Safranal carried by nanostructured lipid vehicles inhibits generalized epilepsy in mice.

Safranal, a main component of Crocus sativus, is suggested to have neuroprotective effects. The aim of this study was to investigate the effect of safranal and nanostructured lipid vehicle (NLV) carried safranal in acute and chronic experimental mice models of epilepsy. In PILO acute seizure model, safranal dose-dependently extended latency to generalized seizure, decreased the highest seizure stages and the number of generalized seizures. Moreover, NLV carried safranal further enhanced the anti-seizure effect, which is comparable to the action of sodium valproate. Meanwhile, NLV carried safranal reduced and delayed the electroencephalogram spectra power after pilocarpine injection. In histological aspect, safranal dose-dependently reduced the loss of neurons induced by seizure and NLV system further improved this protection at the same dose. In MES acute model, safranal markedly increased the electroconvulsive threshold, where NLV further improved its effect. In PTZ chronic seizure model, NLV carried safranal significantly delayed the kindling rate of progress and the time it took to reach generalized seizures as compared to NLV control group. In conclusion, this study indicates that safranal inhibits generalized seizure in acute and chronic epilepsy models in mice and NLV can enhance this effect. So, NLV carried safranal may have potential value in treatment of generalized epilepsy.

1-Triacontanol cerotate; isolated from Marsilea quadrifolia Linn. ameliorates reactive oxidative damage in the frontal cortex and hippocampus of chronic epileptic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Marsilea quadrifolia Linn. (MQ) has been used for insomnia and epileptic disorders in traditional Indian medicine. The present study is to isolate the active component responsible for antiepileptic property of MQ by evaluating its ability to minimize the reactive oxidative damage in brain due to chronic epilepsy in rat. MATERIALS AND METHODS: 1-Triacontanol cerotate (1TAC) was isolated after chromatography on a silica gel from dried petroleum ether fraction of methanolic extract of MQ. Acute oral toxicity studies of 1TAC were carried out and efficacy of 1TAC on malondialdehyde (MDA) and reduced glutathione (GSH) production in different brain areas of chronic pentylenetetrazole (PTZ) induced epileptic rats were evaluated. RESULTS: Our results showed that PTZ-kindled chronic epileptic rats had an increase MDA and decreased GSH concentration in the frontal cortex as well as hippocampus, compared to the normal control. MDA and GSH concentrations in those brain areas were normalized after treatment with sodium valproate (SV) in 200 mg kg(-1)bw; as well as 1TAC in 40 and 80 mg kg(-1)bw doses. CONCLUSION: Production of reactive oxygen species (ROS) is known to worsen epileptogenesis. The isolated component 1TAC which reduced the reactive oxidative damage in hippocampus and frontal cortex of PTZ kindled rats could be responsible for antiepileptic property of MQ. Its action is found to be dose dependent, with 80 mg kg(-1)bw showing even better efficacy than 200 mg kg(-1)bw of SV.

Anatomically dependent anticonvulsant properties of temporally-coded electrical stimulation.

In the PTZ animal model of epilepsy, electrical stimulation applied to the amygdaloid complex may result in either pro-convulsive or anticonvulsant effect, depending on the temporal pattern used (i.e. periodic-PS and non-periodic-NPS electrical stimulation). Our hypothesis is that the anatomical target is a determinant factor for the differential effect of temporally-coded patterns on seizure outcome. The threshold dose of PTZ to elicit forelimb clonus and generalized tonic-clonic seizure behavior was measured. The effect of amygdaloid complex PS on forelimb clonus threshold showed a pro-convulsive effect while NPS was anticonvulsant. NPS also significantly increased generalized tonic-clonic threshold; while PS, although at lower threshold levels, did not present statistical significance. Thalamus stimulation did not affect forelimb clonus threshold and showed similar anticonvulsant profiles for both PS and NPS on generalized tonic-clonic threshold. In summary, the anatomical target is a determinant factor on whether temporally-coded ES differentially modulates seizure outcome.

vGLUT2 heterozygous mice show more susceptibility to clonic seizures induced by pentylenetetrazol.

Glutamate, the most abundant excitatory neurotransmitter in the central nervous system, is well known to be implicated in epileptic seizures. Therefore, impairments in glutamate transport could have an involvement in the mechanism of epileptogenesis. The uptake of glutamate into synaptic vesicles is mediated by vesicular glutamate transporters (vGLUTs). There are three known vGLUT isoforms, vGLUT1-3. In this study, we are particularly interested in the vGLUT2 isoform. We investigated the possible role of vGLUT2 in pentylenetetrazol (PTZ)-induced seizure generation. Seizure threshold of PTZ was compared in vGLUT2 heterozygous knock out (HET) and wild type (WT) mice. In comparison with their WT littermates a lower dose of PTZ was needed in the vGLUT2 HET mice until the onset of the first myoclonic jerk. The threshold for PTZ-induced clonic seizure activity was also lower in the vGLUT2 HET mice. These results indicate, for the first time, that vGLUT2 is likely involved in the epileptogenesis of generalized seizures.

Anticonvulsant activity of Nylandtia spinosa L. Dumont (Polygalaceae) aqueous and methanol leaf extracts in mice.

Aqueous and methanol leaf extracts of Nylandtia spinosa L. Dumont (Polygalaceae) were evaluated for anticonvulsant activity against tonic seizures produced in mice by pentylenetetrazole (PTZ), bicuculline, picrotoxin, and N-methyl-DL-aspartic acid (NMDLA). Aqueous leaf extract of N. spinosa (50-400 mg/kg, i.p.) and methanol extract (50-400 mg/kg, i.p.) significantly attenuated PTZ (95 mg/kg, i.p.)-induced tonic seizures. Doses of 400 mg/kg (i.p.) and 100-400 mg/kg (i.p.) of aqueous extract of N. spinosa significantly delayed the onset of tonic seizures elicited by bicuculline (35 mg/kg, i.p.) and picrotoxin (12 mg/kg, i.p.), respectively. Methanol extract (200-400 mg/kg, i.p.) and (50-400 mg/kg, i.p.) significantly delayed the onset of tonic seizures induced by bicuculline (35 mg/kg, i.p.) and picrotoxin (12 mg/kg, i.p.), respectively, whereas 400 mg/kg (i.p.) significantly reduced the incidence of picrotoxin (12 mg/kg, i.p.)-induced seizures. Both aqueous and methanol leaf extracts of N. spinosa did not affect NMDLA (400 mg/kg, i.p.)-induced tonic seizures. Phenobarbitone (12.5 mg/kg, i.p.) and diazepam (0.5 mg/kg, i.p.) antagonized tonic seizures induced by PTZ (95 mg/kg, i.p.), bicuculline (35 mg/kg, i.p.), and picrotoxin (12 mg/kg, i.p.) but did not affect NMDLA (400 mg/kg, i.p.)-induced seizures. Phenytoin (30 mg/kg, i.p.) did not alter the tonic seizures produced by either PTZ (95 mg/kg, i.p.), bicuculline -2-(35 mg/kg, i.p.), or picrotoxin (12 mg/kg, i.p.). The results obtained indicate that both aqueous and methanol leaf extracts of N. spinosa possess anticonvulsant property, thus justifying the use of the plant by traditional medicine practitioners in the treatment of epilepsy. The relatively high LD(50) of greater than 3600 mg/kg (p.o.) and 1780 mg/kg (i.p.) obtained with the aqueous extract suggest that the plant is relatively safe in mice. The phytochemical analysis carried out showed the presence of tannins, saponins, reducing sugars, alkaloids, flavonoids, triterpene steroids, and cardiac glycosides in the plant material.

Severe reversible toxic encephalopathy induced by cisplatin in a patient with cervical carcinoma receiving combined radiochemotherapy.

CASE REPORT: A 45-year-old patient with cervix carcinoma received combined radiochemotherapy including cisplatin. After a cumulative dose of 240 mg/m(2) the patient suddenly became somnolent and developed a severe tetraparesis and generalized seizures. After ruling out intracranial bleeding, cerebral metastases as well as infectious and metabolic causes of this condition, a severe toxic encephalopathy was diagnosed based on the clinical findings and MRI scans. After symptomatic treatment on the intensive care unit all symptoms were completely reversible. CONCLUSION: Toxic encephalopathy is a rare but dramatic complication of various cytostatic drugs. With the widespread use of cisplatin this rare disorder should be kept in mind.

Cellular and network mechanisms of spike-wave seizures.

Spike-wave seizures are often considered a relatively "pure" form of epilepsy, with a uniform defect present in all patients and involvement of the whole brain homogeneously. Here, we present evidence against these common misconceptions. Rather than a uniform disorder, spike-wave rhythms arise from the normal inherent network properties of brain excitatory and inhibitory circuits, where they can be provoked by many different insults in several different brain networks. Here we discuss several different cellular and molecular mechanisms that may contribute to the generation of spike-wave seizures, particularly in idiopathic generalized epilepsy. In addition, we discuss growing evidence that electrical, neuroimaging, and molecular changes in spike-wave seizures do not involve the entire brain homogeneously. Rather, spike-wave discharges occur selectively in some thalamocortical networks, while sparing others. It is hoped that improved understanding of the heterogeneous defects and selective brain regions involved will ultimately lead to more effective treatments for spike-wave seizures.

Antiepileptic effects of botulinum neurotoxin E.

Experimental studies suggest that the delivery of antiepileptic agents into the seizure focus might be of potential utility for the treatment of focal-onset epilepsies. Botulinum neurotoxin E (BoNT/E) causes a prolonged inhibition of neurotransmitter release after its specific cleavage of the synaptic protein synaptosomal-associated protein of 25 kDa (SNAP-25). Here, we show that BoNT/E injected into the rat hippocampus inhibits glutamate release and blocks spike activity of pyramidal neurons. BoNT/E effects persist for at least 3 weeks, as determined by immunodetection of cleaved SNAP-25 and loss of intact SNAP-25. The delivery of BoNT/E to the rat hippocampus dramatically reduces both focal and generalized kainic acid-induced seizures as documented by behavioral and electrographic analysis. BoNT/E treatment also prevents neuronal loss and long-term cognitive deficits associated with kainic acid seizures. Moreover, BoNT/E-injected rats require 50% more electrical stimulations to reach stage 5 of kindling, thus indicating a delayed epileptogenesis. We conclude that BoNT/E delivery to the hippocampus is both antiictal and antiepileptogenic in experimental models of epilepsy.

Severe hyperphosphatemia and hypocalcemia following the rectal administration of a phosphate-containing Fleet pediatric enema.

BACKGROUND: Toxicity secondary to rectally administered hypertonic phosphate solution in patients with normal renal function is rarely reported in the literature. We report a case of electrolyte disturbance and seizure secondary to the rectal administration of 2 Fleet pediatric enemas. CASE REPORT: A 4-year-old white female with spinal muscular atrophy and chronic constipation was brought to the emergency department with complaints of lethargy and difficulty breathing following the administration of 2 Fleet pediatric enemas. In the emergency department, physical examination was significant for a depressed level of consciousness and shallow respirations. A basic metabolic profile was significant for a calcium of 3.3 mg/dL, phosphate of 23 mg/dL, and sodium of 153 mEq/L. Arterial blood gases revealed a pH of 7.24, Pco2 of 38 mm Hg, Po2 of 220 mm Hg. Electrocardiogram revealed a prolonged QT interval of 340 milliseconds with a corrected QT interval of 498 milliseconds. Sixteen hours postexposure, she experienced a generalized seizure unresponsive to multiple doses of lorazepam and responsive only to 100 mg of intravenous calcium chloride. Two days after presentation, the patient experienced complete resolution of symptoms. CONCLUSION: Osmotically acting hypertonic phosphate enemas can result in severe toxicity if retained. This is true even in patients without predisposing risk factors.

Right-sided vagus nerve stimulation reduces generalized seizure severity in rats as effectively as left-sided.

As currently utilized, vagus nerve stimulation (VNS) is applied to the cervical trunk of the left vagus nerve to suppress seizures clinically. Demonstration that VNS can also reduce seizure severity when electrodes are placed on the right cervical vagus nerve in rats would provide empirical evidence that the antiepileptic effects of VNS are not an exclusive property of the left vagus nerve. Rats were implanted with a custom cuff electrode on either the left or right cervical vagus nerve. Two days later, continuous VNS was begun in half the rats with left-sided and half with right-sided electrodes. The remaining rats were connected to the stimulator, but did not receive VNS. After 30s, pentylenetetrazole (PTZ) was administered systemically and seizures were rated by a blinded observer. The PTZ test was repeated two days later, with VNS administered to the previously unstimulated rats, while the others received no stimulation. VNS significantly reduced the severity of PTZ-induced seizures in rats regardless of the side of stimulation as compared to their no-VNS (control condition) seizure severity. No significant differences in efficacy existed based on the side of stimulation. These results indicate that right-sided VNS in rats is just as effective as left-sided VNS, suggesting that fibers necessary for seizure suppression are not unique to the left vagus nerve.

The effect of electrical stimulation of the subthalamic nucleus on seizures is frequency dependent.

PURPOSE: Animal studies and anecdotal human case reports have indicated that the subthalamic nucleus (STN) may be a site of anticonvulsant action. METHODS: We tested the hypothesis that continuous electrical stimulation of the STN inhibits seizures acutely. We determined the effects of three stimulation frequencies, 130 Hz, 260 Hz, and 800 Hz, on generalized clonic and tonic-clonic flurothyl seizures. Adult male rats were implanted with concentric bipolar stimulating electrodes in the STN bilaterally. After recovery, rats underwent flurothyl seizures to compare the effects of each stimulation frequency on seizure threshold. Rats were tested 4 times, twice in the stimulated condition, and twice in the unstimulated condition. The order of trials was random, except that stimulation trials alternated with control trials. Flurothyl seizure thresholds under each stimulation condition were compared with control values from the same animal. RESULTS: Bilateral stimulation of the STN at 130 Hz produced a significant increase in the seizure threshold for clonic flurothyl seizures, whereas stimulation at 260 Hz did not appear to have any effect on seizures. STN stimulation at 800 Hz significantly lowered seizure threshold for tonic-clonic seizures. CONCLUSIONS: We conclude that electrical stimulation of the STN can be anticonvulsant, but the effects appear to depend on the stimulation frequency and the type of seizure.

Anticonvulsant activities of the FS-1 subfraction isolated from roots of Delphinium denudatum.

Delphinium denudatum Wall. (Ranunculaceae) is a medicinal herb used for the treatment of epilepsy in the subcontinent. The present study reports the anticonvulsant activities in the maximal electroshock test (MEST) and subcutaneous pentylenetetrazole (PTZ), bicuculline (BIC), picrotoxin (PIC)-induced seizures of the FS-1 subfraction (FS-1) that was obtained by purification of an aqueous fraction isolated from the roots of D. denudatum. In CF 1 mice, FS-1 (600 mg/kg i.p.) exhibited very potent anticonvulsant activity that was comparable to the effects of the well-known antiepileptic drug phenytoin (20 mg/kg) in MEST and protected 100% animals from hind limb tonic extension phase of this model. FS-1 also suppressed PTZ-induced threshold seizure and the loss of the righting reflex with tonic fore and hind limb extension by 100%, similar to the antiepileptic drug valproic acid (350 mg/kg). BIC-induced seizures were suppressed in 80% of the animals. FS-1 exhibited weak anticonvulsant effect on PIC-induced seizures, however, it significantly reduced mortality and delayed the onset of seizures. FS-1 had no effect on strychnine (STN)-induced extensor seizures. The results demonstrate the broad and potent anticonvulsant activity of the compounds in FS-1 of D. denudatum.

A case of pharmacokinetic interference in comedication of clozapine and valproic acid.

In 4-6% of treatment histories, clozapine induces generalized seizures by reducing the seizure threshold. Despite the knowledge of high risks combined therapy (such as bone marrow suppression, pathological EEG changes), some authors even suggest the prophylactic combination with anticonvulsants in high dose treatment of clozapine. We report a case of a 33-year-old female patient, a heavy smoker, suffering from mixed schizoaffective disorder from 1989 onwards. At her 8th admission in 1998, she was rehospitalized after experiencing her first generalized seizure under clozapine treatment, although no seizure phenomenon or other relevant side-effects under several previous clozapine therapies had been observed. Therefore, she received a valproic acid co-medication during her clozapine therapy. Based on therapeutic drug monitoring of clozapine (weekly) under compliance-controlled conditions, the serum levels of clozapine significantly decreased, probably induced by valproic acid. According to the literature, this case report might support the clinical relevance of therapeutic drug monitoring when clozapine therapy is combined with valproic acid as co-medication.

Hyposexuality produced by temporal lobe epilepsy in the cat.

PURPOSE: The hypothesis tested in this study was that a unilateral irritative focal epileptic lesion in the temporal lobe results in hyposexuality. METHODS: Focal epilepsy was produced in male cats by unilateral injection of aluminum hydroxide into either the basolateral amygdala (temporal lobe group) or anterior sigmoid gyrus (motor cortex group). Weekly sex testing trials with estrous females were conducted prior to and after aluminum hydroxide injection, and mating performance scores were compared with those of normal, unoperated cats (normal control group). RESULTS: All animals receiving aluminum hydroxide developed electroencephalographic and behavioral manifestations of epilepsy; i.e., interictal EEG spiking and partial or generalized seizures. Cats in the temporal lobe group exhibited a dramatic and complete suppression of sexual behavior at periods from 6 to 26 weeks after aluminum hydroxide injection. The duration of the hyposexuality varied between individual animals and returned to normal as suddenly as the onset occurred, despite the use of AEDs to prevent or control generalized seizure activity. Interictal EEG epileptiform spiking in the amygdala preceded the onset of hyposexuality by 1-12 weeks. By contrast, cats in the motor cortex and normal control groups showed no sign of sexual dysfunction throughout the experimental period, independent of seizure activity and/or antiepileptic drug (AED) treatment. CONCLUSIONS: These data support the hypothesis that hyposexuality occurs as a result of epileptiform activity in the temporal lobe, but not in the motor cortex. The precise mechanisms by which this occurs are unknown, but are likely to involve abnormally high-frequency neuronal activity in temporal lobe structures known to connect with and/or to regulate hypothalamic nuclei that organize male sexual behavior toward receptive females.

[The delta sleep-inducing peptide, its analogs and the serotoninergic system in the development of anticonvulsant action]. / Del'ta-son indutsiruiushchii peptid, ego analogi i serotoninergicheskaia sistema v razvitii protivosudorozhnogo deistviia.

A seizure-protecting effect of the delta-sleep-inducing peptide (DSIP) and its analogues was revealed. An intensive sorption of H3 tryptophan occurred under the effect of the DSIP and its analogues. The data obtained suggests that the serotoninergic system plays no important part in the seizure-protecting effect.

Frontal cortex leads other brain structures in generalised spike-and-wave spindles and seizure spikes induced by picrotoxin.

Generaliszed spike-and-wave (SW) spindles (5-7 Hz) associated with myoclonic jerks precede the occurrence of regular spikes (2-3 Hz) associated with convulsive seizure induced by picrotoxin. SW spindles occur spontaneously in rodent and cat under some experimental conditions and are considered to be models of human generalised epilepsy. These spindles have been proposed as being led by a thalamic pacemaker. To examine this possibility in picrotoxin-induced SW spindles and seizure spikes, we recorded EEG using chronically implant unipolar electrodes during intravenous picrotoxin infusion in freely behaving rat. The 6 EEG signals were digitally sampled at 1000 Hz. Linear correlation, spectral, coherence and phase analyses were undertaken to determine time differences (TDs) between EEG channels and the brain structure leading seizure activity. One frontal cortex led all other structures during SW spindles. TD between SW spindles in the leading frontal cortex (Fr1) and the contralateral Fr1 was 3.6 + / - 0.5 msec. All ipsilateral structures (hippocampus, thalamus, amygdala, caudate nucleus and occipital cortex) were delayed by more than 3 msec from Fr1 (intralaminar thalamic nuclei - by 6.3 + / - 0.9 msec). TDs of SW spindles between subcortical regions were less than 1.5 msec. Similar relationships with slightly smaller TDs were found with spikes during convulsive seizure except TDs between frontal cortices did not significantly differ from zero. We suggest that seizure activity induced by picrotoxin is led by one Fr1 during SW spindles and by both frontal cortices working as one system during convulsive seizure.

Cholinergic mechanisms in generalized seizures: importance of the zona incerta.

OBJECTIVE: Stimulation of the central cholinergic system results in generalized epileptic seizures. The goal of this study was to map the epileptogenic effects of the cholinergic agonist, carbachol injected into different sites of the basal forebrain and diencephalon of the rat brain. METHODS: Carbachol was injected directly into the brain in a dose of 1 or 3 micrograms. Seizures were assessed behaviourally on a five-stage scale with electroencephalographic controls. Seizures at stage 1 were the least severe and those at stage 5 the most severe. RESULTS: Injections of high dose carbachol (3 micrograms) induced seizures from 40% of all injected brain sites. Injections of low dose carbachol (1 microgram) or isotonic saline into the same brain sites did not cause any behavioural or electrographic seizures. The majority of sites (84%) producing generalized seizures (stage 5) were concentrated in or around the zona incerta. CONCLUSIONS: Within the anatomical limits of the study, the zona incerta is the area most sensitive to carbachol-induced generalized seizures.

The effects of chronic treatment with a calcium channel antagonist on two types of generalized epilepsies in rats.

Although calcium antagonists possess antiepileptic properties in various models of epilepsy, their role after chronic administration and in models for generalized absence epilepsy has not been studied. Twenty-four male Wistar rats, aged 84-94 weeks, were chronically provided with EEG electrodes. Two groups received dietary nimodipine (860 ppm) for 14 and 21 weeks, respectively, while a control group received the same rat chow without nimodipine. The EEG was recorded for 3 h to establish the effects of nimodipine on spike-wave discharges. Next, 50 mg/kg pentylenetetrazol (PTZ) was injected to establish the effects on convulsive epilepsy, and the EEG was recorded for 30 min. All animals had spontaneous spike-wave discharges (SWD), but there were no differences between the three groups. However, chronic nimodipine treatment had a significant effect on PTZ-induced seizures: the group that had been treated with nimodipine for 21 weeks showed significantly more and longer-lasting seizures than the control group. The facilitating effects of chronically administered of nimodipine on PTZ-induced seizures are striking and opposite to those reported in the literature. In a second study, nimodipine was administered acutely, but no effects of nimodipine on PTZ-induced epilepsy could be detected. It can be concluded that chronic dietary administration of a calcium antagonist induces different effects on PTZ-induced seizures than acute administration in aged Wistar rats with spontaneous occurring SWD.

[A model for the study of CNS excitability (the potentials for research on the antiepileptic activity of preparations in a chronic experiment)]. / Model' izucheniia vozbudimosti TsNS (vozmozhnosti issledovaniia protivoépilepticheskoi aktivnosti preparatov v usloviiakh khronicheskogo opyta.

The proposed model is required to study the level of CNS excitability in chronic experiment. Series of subcutaneous subconvulsant doses of corazole, 10 mg/kg, are repeated throughout the whole experiment. Each series of injections is given until generalized convulsions develop, thereafter the mean convulsant dose the convulsant is calculated in the given experiment session. This dose indirectly reflects the level of CNS excitability. The simultaneous administration of anticonvulsants enables evaluation of their efficiency for unlimited periods.

[The antiepileptic effects of the combined action of the new 1,4-dihydropyridine derivative glutapyrone with sodium valproate and phenobarbital]. / Antiépilepticheskie éffekty sochetannogo vozdeistviia novogo proizvodnogo 1,4-digidropirina glutapirona s val'proatom natriia i fenobarbitalom.

Antiepileptic effects of a novel amino acid-containing 1,4-dihydropyridine glutapyrone and sodium valproate during combined therapy on generalized pentylenetetrazol- and focal 4-aminopyridine-induced epileptic activity in rat brain cortex were studied, as were combined effects of glutapyrone and phenobarbital on maximal electroshock in mice. The results of these investigations suggest that combined treatment by glutapyrone and sodium valproate or phenobarbital is reasonable and helps potentiate the effect of each drug, thus significantly reducing their doses, and minimize the risk of side effects of the drugs id used in higher doses in case of long treatment.