal in mice are diverse, which has important implications for understanding self-renewal mechanisms in various animal species.
Topics: Animals; Male; Mice; Spermatogonia; Mice, Inbred C57BL; Spermatogenesis; Testis; Cell Self Renewal; Adult Germline Stem Cells; Cells, Cultured; Receptors, Nicotinic; Mice, Inbred Strains; Cell Differentiation; Cell Proliferation; Stem Cells; Mice, Transgenic
PubMed: 38934417
DOI: 10.1242/dev.202553 -
Arteriosclerosis, Thrombosis, and... Jun 2024
PubMed: 38934116
DOI: 10.1161/ATVBAHA.124.320916 -
International Journal of Molecular... Jun 2024is an essential species for freshwater economic aquaculture in China, but in the larval process, their salinity requirement is high, which leads to salinity stress in...
is an essential species for freshwater economic aquaculture in China, but in the larval process, their salinity requirement is high, which leads to salinity stress in the water. In order to elucidate the mechanisms regulating the response of to acute low-salinity exposure, we conducted a comprehensive study of the response of exposed to different salinities' (0‱, 6‱, and 12‱) data for 120 h. The activities of catalase, superoxide dismutase, and glutathione peroxidase were found to be significantly inhibited in the hepatopancreas and muscle following low-salinity exposure, resulting in oxidative damage and immune deficits in . Differential gene enrichment in transcriptomics indicated that low-salinity stress induced metabolic differences and immune and inflammatory dysfunction in . The differential expressions of , , and genes indicated the inhibition of growth, development, and molting ability of . At the proteomic level, low salinity induced metabolic differences and affected biological and cellular regulation, as well as the immune response. Tyramine, trans-1,2-Cyclohexanediol, sorbitol, acetylcholine chloride, and chloroquine were screened by metabolomics as differential metabolic markers. In addition, combined multi-omics analysis revealed that metabolite chloroquine was highly correlated with low-salt stress.
Topics: Animals; Palaemonidae; Larva; Salt Stress; Transcriptome; Proteomics; Salinity; Gene Expression Profiling; Metabolomics; Oxidative Stress; Multiomics
PubMed: 38928514
DOI: 10.3390/ijms25126809