Schisandrin B, a dual positive allosteric modulator of GABAA and glycine receptors, alleviates seizures in multiple mouse models.

Epilepsy is a prevalent and severe neurological disorder and approximately 30% of patients are resistant to existing medications. It is of utmost importance to develop alternative therapies to treat epilepsy. Schisandrin B (SchB) is a major bioactive constituent of Schisandra chinensis (Turcz.) Baill and has multiple neuroprotective effects, sedative and hypnotic activities. In this study, we investigated the antiseizure effect of SchB in various mouse models of seizure and explored the underlying mechanisms. Pentylenetetrazole (PTZ), strychnine (STR), and pilocarpine-induced mouse seizure models were established. We showed that injection of SchB (10, 30, 60 mg/kg, i.p.) dose-dependently delayed the onset of generalized tonic-clonic seizures (GTCS), reduced the incidence of GTCS and mortality in PTZ and STR models. Meanwhile, injection of SchB (30 mg/kg, i.p.) exhibited therapeutic potential in pilocarpine-induced status epilepticus model, which was considered as a drug-resistant model. In whole-cell recording from CHO/HEK-239 cells stably expressing recombinant human GABAA receptors (GABAARs) and glycine receptors (GlyRs) and cultured hippocampal neurons, co-application of SchB dose-dependently enhanced GABA or glycine-induced current with EC50 values at around 5 µM, and application of SchB (10 µM) alone did not activate the channels in the absence of GABA or glycine. Furthermore, SchB (10 µM) eliminated both PTZ-induced inhibition on GABA-induced current (IGABA) and strychnine (STR)-induced inhibition on glycine-induced current (Iglycine). Moreover, SchB (10 µM) efficiently rescued the impaired GABAARs associated with genetic epilepsies. In addition, the homologous mutants in both GlyRs-α1(S267Q) and GABAARs-α1(S297Q)ß2(N289S)γ2L receptors by site-directed mutagenesis tests abolished SchB-induced potentiation of IGABA and Iglycine. In conclusion, we have identified SchB as a natural positive allosteric modulator of GABAARs and GlyRs, supporting its potential as alternative therapies for epilepsy.

Preclinical Assessment of a New Hybrid Compound C11 Efficacy on Neurogenesis and Cognitive Functions after Pilocarpine Induced Status Epilepticus in Mice.

Status epilepticus (SE) is a frequent medical emergency that can lead to a variety of neurological disorders, including cognitive impairment and abnormal neurogenesis. The aim of the presented study was the in vitro evaluation of potential neuroprotective properties of a new pyrrolidine-2,5-dione derivatives compound C11, as well as the in vivo assessment of the impact on the neurogenesis and cognitive functions of C11 and levetiracetam (LEV) after pilocarpine (PILO)-induced SE in mice. The in vitro results indicated a protective effect of C11 (500, 1000, and 2500 ng/mL) on astrocytes under trophic stress conditions in the MTT (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide) test. The results obtained from the in vivo studies, where mice 72 h after PILO SE were treated with C11 (20 mg/kg) and LEV (10 mg/kg), indicated markedly beneficial effects of C11 on the improvement of the neurogenesis compared to the PILO control and PILO LEV mice. Moreover, this beneficial effect was reflected in the Morris Water Maze test evaluating the cognitive functions in mice. The in vitro confirmed protective effect of C11 on astrocytes, as well as the in vivo demonstrated beneficial impact on neurogenesis and cognitive functions, strongly indicate the need for further advanced molecular research on this compound to determine the exact neuroprotective mechanism of action of C11.

Succinate accumulation induces mitochondrial reactive oxygen species generation and promotes status epilepticus in the kainic acid rat model.

Though succinate accumulation is associated with reactive oxygen species (ROS) production and neuronal injury, which play critical roles in epilepsy, it is unclear whether succinate accumulation contributes to the onset of epilepsy or seizures. We sought to investigate changes in succinate, oxidative stress, and mito-SOX levels, as well as mitophagy and neuronal change, in different status epilepticus (SE) rat models. Our results demonstrate that KA-induced SE was accompanied by increased levels of succinate, oxidative stress, and mito-SOX, as well as mitophagy and neuronal degeneration. The similarly increased levels of succinate, oxidative stress, and mito-SOX were also found in pilocarpine-induced SE. Moreover, the reduction of succinate accumulation by the inhibition of succinate dehydrogenase (SDH), malate/aspartate shuttle (MAS), or purine nucleotide cycle (PNC) served to reduce succinate, oxidative stress, and mito-SOX levels, thereby preventing oxidative stress-related neuronal damage and lessening seizure severity. Interestingly, simulating succinate accumulation with succinic acid dimethyl ester may induce succinate accumulation and increased oxidative stress and mito-SOX levels, as well as behavior and seizures in electroencephalograms similar to those observed in rats exposed to KA. Our results indicate that succinate accumulation may contribute to the increased oxidative stress/mitochondrial ROS levels, neuronal degeneration, and SE induced by KA administration. Furthermore, we found that succinate accumulation was mainly due to the inverse catalysis of SDH from fumarate, which was supplemented by the MAS and PNC pathways. These results reveal new insights into the mechanisms underlying SE and that reducing succinate accumulation may be a clinically useful therapeutic target in SE.

Risk of Parkinson disease in Sjögren syndrome administered ineffective immunosuppressant therapies: A nationwide population-based study.

To determine the incidence and risk of Parkinson disease (PD) in patients with Sjögren syndrome (SS) according to a nationwide population-based database.In total, 12,640 patients in the SS cohort and 50,560 in the non-SS cohort were enrolled from Taiwan's National Health Insurance Research Database from 2000 to 2010. We used the Cox multivariable proportional hazards model to determine the risk factors for PD in the SS cohort.We observed an increased incidence of PD in patients with SS, with a crude hazard ratio (HR) of 1.40 and an adjusted HR (aHR) of 1.23. The cumulative incidence of PD was 1.95% higher in the SS cohort than in the non-SS cohort. The SS cohort had an elevated HR under medication use, namely cevimeline and pilocarpine (crude HR, 1.28), hydroxychloroquine (crude HR, 1.43; aHR, 1.46), and methylprednisolone (crude HR, 2.21; aHR, 1.49). Patients receiving other non-hydroxychloroquine immunosuppressant therapies had a lower risk (aHR, 0.86) of PD. Furthermore, patients with SS aged 20 to 49 years had a 1.93-fold higher risk of PD than did those without SS (aHR, 1.93). The risk of PD was higher (aHR, 2.20) in patients with SS without comorbidities than in those with comorbidities. The aHR of PD significantly increased when the follow-up period exceeded 9 years (aHR, 1.93).We determined an increased risk of PD in patients with SS. Further investigation is warranted to determine the possible underlying mechanisms and the potential role of non-hydroxychloroquine immunosuppressants in ameliorating PD.

Pregabalin attenuates excitotoxicity in diabetes.

Diabetes can exacerbate seizures and worsen seizure-related brain damage. In the present study, we aimed to determine whether the standard antiepileptic drug pregabalin (PGB) protects against pilocarpine-induced seizures and excitotoxicity in diabetes. Adult male Sprague-Dawley rats were divided into either a streptozotocin (STZ)-induced diabetes group or a normal saline (NS) group. Both groups were further divided into subgroups that were treated intravenously with either PGB (15 mg/kg) or a vehicle; all groups were treated with subcutaneous pilocarpine (60 mg/kg) to induce seizures. To evaluate spontaneous recurrent seizures (SRS), PGB-pretreated rats were fed rat chow containing oral PGB (450 mg) for 28 consecutive days; vehicle-pretreated rats were fed regular chow. SRS frequency was monitored for 2 weeks from post-status epilepticus day 15. We evaluated both acute neuronal loss and chronic mossy fiber sprouting in the CA3 area. In addition, we performed patch clamp recordings to study evoked excitatory postsynaptic currents (eEPSCs) in hippocampal CA1 neurons for both vehicle-treated rats with SRS. Finally, we used an RNA interference knockdown method for Kir6.2 in a hippocampal cell line to evaluate PGB's effects in the presence of high-dose ATP. We found that compared to vehicle-treated rats, PGB-treated rats showed less severe acute seizure activity, reduced acute neuronal loss, and chronic mossy fiber sprouting. In the vehicle-treated STZ rats, eEPSC amplitude was significantly lower after PGB administration, but glibenclamide reversed this effect. The RNA interference study confirmed that PGB could counteract the ATP-sensitive potassium channel (KATP)-closing effect of high-dose ATP. By opening KATP, PGB protects against neuronal excitotoxicity, and is therefore a potential antiepileptogenic in diabetes. These findings might help develop a clinical algorithm for treating patients with epilepsy and comorbid metabolic disorders.

L-Theanine intake increases threshold for limbic seizures but decreases threshold for generalized seizures.

L-Theanine, an ethylamide derivate of glutamate found in abundance in green tea, has been shown to exert beneficial actions in animal models for several neurological disorders. We here investigated for the first time the effect of L-theanine intake on seizure susceptibility using acute pilocarpine and pentylenetetrazol (PTZ) mouse models for studying, respectively, limbic seizures or primarily generalized seizures. Moreover, we studied the effect of l-theanine intake on extracellular hippocampal and cortical glutamate and gamma-aminobutyric acid (GABA) levels, using in vivo microdialysis. Feeding mice with a 4% L-theanine solution significantly decreased their susceptibility to pilocarpine-induced seizures whereas susceptibility to PTZ-induced seizures was increased. The latter effect was linked to decreased extracellular GABA concentrations in frontal cortex.

[Detection of c-fos expression in animal brain in a pilocarpine model of temporal lobe epilepsy].

The dynamics of the involvement of different brain structures in a pathological process is very important for decoding the mechanisms of temporal lobe epilepsy. In this work, the experimental model of temporal lobe epilepsy induced by lithium chloride and pilocarpine was used. The method of immunochemical detection of the immediate early gene c-fos was used as an indicator of functioning neurons in the brain. The c-fos expression was determined at different time points (30, 60 and 90 min) after the pilocarpine injection. An increase in the c-fos expression was observed in neuronal populations during the development of the status epilepticus, the time and degree of involvement of different brain structures being different. The expression of c-fos was first observed in the piriform cortex, the olfactory tubercle, thalamic nuclei, lateral habenular nuclei, and the caudate putamen. Then the hippocampus, the septal formation, the amygdala, and basal ganglia were involved in the activation process. In the hypothalamic areas, c-fos expression was observed latest. These data contribute to understanding the mechanisms of temporal lobe epilepsy and searching for the ways of its therapy.

[Effects of Chinese herbal medicine Xifeng Capsule on multidrug resistance-associated protein 1 expression in hippocampus and cortex of rats with lithium-pilocarpine-induced epilepsy].

OBJECTIVE: To study the effects of Xifeng Capsule, a compound traditional Chinese herbal medicine, combined with carbamazepine on spontaneous epileptic seizure induced by lithium and pilocarpine in rats and the expression level of multidrug resistance-associated protein 1 (MRP1). METHODS: Lithium and pilocarpine were used to induce epilepsies in rats. All epileptic rats were randomly divided into model, high-dose Xifeng Capsule, medium-dose Xifeng Capsule, low-dose Xifeng Capsule, high-dose Xifeng Capsule plus carbamazepine (CBZ) (combined high-dose group), high-dose Xifeng Capsule plus half dose of CBZ (combined low-dose group) and CBZ groups with 10 rats in each group. And another 10 normal rats served as control. After treating 28 d, immunohistochemical method was used to detect the MRP1 expression in cortex and hippocampus of the epileptic rats. RESULTS: MRP1 expression in hippocampus of the treated groups was higher than that of the normal control group, with wider range and darker positive particles, but was lower than that of the model group. In the cortical areas, the differences between the combined high-dose group or the combined low-dose group and the model group were statistically significant (P<0.05). Regardless of the hippocampus CA1, CA3, gyrus or cortical areas, the influence of high-dose Xifeng Capsule on MRP1 distribution was superior to that of low-dose Xifeng Capsule; Xifeng Capsule combined with CBZ had better effects than low-dose Xifeng Capsule, medium-dose Xifeng Capsule and CBZ used alone (P<0.05). CONCLUSION: Xifeng Capsule used alone or combined with CBZ can effectively inhibit MRP1 expression in hippocampus and cortex of epileptic rats.

Pilocarpine used to treat xerostomia in patients submitted to radioactive iodine therapy: a pilot study.

UNLABELLED: Xerostomia complaint is very commonly associated to radioactive iodine therapy. Alternatives to treat this morbidity can offer better quality of life to patients with thyroid cancer submitted to adjuvant iodine therapy. AIM: to report on the experience with pilocarpine on the treatment of xerostomia in thyroid cancer patients submitted to adjuvant radioactive iodine therapy (RIT). MATERIALS AND METHODS: The five patients who met the inclusion criteria received 5mg of pilocarpine, 3 tid for one week. Side effects of the drug and subjective response to xerostomia complaints after treatment were evaluated. DESIGN: it is a prospective, non-randomized study. RESULTS: Sudoresis was the most frequent side effect of pilocarpine use, followed by fatigue and headache. Two patients reported relief of xerostomia using pilocarpine, but only one patient was able to tolerate the side effects. CONCLUSIONS: Pilocarpine seems to relieve xerostomia complaints in thyroid cancer patients because it is able to stimulate salivary flow, but the observed side effects made the patients refuse long-term therapy continuation.

Pilocarpina no tratamento de xerostomia em pacientes submetidos à iodoterapia: estudo piloto / Pilocarpine used to treat xerostomia in patients submitted to radioactive iodine therapy: a pilot study

Xerostomia é uma queixa tardia frequente associada à iodoterapia. Terapias para o tratamento desta morbidade podem proporcionar melhora na qualidade de vida dos pacientes com câncer de tireoide submetidos à iodoterapia adjuvante. OBJETIVOS: Relatar a experiência com o uso da pilocarpina no tratamento de xerostomia em pacientes com câncer de tireoide submetidos à iodoterapia adjuvante. MATERIAL E MÉTODOS: Cinco pacientes preencheram os critérios de inclusão e receberam 5mg de pilocarpina, 3 vezes ao dia, por uma semana. Os efeitos colaterais do medicamento e a resposta subjetiva à queixa de xerostomia após o tratamento foram avaliados. DESENHO DO ESTUDO: Trata-se de um estudo prospectivo, não-randomizado. RESULTADOS: Sudorese foi o efeito colateral mais comum com o uso da pilocarpina, seguido por cansaço e dor de cabeça. Dois pacientes relataram alívio da xerostomia com o uso da medicação, mas somente um paciente foi capaz de tolerar os efeitos colaterais. CONCLUSÕES: Pilocarpina parece aliviar os sintomas de xerostomia em pacientes submetidos à iodoterapia, já que o medicamento é capaz de estimular o fluxo salivar. No entanto, os efeitos colaterais observados inviabilizam seu uso por recusa por parte dos pacientes em continuar a terapia por períodos mais longos.

Xerostomia complaint is very commonly associated to radioactive iodine therapy. Alternatives to treat this morbidity can offer better quality of life to patients with thyroid cancer submitted to adjuvant iodine therapy. AIM: to report on the experience with pilocarpine on the treatment of xerostomia in thyroid cancer patients submitted to adjuvant radioactive iodine therapy (RIT). MATERIALS AND METHODS: The five patients who met the inclusion criteria received 5mg of pilocarpine, 3 tid for one week. Side effects of the drug and subjective response to xerostomia complaints after treatment were evaluated. DESIGN: it is a prospective, non-randomized study. RESULTS: Sudoresis was the most frequent side effect of pilocarpine use, followed by fatigue and headache. Two patients reported relief of xerostomia using pilocarpine, but only one patient was able to tolerate the side effects. CONCLUSIONS: Pilocarpine seems to relieve xerostomia complaints in thyroid cancer patients because it is able to stimulate salivary flow, but the observed side effects made the patients refuse long-term therapy continuation.

The morphology of conjunctiva after long-term topical anti-glaucoma treatment. A quantitative analysis.

On biopsy material, differences in the degree of conjunctival inflammation and fibrosis between topically treated glaucoma patients and age matched controls, were examined histologically. Eighteen patients with primary glaucoma underwent goniotrephinations, because maximal medical therapy had failed. The patients had received at least two types of topical anti-glaucoma drugs for at least 12 months (mean 46 months). The control group consisted of 18 age-matched control patients without glaucoma, who had received no topical therapy. These patients underwent cataract surgery or squint surgery. Biopsies were taken from the infero-temporal bulbar quadrant with a biopsy forceps. The specimens were fixed while stabilized on a rubber support to exclude any major shrinkage. Specimens were analyzed by light microscopy for the content of inflammatory cells (plasma cells, lymphocytes, polymorphs, macrophages and mast cells), goblet cells and fibroblasts. No significant difference in the histologic parameters between the two groups could be demonstrated. The study suggests that topical treatment for periods up to 4 years with anti-glaucoma drugs does not induce morphological signs of inflammation and fibrosis of the conjunctiva.