Publications by authors named "Bryan S Barker"

Benzodiazepines are the primary treatment option for organophosphate (OP)-induced status epilepticus (SE), but these antiseizure drugs (ASDs) lose efficacy as treatment is delayed. In the event of a mass civilian or military exposure, significant treatment delays are likely. New ASDs that combat benzodiazepine-resistant, OP-induced SE are critically needed, particularly if they can be efficacious after a long treatment delay.

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Organophosphorus (OP) compounds are deadly chemicals that exert their intoxicating effects through the irreversible inhibition of acetylcholinesterase (AChE). In addition to an excess of peripheral ailments, OP intoxication induces status epilepticus (SE) which if left untreated may lead to permanent brain damage or death. Benzodiazepines are typically the primary therapies for OP-induced SE, but these drugs lose efficacy as treatment time is delayed.

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SCN8A epileptic encephalopathy is a severe genetic epilepsy syndrome caused by de novo gain-of-function mutations of SCN8A encoding the voltage-gated sodium (Na) channel (VGSC) Na1.6. Therapeutic management is difficult in many patients, leading to uncontrolled seizures and risk of sudden unexpected death in epilepsy (SUDEP).

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Temporal lobe epilepsy (TLE) is a form of adult epilepsy involving the entorhinal cortex (EC). Layer II neurons of the medial EC (mEC) are spared and become hyperexcitable in TLE. Studies have suggested a role for T-type calcium channels (T-type Ca channels) in facilitating increases in neuronal activity associated with TLE within the hippocampus.

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De novo mutations of the sodium channel gene SCN8A result in an epileptic encephalopathy with refractory seizures, developmental delay, and elevated risk of sudden death. p.Arg1872Trp is a recurrent de novo SCN8A mutation reported in 14 unrelated individuals with epileptic encephalopathy that included seizure onset in the prenatal or infantile period and severe verbal and ambulatory comorbidities.

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The putative cache (Ca channel and chemotaxis receptor) domain containing 1 (CACHD1) protein has predicted structural similarities to members of the α2δ voltage-gated Ca channel auxiliary subunit family. CACHD1 mRNA and protein were highly expressed in the male mammalian CNS, in particular in the thalamus, hippocampus, and cerebellum, with a broadly similar tissue distribution to Ca3 subunits, in particular Ca3.1.

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Variants in the neuronal sodium channel gene SCN8A have been implicated in several neurological disorders. Early infantile epileptic encephalopathy type 13 results from de novo gain-of-function mutations that alter the biophysical properties of the channel. Complete loss-of-function variants of SCN8A have been identified in cases of isolated intellectual disability.

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Temporal lobe epilepsy (TLE) is a common form of adult epilepsy involving the limbic structures of the temporal lobe. Subiculum neurons act to provide a major output from the hippocampus and consist of a large population of endogenously bursting excitatory neurons. In TLE, subiculum neurons are largely spared, become hyperexcitable and show spontaneous epileptiform activity.

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Objective: To determine the functional effect of missense mutations in 2 children with intellectual disability and developmental delay but no seizures.

Methods: Genomic DNA was analyzed by next-generation sequencing. variants were introduced into the Na1.

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encephalopathy, or early infantile epileptic encephalopathy 13 (EIEE13), is caused predominantly by gain-of-function mutations in the voltage-gated Na channel Na1.6. Affected individuals suffer from refractory seizures, developmental delay, cognitive disability, and elevated risk of sudden unexpected death in epilepsy (SUDEP).

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Article Synopsis
  • SCN8A encephalopathy results from gain-of-function mutations in the Nav 1.6 sodium channel, causing early onset seizures, intellectual disability, and developmental delays in infants, with a significant percentage facing treatment-resistant seizures and potential sudden death.
  • High doses of phenytoin have shown effectiveness in some patients, prompting research into the mutation’s specific effects and its response to the drug.
  • Experimental results indicate that the SCN8A mutation I1327V enhances neuronal excitability and alters sodium channel dynamics, while phenytoin was found to improve activation and inactivation properties of the mutant channels, suggesting a potential treatment pathway.
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The medial prefrontal cortex (mPFC) is involved in a wide range of executive cognitive functions, including reward evaluation, decision-making, memory extinction, mood, and task switching. Manipulation of the mPFC has been shown to alter food intake and food reward valuation, but whether exclusive stimulation of mPFC pyramidal neurons (PN), which form the principle output of the mPFC, is sufficient to mediate food rewarded instrumental behavior is unknown. We sought to determine the behavioral consequences of manipulating mPFC output by exciting PN in mouse mPFC during performance of a panel of behavioral assays, focusing on food reward.

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Optogenetic and chemogenetic actuators are critical for deconstructing the neural correlates of behavior. However, these tools have several limitations, including invasive modes of stimulation or slow on/off kinetics. We have overcome these disadvantages by synthesizing a single-component, magnetically sensitive actuator, "Magneto," comprising the cation channel TRPV4 fused to the paramagnetic protein ferritin.

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Objective: The early infantile epileptic encephalopathy type 13 (EIEE13, OMIM #614558) results from de novo missense mutations of SCN8A encoding the voltage-gated sodium channel Nav1.6. More than 20% of patients have recurrent mutations in residues Arg1617 or Arg1872.

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