-
Epilepsy Research May 2024The hyperpolarization-activated cyclic nucleotide-gated cation channel (HCN1) is predominantly located in key regions associated with epilepsy, such as the neocortex and...
BACKGROUND
The hyperpolarization-activated cyclic nucleotide-gated cation channel (HCN1) is predominantly located in key regions associated with epilepsy, such as the neocortex and hippocampus. Under normal physiological conditions, HCN1 plays a crucial role in the excitatory and inhibitory regulation of neuronal networks. In temporal lobe epilepsy, the expression of HCN1 is decreased in the hippocampi of both animal models and patients. However, whether HCN1 expression changes during epileptogenesis preceding spontaneous seizures remains unclear.
OBJECTIVE
The aim of this study was to determine whether the expression of HCN1 is altered during the epileptic prodromal phase, thereby providing evidence for its role in epileptogenesis.
METHODS
We utilized a cobalt wire-induced rat epilepsy model to observe changes in HCN1 during epileptogenesis and epilepsy. Additionally, we also compared HCN1 alterations in epileptogenic tissues between cobalt wire- and pilocarpine-induced epilepsy rat models. Long-term video EEG recordings were used to confirm seizures development. Transcriptional changes, translation, and distribution of HCN1 were assessed using high-throughput transcriptome sequencing, total protein extraction, membrane and cytoplasmic protein fractionation, western blotting, immunohistochemistry, and immunofluorescence techniques.
RESULTS
In the cobalt wire-induced rat epilepsy model during the epileptogenesis phase, total HCN1 mRNA and protein levels were downregulated. Specifically, the membrane expression of HCN1 was decreased, whereas cytoplasmic HCN1 expression showed no significant change. The distribution of HCN1 in the distal dendrites of neurons decreased. During the epilepsy period, similar HCN1 alterations were observed in the neocortex of rats with cobalt wire-induced epilepsy and hippocampus of rats with lithium pilocarpine-induced epilepsy, including downregulation of mRNA levels, decreased total protein expression, decreased membrane expression, and decreased distal dendrite expression.
CONCLUSIONS
Alterations in HCN1 expression and distribution are involved in epileptogenesis beyond their association with seizure occurrence. Similarities in HCN1 alterations observed in epileptogenesis-related tissues from different models suggest a shared pathophysiological pathway in epileptogenesis involving HCN1 dysregulation. Therefore, the upregulation of HCN1 expression in neurons, maintenance of the HCN1 membrane, and distal dendrite distribution in neurons may represent promising disease-modifying strategies in epilepsy.
Topics: Animals; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; Male; Epilepsy; Rats, Sprague-Dawley; Rats; Hippocampus; Disease Models, Animal; Potassium Channels; Pilocarpine; Cobalt; Electroencephalography; Neurons; Neocortex
PubMed: 38555654
DOI: 10.1016/j.eplepsyres.2024.107355 -
International Journal of Molecular... May 2023In mice, the contraction of the ciliary muscle via the administration of pilocarpine reduces the zonular tension applied to the lens and activates the TRPV1-mediated arm...
In mice, the contraction of the ciliary muscle via the administration of pilocarpine reduces the zonular tension applied to the lens and activates the TRPV1-mediated arm of a dual feedback system that regulates the lens' hydrostatic pressure gradient. In the rat lens, this pilocarpine-induced reduction in zonular tension also causes the water channel AQP5 to be removed from the membranes of fiber cells located in the anterior influx and equatorial efflux zones. Here, we determined whether this pilocarpine-induced membrane trafficking of AQP5 is also regulated by the activation of TRPV1. Using microelectrode-based methods to measure surface pressure, we found that pilocarpine also increased pressure in the rat lenses via the activation of TRPV1, while pilocarpine-induced removal of AQP5 from the membrane observed using immunolabelling was abolished by pre-incubation of the lenses with a TRPV1 inhibitor. In contrast, mimicking the actions of pilocarpine by blocking TRPV4 and then activating TRPV1 resulted in sustained increase in pressure and the removal of AQP5 from the anterior influx and equatorial efflux zones. These results show that the removal of AQP5 in response to a decrease in zonular tension is mediated by TRPV1 and suggest that regional changes to P contribute to lens hydrostatic pressure gradient regulation.
Topics: Rats; Mice; Animals; Pilocarpine; Lens, Crystalline; Aquaporins; Membranes; Aquaporin 5; TRPV Cation Channels
PubMed: 37240426
DOI: 10.3390/ijms24109080 -
Biochemistry and Biophysics Reports Mar 2021Epilepsy is a neurological disorder of genetic or environmental origin characterized by recurrent spontaneous seizures. A rodent model of temporal lobe epilepsy is...
Epilepsy is a neurological disorder of genetic or environmental origin characterized by recurrent spontaneous seizures. A rodent model of temporal lobe epilepsy is induced by a single administration of pilocarpine, a non-selective cholinergic muscarinic receptor agonist. The molecular changes associated with pilocarpine-induced seizures are still poorly described. Epigenetic multiprotein complexes that regulate gene expression by changing the structure of chromatin impose transcriptional memories. Among the epigenetic enzymes relevant to the epileptogenic process is lysine-specific demethylase 1 (LSD1, KDM1A), which regulates the expression of genes that control neuronal excitability. LSD1 forms complexes with the CoREST family of transcriptional corepressors, which are molecular bridges that bring HDAC1/2 and LSD1 enzymes to deacetylate and demethylate the tail of nucleosomal histone H3. To test the hypothesis that LSD1-complexes are involved in initial modifications associated with pilocarpine-induced epilepsy, we studied the expression of main components of LSD1-complexes and the associated epigenetic marks on isolated neurons and the hippocampus of pilocarpine-treated mice. Using a single injection of 300 mg/kg of pilocarpine and after 24 h, we found that protein levels of LSD1, CoREST2, and HDAC1/2 increased, while CoREST1 decreased in the hippocampus. In addition, we observed increased histone H3 lysine 9 di- and trimethylation (H3K9me2/3) and decreased histone H3 lysine 4 di and trimethylation (H3K4me2/3). Similar findings were observed in cultured hippocampal neurons and HT-22 hippocampal cell line treated with pilocarpine. In conclusion, our data show that muscarinic receptor activation by pilocarpine induces a global repressive state of chromatin and prevalence of LSD1-CoREST2 epigenetic complexes, modifications that could underlie the pathophysiological processes leading to epilepsy.
PubMed: 33426312
DOI: 10.1016/j.bbrep.2020.100889 -
Nature Neuroscience Jan 2021Microglial surveillance is a key feature of brain physiology and disease. Here, we found that G-dependent microglial dynamics prevent neuronal network hyperexcitability....
Microglial surveillance is a key feature of brain physiology and disease. Here, we found that G-dependent microglial dynamics prevent neuronal network hyperexcitability. By generating Mg mice to genetically inhibit G in microglia, we show that sustained reduction of microglia brain surveillance and directed process motility induced spontaneous seizures and increased hypersynchrony after physiologically evoked neuronal activity in awake adult mice. Thus, G-dependent microglia dynamics may prevent hyperexcitability in neurological diseases.
Topics: Animals; Calcium Signaling; Cell Movement; Convulsants; Electroencephalography; G-Protein-Coupled Receptor Kinase 1; Immunologic Surveillance; Mice; Microglia; Nerve Net; Nervous System Diseases; Nervous System Physiological Phenomena; Pilocarpine; Seizures; Signal Transduction; rho GTP-Binding Proteins
PubMed: 33318667
DOI: 10.1038/s41593-020-00756-7 -
Molecules (Basel, Switzerland) Nov 2021Chondroitin sulfate is a proteoglycan component of the extracellular matrix (ECM) that supports neuronal and non-neuronal cell activity, provides a negative domain to...
Chondroitin sulfate is a proteoglycan component of the extracellular matrix (ECM) that supports neuronal and non-neuronal cell activity, provides a negative domain to the extracellular matrix, regulates the intracellular positive ion concentration, and maintains the hypersynchronous epileptiform activity. Therefore, the present study hypothesized an antiepileptic potential of chondroitin sulfate (CS) in pentylenetetrazole-induced kindled epilepsy and pilocarpine-induced status epilepticus in mice. Levels of various oxidative stress markers and inflammatory mediators were estimated in the brain tissue homogenate of mice, and histopathological changes were evaluated. Treatment with valproate (110 mg/kg; i.p.) as a standard drug and chondroitin sulfate (100 & 200 mg/kg, p.o.) significantly ( < 0.01) and dose-dependently prevented the severity of kindled and spontaneous recurrent seizures in mice. Additionally, chondroitin sulfate showed its antioxidant potential by restoring the various biochemical levels and anti-inflammatory properties by reducing NF-kB levels and pro-inflammatory mediators like TNF-alpha, IL-1β, and IL-6, indicating the neuroprotective effect as well as the suppressed levels of caspase-3, which indicated a neuroprotective treatment strategy in epilepsy. The proteoglycan chondroitin sulfate restores the normal physiology and configuration of the neuronal tissue. Further, the molecular docking of chondroitin sulfate at the active pockets of TNF-alpha, IL-1β, and IL-6 showed excellent interactions with critical amino acid residues. In conclusion, the present work provides preclinical evidence of chondroitin sulfate as a new therapeutic approach in attenuating and preventing seizures with a better understanding of the mechanism of alteration in ECM changes influencing abnormal neuronal activities.
Topics: Animals; Anticonvulsants; Chondroitin Sulfates; Male; Mice; Molecular Docking Simulation; Neuroprotective Agents; Oxidative Stress; Pentylenetetrazole; Pilocarpine; Seizures; Status Epilepticus; Valproic Acid
PubMed: 34833865
DOI: 10.3390/molecules26226773 -
Ophthalmic Surgery, Lasers & Imaging... Jul 2022Vuity (pilocarpine HCL ophthalmic 1.25%) was approved for the treatment of presbyopia in October 2021. Previous case series have reported the presence of vitreofoveal...
Vuity (pilocarpine HCL ophthalmic 1.25%) was approved for the treatment of presbyopia in October 2021. Previous case series have reported the presence of vitreofoveal traction and retinal detachment following pilocarpine administration, but this was not reported in the recent randomized control trials assessing the efficacy of Vuity. The authors report a case of a woman of 65 years who developed vitreomacular traction immediately following the first administration of Vuity, review the literature, and present considerations regarding screening and management of patients starting Vuity. .
Topics: Female; Humans; Pilocarpine; Presbyopia; Retinal Diseases; Tomography, Optical Coherence; Traction; Vitreous Detachment
PubMed: 35858231
DOI: 10.3928/23258160-20220629-01 -
Neuroscience Sep 2022Synaptic vesicle glycoprotein 2A (SV2A) is a transmembrane protein that binds levetiracetam and is involved in neurotransmission via an unknown mechanism....
Synaptic vesicle glycoprotein 2A (SV2A) is a transmembrane protein that binds levetiracetam and is involved in neurotransmission via an unknown mechanism. SV2A-immunoreactivity is reduced in animal models of epilepsy, and in postmortem hippocampi from patients with temporal lobe epilepsy. It is not known if other regions outside the hippocampus are affected in epilepsy, and whether SV2A expression is permanently reduced or regulated over time. In this study, we induced a generalized status epilepticus (SE) by systemic administration of lithium-pilocarpine to adult female rats. The brains from all animals experiencing SE were collected at different time points after the treatment. The radiotracer, [C]-UCB-J, binds to SV2A with high affinity, and has been used for in vivo imaging as an a-proxy marker for synaptic density. Here we determined the level of tritiated UCB-J binding by semiquantitative autoradiography in the cerebral cortex, hippocampus, thalamus, and hypothalamus, and in cortical subregions. A prominent and highly significant reduction in SV2A binding capacity was observed over the first days after SE in the cerebral cortex and the hippocampus, but not in the thalamus and hypothalamus. The magnitude in reduction was larger and occurred earlier in the hippocampus and the piriform cortex, than in other cortical subregions. Interestingly, in all areas examined, the binding capacity returned to control levels 12 weeks after the SE comparable to the chronic epileptic phase. These data indicate that lithium-pilocarpine-induced epileptogenesis involves both loss and gain of synapses in the in a time-dependent manner.
Topics: Animals; Brain; Epilepsy; Female; Hippocampus; Lithium; Membrane Glycoproteins; Nerve Tissue Proteins; Pilocarpine; Rats; Status Epilepticus
PubMed: 35878719
DOI: 10.1016/j.neuroscience.2022.07.020 -
Epilepsy Research Jul 2022Recent studies have identified that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) exerts multiple functions besides its role in energy metabolism. It can form a...
Recent studies have identified that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) exerts multiple functions besides its role in energy metabolism. It can form a protein complex with GluA2 subunit of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs), translocate into nucleus and confer neurotoxicity in a cerebral ischemia model. We postulate that GAPDH may also induce neurotoxicity by forming a coupling with GluA2 in pilocarpine-induced epileptic model, and disruption of the GluA2/GAPDH coupling can protect against neuronal injury. In this study, induced status epilepticus (SE) in rats by the systemic administration of pilocarpine, collected hippocampal tissues at different time points after SE, and assessed the relationship between GluA2/GAPDH coupling and neuronal apoptosis in SE rats. Then, we interrupted the GluA2/GAPDH coupling by a special interfering peptide and determined whether neuronal injury can be rescued and hippocampus-depended memory function can be improved. We also evaluated the concentrations of GAPDH in nuclear and cytoplasmatic proteins in SE group, non-SE group and after interruption of GluA2/GAPDH coupling, to verify the nuclear translocation of GAPDH in SE model. We found that the apoptosis of hippocampal neurons was most significant at 72 h after SE, which was also the peak time of GluA2/GAPDH coupling expression and GluA2 consumption. After interruption of GluA2/GAPDH coupling, the apoptosis and memorial function of hippocampal neurons were improved and nuclear translocation of GluA2/GAPDH coupling was reduced. In conclusion, GAPDH can be translocated into nucleus in the form of GluA2/GAPDH, which plays an important role in regulating pilocarpine-induced epilepsy via neurotoxicity pathway.
Topics: Animals; Disease Models, Animal; Epilepsy; Glyceraldehyde-3-Phosphate Dehydrogenases; Hippocampus; Pilocarpine; Rats; Receptors, AMPA; Status Epilepticus
PubMed: 35636277
DOI: 10.1016/j.eplepsyres.2022.106945 -
European Archives of... Jul 2024This study aims to investigate the efficacy of lower dose pilocarpine in alleviating late dry mouth symptoms in head and neck cancer patients received radiotherapy.
Does lower dose pilocarpine have a role in radiation-induced xerostomia in the modern radiotherapy era? A single-center experience based on patient-reported outcome measures.
PURPOSE
This study aims to investigate the efficacy of lower dose pilocarpine in alleviating late dry mouth symptoms in head and neck cancer patients received radiotherapy.
METHODS
Eighteen head and neck cancer patients experiencing persistent dry mouth were enrolled in this study. All participants started pilocarpine treatment a median of 6 months post-radiotherapy. Initially, patients received pilocarpine at 5 mg/day, with a gradual increase to the recommended dose of 15 mg/day. A Patient-Reported Outcome Measurement (PROMs) questionnaire assessed symptoms' severity related to hyposalivation.
RESULTS
All patients reported symptomatic dry mouth above grade 2 before starting the medication. Pilocarpine treatment continued based on patients' self-assessment, with a median duration of 12 months (range, 3-36 months). The median daily maintenance dose was 10 mg (range, 5 to 20 mg). Total PROMs scores significantly decreased following medication, from 13 points (range 7-18 points) to 7 points (range 4-13 points) (p = 0.001). Significant improvements were observed in questions related to dry mouth (p < 0.001), water intake during eating (p = 0.01), carrying water (p = 0.01), taste (p < 0.001), and water intake during speech (p < 0.001). Initial and maintenance doses of pilocarpine were lower, and the duration of pilocarpine usage was shorter in patients treated with intensity-modulated radiation therapy compared to conformal radiotherapy (12 months vs. 25 months, p = 0.04).
CONCLUSION
Pilocarpine may be considered at doses lower for late-term dry mouth. With modern radiotherapy techniques effectively preserving the parotid gland, short-term use may be recommended in these patients. Future studies may enhance the development of a more robust patient selection criteria model.
Topics: Humans; Xerostomia; Pilocarpine; Male; Female; Middle Aged; Patient Reported Outcome Measures; Head and Neck Neoplasms; Aged; Muscarinic Agonists; Radiation Injuries; Adult; Treatment Outcome
PubMed: 38573515
DOI: 10.1007/s00405-024-08616-x -
Clinical and Experimental Pharmacology... Mar 2022Cardiac dysfunction is one of the leading causes of death in epilepsy. The anti-arrhythmic drug, amiodarone, is under investigation for its therapeutic effects in...
Cardiac dysfunction is one of the leading causes of death in epilepsy. The anti-arrhythmic drug, amiodarone, is under investigation for its therapeutic effects in epilepsy. We aimed to evaluate the possible effects of amiodarone on cardiac injury during status epilepticus, as it can cause prolongation of the QT interval. Five rat groups were enrolled in the study; three control groups (1) Control, (2) Control-lithium and (3) Control-Amio, treated with 150 mg/kg/intraperitoneal amiodarone, (4) Epilepsy model, induced by sequential lithium/pilocarpine administration, and (5) the epilepsy-Amio group. The model group expressed a typical clinical picture of epileptiform activity confirmed by the augmented electroencephalogram alpha and beta spikes. The anticonvulsive effect of amiodarone was prominent, it diminished (p < 0.001) the severity of seizures and hence, deaths and reduced serum noradrenaline levels. In the model group, the electrocardiogram findings revealed tachycardia, prolongation of the corrected QT (QTc) interval, depressed ST segments and increased myocardial oxidative stress. The in-vitro myocardial performance (contraction force and - (df/dt) ) was also reduced. Amiodarone decreased (p < 0.001) the heart rate, improved ST segment depression, and myocardial contractility with no significant change in the duration of the QTc interval. Amiodarone preserved the cardiac histological structure and reduced the myocardial injury markers represented by serum Troponin-I, oxidative stress and IL-1. Amiodarone pretreatment prevented the anticipated cardiac injury induced during epilepsy. Amiodarone possessed an anticonvulsive potential, protected the cardiac muscle and preserved its histological architecture. Therefore, amiodarone could be recommended as a protective therapy against cardiac dysfunction during epileptic seizures with favourable effect on seizure activity.
Topics: Adjuvants, Immunologic; Amiodarone; Animals; Anti-Arrhythmia Agents; Biomarkers; Epilepsy; Glutathione; Heart Diseases; Interleukin-1; Lithium Chloride; Male; Malondialdehyde; Muscarinic Agonists; Myocardial Contraction; Pilocarpine; Rats; Rats, Wistar; Superoxide Dismutase; Troponin I
PubMed: 34796981
DOI: 10.1111/1440-1681.13615