Epilepsy is the most common neurological disorder, with over 50 million people worldwide affected. Recent evidence suggests that the transient receptor potential cation channel subfamily V member 1 (TRPV1) may contribute to the onset and progression of some forms of epilepsy. Since the two nonpsychotropic cannabinoids cannabidivarin (CBDV) and cannabidiol (CBD) exert anticonvulsant activity in vivo and produce TRPV1-mediated intracellular calcium elevation in vitro, we evaluated the effects of these two compounds on TRPV1 channel activation and desensitization and in an in vitro model of epileptiform activity. Patch clamp analysis in transfected HEK293 cells demonstrated that CBD and CBDV dose-dependently activate and rapidly desensitize TRPV1, as well as TRP channels of subfamily V type 2 (TRPV2) and subfamily A type 1 (TRPA1). TRPV1 and TRPV2 transcripts were shown to be expressed in rat hippocampal tissue. When tested on epileptiform neuronal spike activity in hippocampal brain slices exposed to a Mg(2+)-free solution using multielectrode arrays (MEAs), CBDV reduced both epileptiform burst amplitude and duration. The prototypical TRPV1 agonist, capsaicin, produced similar, although not identical effects. Capsaicin, but not CBDV, effects on burst amplitude were reversed by IRTX, a selective TRPV1 antagonist. These data suggest that CBDV antiepileptiform effects in the Mg(2+)-free model are not uniquely mediated via activation of TRPV1. However, TRPV1 was strongly phosphorylated (and hence likely sensitized) in Mg(2+)-free solution-treated hippocampal tissue, and both capsaicin and CBDV caused TRPV1 dephosphorylation, consistent with TRPV1 desensitization. We propose that CBDV effects on TRP channels should be studied further in different in vitro and in vivo models of epilepsy.
Upholding WAG/Rij rats as a model of absence epileptogenesis: Hidden mechanisms and a new theory on seizure development.Neuroscience and Biobehavioral Reviews http://dx.doi.org/10. 1016/j.neubiorev.2016.09.017 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
AbstractThe WAG/Rij rat model has recently gathered attention as a suitable animal model of absence epileptogenesis. This latter term has a broad definition encompassing any possible cause that determines the development of spontaneous seizures; however, most of, if not all, preclinical knowledge on epileptogenesis is confined to the study of post-brain insult models such as traumatic brain injury or post-status epilepticus models. WAG/Rij rats, but also synapsin 2 knockout, Kv7 current-deficient mice represent the first examples of genetic models where an efficacious antiepileptogenic treatment (ethosuximide) was started before seizure onset. In this review, we have critically reconsidered all articles published regarding WAG/Rij rats, from the perspective that the period before SWD onset is considered as the latent period. In our new theory on seizure development, it is proposed that genes might be considered as the initial "insult" responsible for all plastic changes underpinning the development of spontaneous seizures. According to this idea, in WAG/Rij rats, genetic predisposition would lead to the development of abnormal bilateral cortical epileptic foci, which would then nongenetically stimulate the rest of the brain to rearrange networks in order to phenotypically develop seizures similarly to what happens during electrical kindling.
Age-related hearing loss (ARHL) and dementia are two highly prevalent conditions in the adult population. Recent studies have suggested that hearing loss is independently associated with poorer cognitive functioning. The aim of this study was to evaluate the prevalence of ARHL and cognitive impairment in a large sample of subjects older than 65 years and to correlate hearing function with cognitive function. A total of 488 subjects older than 65 years (mean age 72.8 years) participating in the Great Age Study underwent a complete audiological, neurological and neuropsychological evaluation as part of a multidisciplinary assessment. The prevalence of a hearing loss greater than 25 dB HL was 64.1%, of Central Auditory Processing Disorder (CAPD) was 14.3 and 25.3% of the subjects reported a hearing handicap as reported on the Hearing Handicap Inventory for the Elderly Screening Version questionnaire. Multiple logistic regression analysis corrected for gender, age and education duration showed that mild cognitive impairment (MCI) was significantly associated with hearing impairment (CAPD and hearing threshold; odds ratio 1.6, p = 0.05) and that Alzheimer's disease (AD) was significantly associated with CAPD (odds ratio 4.2, p = 0.05). Given that up to 80% of patients affected by MCI convert to AD, adding auditory tests to a screening cognitive battery might have value in the early diagnosis of cognitive decline.
SUMMARYObjective: Seizures may occur in close temporal association with a stroke or after a variable interval. Moreover, epilepsy is often encountered in patients with leukoaraiosis. Although early post-stroke seizures have been studied extensively, less attention has been paid to post-stroke epilepsy (PSE) and to epilepsy associated with leukoaraiosis (EAL). The aim of this paper is to review data concerning pathophysiology, prognosis, and treatment of PSE and EAL. Methods: We performed an extensive literature search to identify experimental and clinical articles on PSE and EAL. We also conducted a systematic review of risk factors for PSE and EAL among eligible studies. Results: PSE is caused by enhanced neuronal excitability within and near the scar. The role played by white matter changes in EAL remains to be elucidated. Meta-analysis showed that cortical involvement (odds ratio [OR]
High CSF NFL levels were found in patients with ALS, reflecting the burden of neurodegeneration. The significant relation between CSF NFL levels and disease progression suggests that NFL may be a useful marker of disease activity and progression in ALS.
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