Hypothesis: the classification of epileptic seizures according to systems of the CNS

Design, synthesis and computational evaluation of a novel intermediate salt of N-cyclohexyl-N-(cyclohexylcarbamoyl)-4-(trifluoromethyl) benzamide as potential potassium channel blocker in epileptic paroxysmal seizures

The narrow therapeutic range and limited pharmacokinetics of available Antiepileptic drugs (AEDs) have raised serious concerns in the proper management of epilepsy. To overcome this, the present study attempts to identify a candidate molecule targeting voltage gated potassium channels anticipated to have superior pharmacological than existing potassium channel blockers. The compound was synthesized by reacting (S)-(+)-2,3-dihydro-1H-pyrrolo[2,1-c][1,4] benzodiazepine5,11(10H,11aH)-dione with 4-(Trifluoromethyl) benzoic acid (C₈H₅F₃O₂) in DMF and N,N'-dicyclohexylcarbodiimide (DCC) which lead to the formation of an intermediate salt of N-cyclohexyl-N-(cyclohexylcarbamoyl)-4-(trifluoromethyl)benzamide with a perfect crystalline structure. The structure of the compound was characterized by FTIR, ¹H NMR and ¹³C NMR analysis. The crystal structure is confirmed by single crystal X-ray diffraction analysis. The Structure-Activity Relationship (SAR) studies revealed that substituent of fluoro or trifluoromethyl moiety into the compound had a great effect on the biological activity in comparison to clinically used drugs. Employing computational approaches the compound was further tested for its affinity against potassium protein structure by molecular docking in addition, bioactivity and ADMET properties were predicted through computer aided programs.

An In Vitro Study of New Antiepileptic Drugs and Astrocytes

PURPOSE

The aim of our research was to study some biochemical modifications elicited in primary rat astrocyte cultures by treatment with gabapentin (GBP), carbamazepine (CBZ), lamotrigine (LTG), topiramate (TPM), oxcarbazepine (OXC), tiagabine (TGB), and levetiracetam (LEV), commonly used in the treatment of epilepsy. We investigated the biologic effects of these anticonvulsants (AEDs) at concentrations of 1, 10, 50, and 100 microg/ml.

METHODS

The study was performed by examining cell viability (MTT assay), cell toxicity [lactate dehydrogenase (LDH) release in the medium], glutamine synthetase (GS) activity, reactive oxygen species (ROS) production, lipoperoxidation level (malondialdehyde; MDA), and DNA fragmentation (COMET assay). The level of the expression of 70-kDa heat-shock protein (HSP70) and inducible nitric oxide synthase (iNOS) as oxidative stress-modulated genes also was determined.

RESULTS

Our experiments indicate that CBZ, TPM, and OXC induce stress on astrocytes at all concentrations. GBP, LTG, TGB, and LEV, at low concentrations, do not significantly change the metabolic activities examined and do not demonstrate toxic actions on astrocytes. They do so at higher concentrations.

CONCLUSIONS

Most AEDs have effects on glial cells and, when used at an appropriate cell-specific concentrations, may be well tolerated by cortical astrocytes. However, at higher concentrations, GBP, LTG, TGB, and LEV seem to be better tolerated than are CBZ, TPM, and OXC. These findings may reveal novel ways of producing large numbers of new AEDs capable of reducing the extent of inflammation, neuronal damage, and death under pathological conditions such as epilepsy and/or traumatic brain injury.

Modern electroencephalography: its role in epilepsy management

Epilepsy is the area in which electroencephalography is probably of greatest potential clinical value, and yet is most abused. In general, the sensitivity of the waking interictal EEG for detecting epilepsy and its specificity for distinguishing epilepsy from other episodic disorders are both very limited, and routine examination for diagnostic screening or follow up is of little value. However, as this review attempts to demonstrate, EEG is of crucial importance for answering specific, clearly defined questions which commonly arise in the management of seizure disorders, especially so, when non-routine and if necessary complex investigations are undertaken, to address the problems of individual patients.

Detection and evolution of rhytmic components in ictal EEG using short segment spectra and discriminant analysis

An automated method for analysis of ictal EEG is described which aims to reliably detect one or several rhythmic components in short EEG segments (2 sec) and to display their presence, frequency, amplitude, location, and temporal evolution. Spectra were estimated and compared using fast Fourier transform (FFT) and autoregressive modelling (AR). A subsequent linear discriminant analysis decided whether a spectral peak is likely to be caused by rhythmic activity or by the inherent statistical variability. FFT was found to perform better than AR in the detection of rhythmic components, yielding a false-positive rate of 0.825%, a false-negative rate of 2% (signal to noise ratio -4.6 dB), a frequency resolution of 2 Hz, and a temporal resolution of 0.5 sec. Seizure analysis revealed that the ictal scalp EEG of even short seizures can show a complex evolution of rhythmic patterns which are impossible or difficult to recognize by visual inspection or conventional spectral analysis. The following phenomena are demonstrated: superposition of two rhythmic components suggesting two cerebral regions discharging simultaneously and independently with their own pacemakers, sudden and gradual change of frequencies, and gradual development of harmonic frequencies. It is suggested that a more precise correlation between rhythmic generators and seizure symptomatology might allow more predictable pharmacological responses in antiepileptic therapy.

Mapping of spontaneous spike and wave discharges in Wistar rats with genetic generalized non-convulsive epilepsy

Electrical activity was recorded in different parts of the brain in Wistar rats from a strain with genetic generalized non-convulsive epilepsy (GNCE or absence epilepsy). Movable bipolar electrodes were lowered stereotaxically by 1 mm steps into the brain in immobilized animals. Spontaneous spike and wave discharges (SWD) of the largest amplitude were recorded in the cortex and in lateral nuclei of the thalamus where they appeared occasionally to precede. Smaller amplitude SWD were recorded in the striatum, hypothalamus, tegmentum and substantia nigra. No SWD were recorded in limbic structures. Partial limbic seizures induced by the introduction of the electrode did not interfere with occurrence of cortical SWD. These results confirm the primacy of thalamocortical involvement in SWD of GNCE. The absence of spread to limbic structures and the implication of a precisely limited substrate in GNCE accounts for the clinical and pharmacological specificity of this particular kind of epilepsy.