The anti-epileptic drug lacosamide (Vimpat) has anxiolytic property in rodents

An aqueous extract of Khaya senegalensis (Desv.) A. Juss. (Meliaceae) prevents seizures and reduces anxiety in kainate-treated rats: modulation of GABA neurotransmission, oxidative stress, and neuronal loss in the hippocampus

Ethnopharmacological relevance

Temporal lobe epilepsy is the most common form of drug-resistant epilepsy. Therefore, medicinal plants provide an alternative source for the discovery of new antiepileptic drugs.

Aim of the study

This study was aimed at investigating the antiepileptic- and anxiolytic-like effects of an aqueous extract of Khaya senegalensis (K. senegalensis) in kainate-treated rats.

Methods

Seventy-two rats received a single dose of kainate (12 mg/kg) intraperitoneally. Those that exhibited two hours of status epilepticus were selected and monitored for the first spontaneous seizure. Then, animals that developed seizures were divided into 6 groups of 8 rats each and treated twice daily for 14 days as follows: negative control group received per os (p.o.) distilled water (10 ml/kg); two positive control groups received either sodium valproate (300 mg/kg, p.o.) or phenobarbital (20 mg/kg, p.o.); and three test groups received different doses of the extract (50, 100, and 200 mg/kg, p.o.). In addition, a group of 8 normal rats (normal control group) received distilled water (10 ml/kg, p.o.). During the treatment period, the animals were video-monitored 12 h/day for behavioral seizures. At the end of the treatment period, animals were subjected to elevated plus-maze and open field tests. Thereafter, rats were euthanized for the analysis of γ-aminobutyric acid (GABA) concentration, oxidative stress status, and neuronal loss in the hippocampus.

Results

The aqueous extract of K. senegalensis significantly reduced spontaneous recurrent seizures (generalized tonic-clonic seizures) and anxiety-like behavior compared to the negative control group. These effects were more marked than those of sodium valproate or phenobarbital. Furthermore, the extract significantly increased GABA concentration, alleviated oxidative stress, and mitigated neuronal loss in the dentate gyrus of the hippocampus.

Conclusion

These findings suggest that the aqueous extract of K. senegalensis possesses antiepileptic- and anxiolytic-like effects. These effects were greater than those of sodium valproate or phenobarbital, standard antiepileptic drugs. Furthermore, these effects are accompanied by neuromodulatory and antioxidant activities that may be related to their behavioral effects. These data justify further studies to identify the bioactive molecules present in the extract for possible future therapeutic development and to unravel their mechanisms of action.

Effects of Lacosamide Treatment on Epileptogenesis, Neuronal Damage and Behavioral Comorbidities in a Rat Model of Temporal Lobe Epilepsy

Clinically, temporal lobe epilepsy (TLE) is the most prevalent type of partial epilepsy and often accompanied by various comorbidities. The present study aimed to evaluate the effects of chronic treatment with the antiepileptic drug (AED) lacosamide (LCM) on spontaneous motor seizures (SMS), behavioral comorbidities, oxidative stress, neuroinflammation, and neuronal damage in a model of TLE. Vehicle/LCM treatment (30 mg/kg, p.o.) was administered 3 h after the pilocarpine-induced status epilepticus (SE) and continued for up to 12 weeks in Wistar rats. Our study showed that LCM attenuated the number of SMS and corrected comorbid to epilepsy impaired motor activity, anxiety, memory, and alleviated depressive-like responses measured in the elevated plus maze, object recognition test, radial arm maze test, and sucrose preference test, respectively. This AED suppressed oxidative stress through increased superoxide dismutase activity and glutathione levels, and alleviated catalase activity and lipid peroxidation in the hippocampus. Lacosamide treatment after SE mitigated the increased levels of IL-1β and TNF-α in the hippocampus and exerted strong neuroprotection both in the dorsal and ventral hippocampus, basolateral amygdala, and partially in the piriform cortex. Our results suggest that the antioxidant, anti-inflammatory, and neuroprotective activity of LCM is an important prerequisite for its anticonvulsant and beneficial effects on SE-induced behavioral comorbidities.

Lacosamide improves biochemical, genotoxic, and mitochondrial parameters after PTZ-kindling model in mice

This study evaluated the effect of lacosamide (LCM) on biochemical and mitochondrial parameters after PTZ kindling in mice. Male mice were treated on alternative days for a period of 11 days with LCM (20, 30, or 40 mg/kg), saline, or diazepam (2 mg/kg), before PTZ administration (50 mg/kg). The hippocampi were collected to evaluate free radicals, the activities of superoxide dismutase (SOD), catalase (CAT), and the mitochondrial complexes I-III, II, and II-III, as well as Bcl-2 and cyclo-oxygenase-2 (COX-2) expressions. Hippocampi, blood, and bone marrow were collected for genotoxic and mutagenic evaluations. LCM 40 mg/kg increased latency and decreased percentage of seizures, only on the 3rd day of observation. The dose of 30 mg/kg only showed positive effects on the percentage of seizures on the 2nd day of observation. LCM decreased free radicals and SOD activity and the dose of 40 mg/kg were able to increase CAT activity. LCM 30 and 40 mg/kg improved the enzymatic mitochondrial activity of the complex I-III and LCM 30 mg/kg improved the activity of the complex II. In the comet assay, the damage induced by PTZ administration was reduced by LCM 20 and 30 mg/kg. The dose of 20 mg/kg increased COX-2 expression while the highest dose used, 40 mg/kg, was able to reduce this expression when compared to the group treated with LCM 20 mg/kg. Although LCM did not produce the antiepileptogenic effect in vivo, it showed the neuroprotective effect against oxidative stress, bioenergetic dysfunction, and DNA damage induced by the repeated PTZ administration.

Similarities and dissimilarities in the effects of benzodiazepines and specific serotonin reuptake inhibitors (SSRIs) in the defensive marble burying test: A systematic review and meta-analysis

One problem areas of animal models and tests for neuropsychiatric disorders is unclear reproducibility, including both internal and external validity. One way to examine external validity is with systematic reviews and meta-analyses, a standard practice in clinical research that is relatively neglected in preclinical research. Considering the need to evaluate the validity and reproducibility of frequently used animal models, this study presents a meta-analysis of the effects of prototypic benzodiazepines and specific serotonin reuptake inhibitors (SSRIs) in the mouse defensive marble burying test (MBT). These drug groups were selected because although they differ in their biological targets as well as in their clinical use, they are both commonly used for the treatment of anxiety disorders. A PubMed literature search was performed to identify studies that examined the effects of benzodiazepines (diazepam, alprazolam, chlordiazepoxide, clonazepam) or SSRIs (fluoxetine, citalopram, escitalopram, fluvoxamine, paroxetine) in the MBT in mice. For benzodiazepines, 73 experiments were included. Benzodiazepines effect size was 2.04 and Q statistics was 1959 with a significant correlation between dose and effect size (r = 0.31, p = 0.007). For SSRIs we identified 47 experiments. Effect size of SSRIs was 2.24 and Q statistics was 493.38. No correlation was found between dose and effect size (r = 0.23, p = 0.12). The current results support the external validity of the defensive marble burying test as a screening test for anxiolytic effects. However, these results indicate that significant attention should be given to the administration schedules of benzodiazepines and SSRIs.

The Impact of Prophylactic Lacosamide on LPS-Induced Neuroinflammation in Aged Rats

Sepsis-induced central nervous system damage is called sepsis-associated encephalopathy (SAE). In addition to neuroinflammation, oxidative stress and apoptosis act in the development of SAE. In the current study, we evaluated the protective effects of lacosamide (LCM) on neuroinflammation induced by lipopolysaccharide (LPS). Twenty-four Wistar albino rats were divided into 3 groups as controls, LPS group (5 mg/kg i.p.), and LPS plus LCM group (5 mg/kg i.p and 40 mg/kg i.p, respectively). In the rat brain, LPS-induced tissue damage was revealed histopathologically as hyperemia and microhemorrhages. LCM pretreatment ameliorated these histopathological changes. LPS decreased brain TAS levels and significantly increased MDA, CRP, HSP, IL-1β, and TNF-α expressions in the cortex, hippocampus, and cerebellum. Western analysis revealed increased brain tissue levels of TNF-α, NF-Kβ, and caspase-3 following LPS. Prophylactic LCM treatment reversed these parameters including oxidative stress, inflammation, and apoptosis in the cortex, hippocampus, and cerebellum.

Effect of lacosamide on ethanol induced conditioned place preference and withdrawal associated behavior in mice: Possible contribution of hippocampal CRMP-2

BACKGROUND

Excessive consumption of ethanol is known to activate the mTORC1 pathway and to enhance the Collapsin Response Mediator Protein-2 (CRMP-2) levels in the limbic region of brain. The latter helps in forming microtubule assembly that is linked to drug taking or addiction-like behavior in rodents. Therefore, in this study, we investigated the effect of lacosamide, an antiepileptic drug and a known CRMP-2 inhibitor, which binds to CRMP-2 and inhibits the formation of microtubule assembly, on ethanol-induced conditioned place preference (CPP) in mice.

METHODS

The behavior of mice following ethanol addiction and withdrawal was assessed by performing different behavioral paradigms. Mice underwent ethanol-induced CPP training with alternate dose of ethanol (2 g/kg, po) and saline (10 ml/kg, po). The effect of lacosamide on the expression of ethanol-induced CPP and on ethanol withdrawal associated anxiety and depression-like behavior was evaluated. The effect of drug on locomotor activity was also assessed and hippocampal CRMP-2 levels were measured.

RESULTS

Ethanol-induced CPP was associated with enhanced CRMP-2 levels in the hippocampus. Lacosamide significantly reduced the expression of ethanol-induced CPP and alleviated the levels of hippocampal CRMP-2 but aggravated withdrawal-associated anxiety and depression in mice.

CONCLUSION

The present study demonstrated the beneficial effect of lacosamide in attenuation of expression of ethanol induced conditioned place preference via reduction of hippocampal CRMP-2 level. These findings suggest that lacosamide may be investigated further for ethanol addiction but not for managing withdrawal.

Lacosamide-induced excessive laughing in a patient with Lennox-Gastaut syndrome

Lacosamide is one of the third-generation antiseizure drugs that block voltage-gated sodium channels by enhancing slow inactivation. The most common adverse effects of lacosamide include dizziness, headache, nausea, vomiting, diplopia, fatigue, and sedation. Less common side effects include memory impairment, weight gain, rash, and atrioventricular block. In this article, we describe a patient with Lennox–Gastaut syndrome who developed excessive laughing as a rare side effect of lacosamide with complete resolution after discontinuation of the medication. The present case illustrates that excessive laughing may occur as an adverse effect of lacosamide.

Effect of lacosamide on depression and anxiety symptoms in patients with focal refractory epilepsy: A prospective multicenter study

INTRODUCTION

Depression is the main psychiatric comorbidity in epilepsy with an estimated prevalence between 20% and 55% and one of the main determinants of quality of life. The aim of this study was to investigate the effect of lacosamide (LCM) on mood and anxiety symptoms in patients with focal onset seizures (FOS). The secondary objective was to evaluate if the potential modifications in variables were related to seizure control or to the intrinsic effect of LCM.

MATERIAL AND METHODS

We performed a prospective multicenter study in 8 tertiary epilepsy centers in adults with FOS in which LCM was initiated as add-on therapy. Patients' mood and quality of life were evaluated through questionnaires and scales such as the Beck Depression Inventory-II (BDI-II), the State-Trait Anxiety Inventory (STAI-S/T), the Hospital Anxiety and Depression Scale (HADS), and the Quality of Life in Epilepsy-10 (QOLIE-10). Initiation of psychotropic medication was not allowed during the observation period. Patients with diagnosis of major depression or bipolar disorder were excluded. Evaluations were scheduled before LCM treatment, at 3 and 6months.

RESULTS

Forty-nine patients were included (51% female) with an average age of 39.5years (range 18-65). At the start of treatment with LCM, 65.3% of the patients were on treatment with one antiepileptic drug (AED). Based on BDI-II, 38.8% of patients had depressive symptoms and 46.9% according to HADS Depression (HADS-D), 63.3% of patients presented pathological levels of anxiety (STAI-S/T), and 44.9% according to HADS Anxiety (HADS-A). Quality of Life in Epilepsy-10 showed that 57.1% of patients had a relevant reduction in their quality of life. After LCM, the score on the BDI-II depression scale decreased significantly (p<0.001). Based on the STAI and HADS-anxiety scales, patients who had a pathological anxiety at baseline, significantly improved. The QOLIE-10 improved significantly over the observation period (p<0.001). At 6months, 28.3% of patients were seizure-free (67.4% were responders). The improvements on depression and anxiety scores were not statistically related to seizure control.

CONCLUSION

Lacosamide seems to have a positive effect on depressive and anxiety symptoms. Although the efficacy of LCM in seizure control was demonstrated, the antidepressant and anxiolytic effect on mood and anxiety seems to be an independent factor.

mTORC1-dependent translation of collapsin response mediator protein-2 drives neuroadaptations underlying excessive alcohol-drinking behaviors

Mammalian target of rapamycin complex 1 (mTORC1) has an essential role in dendritic mRNA translation and participates in mechanisms underlying alcohol-drinking and reconsolidation of alcohol-related memories. Here, we report that excessive alcohol consumption increases the translation of downstream targets of mTORC1, including collapsin response mediator protein-2 (CRMP-2), in the nucleus accumbens (NAc) of rodents. We show that alcohol-mediated induction of CRMP-2 translation is mTORC1-dependent, leading to increased CRMP-2 protein levels. Furthermore, we demonstrate that alcohol intake also blocks glycogen synthase kinase-3β (GSK-3β)-phosphorylation of CRMP-2, which results in elevated binding of CRMP-2 to microtubules and a concomitant increase in microtubule content. Finally, we show that systemic administration of the CRMP-2 inhibitor lacosamide, or knockdown of CRMP-2 in the NAc decreases excessive alcohol intake. These results suggest that CRMP-2 in the NAc is a convergent point that receives inputs from two signaling pathways, mTORC1 and GSK-3β, that in turn drives excessive alcohol-drinking behaviors.

LAM study: Effects of lacosamide on behaviour and quality of life in patients with epilepsy

INTRODUCTION

Psychiatric comorbidities are common in epileptic patients, and evaluating the impact of antiepileptic drugs on patients' moods is therefore essential. The aim of this study is to assess the effects of lacosamide on behaviour and quality of life in people with epilepsy.

METHODS

We conducted a multicentre prospective observational study of poorly-controlled epileptic patients who received lacosamide as an adjuvant treatment. Patients were evaluated on 4 occasions during a 12-month period. The impact of lacosamide on patients' mood and quality of life was assessed with the Quality of Life in Epilepsy Inventory-10 (QOLIE-10), the Hospital Anxiety and Depression Scale (HADS), and the Barratt Impulsiveness Scale (BIS-11). As a secondary objective, we evaluated the effectiveness and safety of lacosamide.

RESULTS

We included 55 patients with a mean age of 47.1±18.4 years. At baseline, 34.5% of the patients had psychiatric comorbidities; the mean number of crises in the previous month was 3.6±4.3. The QOLIE-10 and HADS scales revealed statistically significant improvements in patients with a poor baseline condition (anxiety, depression, and/or poor quality of life). The BIS-11 scale detected no impulsive behaviour during follow-up. After 12 months of treatment, 51.9% of the patients were seizure-free and 77.8% experienced a reduction of at least 50% in seizure frequency. Adverse effects were mild in most cases; lacosamide was discontinued in 10 patients (18.2%).

CONCLUSIONS

Lacosamide is a safe and effective treatment option for patients with epilepsy and psychiatric comorbidities.

Antiepileptic drugs in the treatment of psychiatric disorders

The clinical interface between psychiatry and neurology is epilepsy; the pharmacological expression of this interface is antiepileptic drugs (AEDs), as they are used to treat both epilepsy and psychiatric disorders, especially bipolar disorders. The prevalence of psychiatric comorbidity and the risk of suicidal behavior/ideation/suicide are markedly increased in patients with epilepsy (PWE). Though AEDs receive initial indications for the treatment of epilepsy, currently the majority of AEDs are used to treat pain and psychiatric disorders. Thus in selecting the appropriate AEDs for treatment of PWE, consideration should be given to which AEDs best treat the epileptic disorder and the psychiatric comorbidity. This review is an overview of 21 AEDs in which negative psychotropic properties, approved indications in psychiatry, off-label studied uses in psychiatry, and principal uses in psychiatry are presented with literature review. A total of 40 psychiatric uses have been identified. Of the 21 AEDs reviewed, only 5 have U.S. Food and Drug Administration and/or European Medicines Agency psychiatric approval for limited uses; the majority of AEDs are used off-label. Many of these off-label uses are based on case reports, open-label studies, and poorly controlled or small-sample-size studies. In some instances, off-label use persists in the face of negative pivotal trials. Further placebo-controlled (augmentation and monotherapy) parallel-arm research with active comparators is required in the complex field of AED treatment of psychiatric disorders to minimize the treatment gap not only for PWE with psychiatric disorders, but also for psychiatric patients who would benefit from properly studied AEDs while minimizing adverse effects.

Collapsin response mediator protein-2: an emerging pathologic feature and therapeutic target for neurodisease indications

Collapsin response mediator protein-2 (DPYSL2 or CRMP2) is a multifunctional adaptor protein within the central nervous system. In the developing brain or cell cultures, CRMP2 performs structural and regulatory functions related to cytoskeletal dynamics, vesicle trafficking and synaptic physiology whereas CRMP2 functions in adult brain are still being elucidated. CRMP2 has been associated with several neuropathologic or psychiatric conditions including Alzheimer's disease (AD) and schizophrenia, either at the level of genetic polymorphisms; protein expression; post-translational modifications; or protein/protein interactions. In AD, CRMP2 is phosphorylated by glycogen synthase kinase-3β (GSK3β) and cyclin dependent protein kinase-5 (CDK5), the same kinases that act on tau protein in generating neurofibrillary tangles (NFTs). Phosphorylated CRMP2 collects in NFTs in association with the synaptic structure-regulating SRA1/WAVE1 (specifically Rac1-associated protein-1/WASP family verprolin-homologous protein-1) complex. This phenomenon could plausibly contribute to deficits in neural and synaptic structure that have been well documented in AD. This review discusses the essential biology of CRMP2 in the context of nascent data implicating CRMP2 perturbations as either a correlate of, or plausible contributor to, diverse neuropathologies. A discussion is made of recent findings that the atypical antidepressant tianeptine increases CRMP2 expression, whereas other, neuroactive small molecules including the epilepsy drug lacosamide and the natural brain metabolite lanthionine ketimine appear to bind CRMP2 directly with concomitant affects on neural structure. These findings constitute proofs-of-concept that pharmacological manipulation of CRMP2 is possible and hence, may offer new opportunities for therapy development against certain neurological diseases.

Comparative study of five antiepileptic drugs on a translational cognitive measure in the rat: relationship to antiepileptic property

RATIONALE

Antiepileptic drugs (AEDs) have been available for many years; yet, new members of this class continue to be identified and developed due to the limitations of existing drugs, which include a propensity for cognitive impairment. However, there is little preclinical information about the cognitive effects they produce, which clinically include deficits in attention and slowing of reaction time.

OBJECTIVES

The purpose of this study was to profile two first-generation AEDs, phenytoin and valproate, and three second-generation AEDs, levetiracetam, pregabalin and lacosamide. Initially, each drug was examined across a range of well characterised preclinical seizure tests, and then each drug was evaluated in the five-choice serial reaction time test (5-CSRTT) based on efficacious doses from the seizure tests.

MATERIALS AND METHODS

Each AED was tested for anti-seizure efficacy in either (1) the maximal electroshock seizure test, (2) s.c. PTZ seizure test, (3) amygdala-kindled seizures and (4) the genetic absence epilepsy rat of Strasbourg model of absence seizures. On completion of these studies, each drug was tested in rats trained to asymptotic performance in the 5-CSRTT (0.5 s SD, 5 s ITI, 100 trials). Male rats were used in all studies.

RESULTS

Each AED was active in at least one of the seizure tests, although only valproate was active in each test. In the 5-CSRT test, all drugs with the exception of levetiracetam, significantly slowed reaction time and increased omissions. Variable effects were seen on accuracy. The effect on omissions was reversed by increasing stimulus duration from 0.5 to 5 s, supporting a drug-induced attention deficit. Levetiracetam had no negative effect on performance; indeed, reaction time was slightly increased (i.e. faster).

CONCLUSIONS

These results highlight somewhat similar effects of phenytoin, valproate, pregabalin and lacosamide on attention and reaction time, and comparison to efficacious doses from the seizure tests support the view that there may be a better separation with the newer AEDs. Levetiracetam had no detrimental effect in the 5-CSRTT, which may be consistent with clinical experience where the drug is considered to be well tolerated amongst the AED class.