Electrophysiological and Neurochemical Assessment of Selenium Alone or Combined with Carbamazepine in an Animal Model of Epilepsy.

The present study aims to evaluate the efficacy of selenium (Se) alone or combined with carbamazepine (CBZ) against the adverse effects induced by the chemoconvulsant pentylenetetrazole (PTZ) in the cortex of adult male rats. Electrocorticogram (ECoG) and oxidative stress markers were implemented to evaluate the differences between treated and untreated animals. Animals were divided into five groups: control group that received i.p. saline injection, PTZ-treated group that received a single i.p. injection of PTZ (60 mg/kg) for induction of seizures followed by a daily i.p. injection of saline, Se-treated group that received an i.p. injection of sodium selenite (0.3 mg/kg/day) after PTZ administration, CBZ-treated group that received orally CBZ (80 mg/kg/day) after PTZ administration, and combination (Se plus CBZ)-treated group that received an oral administration of CBZ (80 mg/kg/day) followed by an i.p. injection of sodium selenite (0.3 mg/kg/day) after PTZ administration. Quantitative analyses of the ECoG indices and the neurochemical parameters revealed that Se and CBZ have mitigated the adverse effects induced by PTZ. The main results were decrease in the number of epileptic spikes, restoring the normal distribution of slow and fast ECoG frequencies and attenuation of most of the oxidative stress markers. However, there was an increase in lipid perioxidation marker in combined treatment of CBZ and Se. The electrophysiological and neurochemical data proved the potential of these techniques in evaluating the treatment's efficiency and suggest that supplementation of Se with antiepileptic drugs (AEDs) may be beneficial in ameliorating most of the alterations induced in the brain as a result of seizure insults and could be recommended as an adjunct therapy with AEDs.

Increased Antiseizure Effectiveness with Tiagabine Combined with Sodium Channel Antagonists in Mice Exposed to Hyperbaric Oxygen.

Hyperbaric oxygen (HBO2) is acutely toxic to the central nervous system, culminating in EEG spikes and tonic-clonic convulsions. GABA enhancers and sodium channel antagonists improve seizure latencies in HBO2 when administered individually, while combining antiepileptic drugs from different functional classes can provide greater seizure latency. We examined the combined effectiveness of GABA enhancers (tiagabine and gabapentin) with sodium channel antagonists (carbamazepine and lamotrigine) in delaying HBO2-induced seizures. A series of experiments in C57BL/6 mice exposed to 100% oxygen at 5 atmospheres absolute (ATA) were performed. We predicted equally effective doses from individual drug-dose response curves, and the combinations of tiagabine + carbamazepine or lamotrigine were tested to determine the maximally effective combined doses to be used in subsequent experiments designed to identify the type of pharmacodynamic interaction for three fixed-ratio combinations (1:3, 1:1, and 3:1) using isobolographic analysis. For both combinations, the maximally effective combined doses increased seizure latency over controls > 5-fold and were determined to interact synergistically for fixed ratios 1:1 and 3:1, additive for 1:3. These results led us to explore whether the benefits of these drug combinations could be extended to the lungs, since a centrally mediated mechanism is believed to mediate hyperoxic-induced cardiogenic lung injury. Indeed, both combinations attenuated bronchoalveolar lavage protein content by ~ 50%. Combining tiagabine with carbamazepine or lamotrigine not only affords greater antiseizure protection in HBO2 but also allows for lower doses to be used, minimizing side effects, and attenuating acute lung injury.

Effects of sinapic acid on hepatic cytochrome P450 3A2, 2C11, and intestinal P-glycoprotein on the pharmacokinetics of oral carbamazepine in rats: Potential food/herb-drug interaction.

Dietary supplements, herbal medicines, and other foods may affect the pharmacokinetics and/or pharmacodynamics of carbamazepine (CBZ), which may possibly lead to potential drug-drug/herb-drug interactions, as CBZ has a narrow therapeutic window. Sinapic acid (SA) is a bioactive phytoconstituent used as a dietary supplement for the treatment of epilepsy. This study determined the effects of SA on the pharmacokinetics of CBZ and proposed a possible interaction mechanism in twenty-four male wistar rats (180-210 g). A single CBZ dose (80 mg/kg) was administered orally to rats with or without SA pretreatment (20 mg/kg p.o. per day for 7 days, n = 6). The CBZ concentration in plasma samples was determined by using a sensitive reversed-phase high-performance liquid chromatography assay. The pharmacokinetic parameters were calculated by using non-compartmental analysis. Significance was determined through Dunnett's multiple comparison test or one-way analysis of variance as appropriate; p < 0.05 were considered significant. The change in the pharmacokinetic parameters (Cmax, Tmax, AUC0-t, AUC0-∞, T½, and kel) of CBZ was evaluated after the administration of CBZ alone or after CBZ co-administration with SA pretreatment. The plasma concentration of CBZ was higher after SA pretreatment than that without pretreatment. The pharmacokinetics of orally administered CBZ were found to be significantly altered (p < 0.05) in rats pretreated with SA compared to those in rats administered CBZ alone. The increases in the Cmax, AUC0-t, T1/2, and MRT of CBZ were 29.79%, 57.18%, 77.18%, and 58.31%, respectively, whereas the kel and apparent oral CL/F were significantly reduced (p < 0.05) in rats pretreated with SA compared to those in rats not pretreated with SA (43.87% and 42.50%, respectively). However, no significant change was observed in the Tmax of CBZ in rats pretreated with SA compared to that in rats that did not receive pretreatment. The enhancement in Cmax, AUC0-t, T1/2, and MRT and the reduction in Kel and CL/F values resulted from the significant inhibition of CYP3 A2, the CYP2C11-mediated metabolism of CBZ in the liver, and the inhibition of intestinal P-glycoprotein/MDR1, which enhanced the rate of CBZ absorption. Further studies are required to determine the clinical relevance of these observations.

Alterations in Pharmacokinetics of Orally Administered Carbamazepine in Rats Treated with Sodium alginate: Possible Interaction between Therapeutic Drugs and Semi-solid Enteral Nutrients.

OBJECTIVE: The use of enteral nutrients plays an extremely important role in accurate nutrition management. Sodium alginate (SA) is frequently used for the semi-solidification of enteral nutrients. In the present study, we investigated whether the pharmacokinetic profile of orally administered carbamazepine (CBZ) is altered by a treatment with SA immediately before and after dosing of the drug. Furthermore, the adsorption effects of SA on CBZ were examined using an in vitro analysis. METHOD: SA was orally administered to rats just before and immediately after CBZ dosing. The CBZ concentration profile following its oral administration was analyzed by a non-compartmental method. The adsorption of CBZ onto SA was evaluated after centrifugation using an ultrafiltration device. FINDINGS: The serum concentration of orally administered CBZ at each sampling point was reduced by the treatment with SA, and the extent of the decrease observed in the concentration of CBZ was larger when SA was ingested immediately after administration of the drug, which was consistent with the alteration observed in the value of the area under the curve (AUC). No significant differences were noted in the elimination rate at the terminal phase (ke) among the groups. In the in vitro assay, CBZ was adsorbed by SA in the solution used to reflect fluid in the intestinal tract. CONCLUSIONS: The pharmacological efficacies of CBZ might be reduced by SA through the pharmacokinetic interactions, and that the careful attention should be paid to the timing of administration of CBZ and semi-solid enteral nutrients.

A pilot study of neuromuscular electrical stimulation for neuropathic pain caused by spinal cord injury.

This pilot study retrospectively investigated the feasible effect and safety of neuromuscular electrical stimulation (NMES) for the management of neuropathic pain (NPP) caused by spinal cord injury (SCI).A total of 54 patient cases with NPP after SCI were included. Of these, 27 cases underwent carbamazepine plus NMES treatment, and were assigned to an NMES group; while the other 27 cases received carbamazepine only, and were assigned to a control group. The primary outcome of pain intensity was measured by numerical rating scale (NRS). The secondary outcome of quality of life was measured by the Short Form 36 (SF-36) Scale. Furthermore, adverse events were also documented in this study. All outcomes were measured and analyzed before and after 3-month treatment.After 3-month treatment, the cases in the NMES group neither reduced the pain intensity of NPP, measured by the NRS (P > .05), nor improved the quality of life, measured by the SF-36 (P > .05), compared with cases in the control group. Moreover, both groups had similar adverse events.The results of this study showed that NMES might be not efficacious for NPP caused by SCI after 3 months treatment with quite low intervention dose.

In vitro and in vivo effects of selected fibers on the pharmacokinetics of orally administered carbamazepine: Possible interaction between therapeutic drugs and semisolid enteral nutrients.

OBJECTIVE: The management of nutrition using semisolid enteral nutrients is considered useful for avoiding the adverse effects associated with liquid enteral nutrients. In the present study, we used an in vitro analysis to investigate whether carbamazepine (CBZ) is adsorbed by the fibers included in semisolid enteral nutrients. The effects of these fibers on the pharmacokinetic profile of CBZ following its oral administration were also examined in rats. METHODS: The adsorption of CBZ onto fibers was examined by absorbance monitoring of the filtrate after centrifugation using an ultrafiltration device. Viscosities of each solution were measured by rotational viscosimeter. The CBZ concentration profile after its oral administration (50 mg/kg) was analyzed by a noncompartmental method. RESULTS: In the two solutions used to reflect gastric juice and fluid in the intestinal tract, CBZ was more strongly adsorbed by water-soluble fibers (guar gum and xanthan gum) than by insoluble fibers (dextrin hydrate). The adsorption of CBZ also was observed even if the concentrations of guar gum and xanthan gum were reduced to such an extent that viscosity was 0 Paï½¥s. The pharmacokinetic examination of orally administered CBZ revealed that the area under the curve was significantly lower in the guar gum and xanthan gum groups than in the control group. CONCLUSION: CBZ was adsorbed by fibers used for the semisolidification of enteral nutrients, which may be partially responsible for the alterations observed in the pharmacokinetic profile of CBZ.

Mood-Stabilizing Anticonvulsants, Spina Bifida, and Folate Supplementation: Commentary.

PURPOSE/BACKGROUND: High risks of neural tube defects and other teratogenic effects are associated with exposure in early pregnancy to some anticonvulsants, including in women with bipolar disorder. METHODS/PROCEDURES: Based on a semistructured review of recent literature, we summarized findings pertaining to this topic. FINDINGS/RESULTS: Valproate and carbamazepine are commonly used empirically (off-label) for putative long-term mood-stabilizing effects. Both anticonvulsants have high risks of teratogenic effects during pregnancy. Risks of neural tube defects (especially spina bifida) and other major malformations are especially great with valproate and can arise even before pregnancy is diagnosed. Standard supplementation of folic acid during pregnancy can reduce risk of spontaneous spina bifida, but not that associated with valproate or carbamazepine. In contrast, lamotrigine has regulatory approval for long-term use in bipolar disorder and appears not to have teratogenic effects in humans. IMPLICATIONS/CONCLUSIONS: Lack of protective effects against anticonvulsant-associated neural tube defects by folic acid supplements in anticipation of and during pregnancy is not widely recognized. This limitation and high risks of neural tube and other major teratogenic effects, especially of valproate, indicate the need for great caution in the use of valproate and carbamazepine to treat bipolar disorder in women of child-bearing age.

Psychotropic drugs attenuate lipopolysaccharide-induced hypothermia by altering hypothalamic levels of inflammatory mediators in rats.

Recent evidence suggests that inflammation may contribute to the pathophysiology of mental disorders and that psychotropic drugs exert various effects on brain inflammation. The administration of bacterial endotoxin (lipopolysaccharide, LPS) to mammals is associated with robust production of inflammatory mediators and pathological changes in body temperature. The objective of the present study was to examine the effects of four different psychotropic drugs on LPS-induced hypothermia and production of prostaglandin (PG) E2, tumor necrosis factor (TNF)-α and phosphorylated-p65 (P-p65) levels in hypothalamus of LPS-treated rats. Rats were treated once daily with lithium (100mg/kg), carbamazepine (40mg/kg), haloperidol (2mg/kg), imipramine (20mg/kg) or vehicle (NaCl 0.9%) for 29 days. On day 29, rats were injected with LPS (1mg/kg) or saline. At 1.5h post LPS injection body temperature was measured, rats were sacrificed, blood was collected and their hypothalami were excised, homogenized and centrifuged. PGE2, TNF-α and nuclear P-p65 levels were determined by specific ELISA kits. We found that lithium, carbamazepine, haloperidol and imipramine significantly attenuated LPS-induced hypothermia, resembling the effect of classic anti-inflammatory drugs. Moreover, lithium, carbamazepine, haloperidol and imipramine differently but significantly affected the levels of PGE2, TNF-α and P-p65 in plasma and hypothalamus of LPS-treated rats. The results suggest that psychotropic drugs attenuate LPS-induced hypothermia by reducing hypothalamic production of inflammatory constituents, particularly PGE2. The effects of psychotropic drugs on brain inflammation may contribute to their therapeutic mechanism but also to their toxicological profile.

Oral exposure to immunostimulating drugs results in early changes in innate immune parameters in the spleen.

The development of immune-dependent drug hypersensitivity reactions (IDHR) is likely to involve activation of the innate immune system to stimulate neo-antigen specific T-cells. Previously it has been shown that, upon oral exposure to several drugs with immune-adjuvant capacity, mice developed T-cell-dependent responses to TNP-OVA. These results were indicative of the adjuvant potential of these drugs. The present study set out to evaluate the nature of this adjuvant potential by focusing on early immune changes in the spleen, by testing several drugs in the same experimental model. Mice were exposed to one or multiple oral doses of previously-tested drugs: the non-steroidal-anti-inflammatory drug (NSAID) diclofenac (DF), the analgesic acetaminophen (APAP), the anti-epileptic drug carbamazepine (CMZ) or the antibiotic ofloxacin (OFLX). Within 24 h after the final dosing, early innate and also adaptive immune parameters in the spleen were examined. In addition, liver tissue was also evaluated for damage. Exposure to APAP resulted in severe liver damage, increased levels of serum alanine aminotransferase (ALT) and local MIP-2 expression. DF exposure did not cause visible liver damage, but did increase liver weight. DF also elicited clear effects on splenic innate and adaptive immune cells, i.e. increased levels of NK cells and memory T-cells. Furthermore, an increase in plasma MIP-2 levels combined with an influx of neutrophils into the spleen was observed. OFLX and CMZ exposure resulted in increased liver weights, MIP-2 expression and up-regulation of co-stimulatory molecules on antigen-presenting cells (APC). The data suggested that multiple immune parameters were altered upon exposure to drugs known to elicit immunosensitization and that broad evaluation of immune changes in straightforward short-term animal models is needed to determine whether a drug may harbor the hazard to induce IDHR. The oral exposure approach as used here may be applied in the future as an immunotoxicological research tool in this type of evaluation.

IQ at 6 years after in utero exposure to antiepileptic drugs: a controlled cohort study.

OBJECTIVE: To delineate the risk to child IQ associated with frequently prescribed antiepileptic drugs. METHODS: Children born to women with epilepsy (n = 243) and women without epilepsy (n = 287) were recruited during pregnancy and followed prospectively. Of these, 408 were blindly assessed at 6 years of age. Maternal and child demographics were collected and entered into statistical models. RESULTS: The adjusted mean IQ was 9.7 points lower (95% confidence interval [CI] -4.9 to -14.6; p < 0.001) for children exposed to high-dose (>800 mg daily) valproate, with a similar significant effect observed for the verbal, nonverbal, and spatial subscales. Children exposed to high-dose valproate had an 8-fold increased need of educational intervention relative to control children (adjusted relative risk, 95% CI 8.0, 2.5-19.7; p < 0.001). Valproate at doses <800 mg daily was not associated with reduced IQ, but was associated with impaired verbal abilities (-5.6, 95% CI -11.1 to -0.1; p = 0.04) and a 6-fold increase in educational intervention (95% CI 1.4-18.0; p = 0.01). In utero exposure to carbamazepine or lamotrigine did not have a significant effect on IQ, but carbamazepine was associated with reduced verbal abilities (-4.2, 95% CI -0.6 to -7.8; p = 0.02) and increased frequency of IQ <85. CONCLUSIONS: Consistent with data from younger cohorts, school-aged children exposed to valproate at maternal doses more than 800 mg daily continue to experience significantly poorer cognitive development than control children or children exposed to lamotrigine and carbamazepine.

Functional drug screening reveals anticonvulsants as enhancers of mTOR-independent autophagic killing of Mycobacterium tuberculosis through inositol depletion.

Mycobacterium tuberculosis (MTB) remains a major challenge to global health made worse by the spread of multidrug resistance. We therefore examined whether stimulating intracellular killing of mycobacteria through pharmacological enhancement of macroautophagy might provide a novel therapeutic strategy. Despite the resistance of MTB to killing by basal autophagy, cell-based screening of FDA-approved drugs revealed two anticonvulsants, carbamazepine and valproic acid, that were able to stimulate autophagic killing of intracellular M. tuberculosis within primary human macrophages at concentrations achievable in humans. Using a zebrafish model, we show that carbamazepine can stimulate autophagy in vivo and enhance clearance of M. marinum, while in mice infected with a highly virulent multidrug-resistant MTB strain, carbamazepine treatment reduced bacterial burden, improved lung pathology and stimulated adaptive immunity. We show that carbamazepine induces antimicrobial autophagy through a novel, evolutionarily conserved, mTOR-independent pathway controlled by cellular depletion of myo-inositol. While strain-specific differences in susceptibility to in vivo carbamazepine treatment may exist, autophagy enhancement by repurposed drugs provides an easily implementable potential therapy for the treatment of multidrug-resistant mycobacterial infection.

Effect of Sophora flavescens on the pharmacokinetics of carbamazepine in rats.

Carbamazepine (CBZ), an antiepileptic with narrow therapeutic window, is a substrate of CYP 3A4 which metabolizes CBZ to carbamazepine-10,11-epoxide (CBZE). CBZE is an active and toxicity metabolite, and it is a substrate of MRP-2. Using CBZ for a long time can cause hepatic injury. Sophora flavescens (SF) is a medicinal herb used for the protected hepatic injury. This study investigated the acute and chronic effects of SF on the pharmacokinetics of CBZ in rats. The concentrations of CBZ and CBZE in plasma and tissues were determined by HPLC method. The results showed that SF which significantly decreased the AUC0-t of CBZ, increased CBZE conversely. Tissue analysis showed that the concentrations of CBZ and CBZE in brain and liver were decreased by SF. In addition, the distribution of CBZE in kidney was reduced significantly, which influenced the CBZE excretion and increased the drug toxic potentially. Results in the current study suggest that patients using CBZ might be cautioned in the use of SF extract or Sophora-derived products. Meanwhile, patients receiving drugs which are substrates of CYP 3A4 and/or MRP-2 should be advised of the potential herb-drug interaction to reduce the risk of therapeutic failure or increased toxicity of conventional drug therapy.

Clinical Pharmacogenetics Implementation Consortium guidelines for HLA-B genotype and carbamazepine dosing.

Human leukocyte antigen B (HLA-B) is a gene that encodes a cell surface protein involved in presenting antigens to the immune system. The variant allele HLA-B*15:02 is associated with an increased risk of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) in response to carbamazepine treatment. We summarize evidence from the published literature supporting this association and provide recommendations for the use of carbamazepine based on HLA-B genotype (also available on PharmGKB: http://www.pharmgkb.org). The purpose of this article is to provide information to allow the interpretation of clinical HLA-B*15:02 genotype tests so that the results can be used to guide the use of carbamazepine. The guideline provides recommendations for the use of carbamazepine when HLA-B*15:02 genotype results are available. Detailed guidelines regarding the selection of alternative therapies, the use of phenotypic tests, when to conduct genotype testing, and cost-effectiveness analyses are beyond the scope of this document. Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines are published and updated periodically on the PharmGKB website at (http://www.pharmgkb.org).

Brain anticonvulsant protection of mice given chronic carbamazepine under various fatty acid and magnesium diet conditions.

The anticonvulsant and mood stabilizer drug carbamazepine (CBZ) was evaluated for anti-seizure activity after drug pretreatment of young weaning mice given various oil-based diets. These diets had various mono-(MUFA) and poly-(PUFA) unsaturated fatty acid contents, were associated or not with magnesium deprivation, and were given over the entire experimental period (34 days). The diets included a commercial and three purified synthetic diets (n-6 PUFA, n-3 PUFA and MUFA-based chows containing 5% corn/sunflower oils 1:3, 5% rapeseed oil and 5% high oleic acid sunflower oil/sunflower oil 7:3, respectively). A 10-days CBZ treatment (50 mg/kg/day fragmented in two daily intraperitoneal injections of 25 mg/kg) was given 20 days after initiating diet administration and evaluations of mice was performed 4 days after arrest of CBZ in various seizure tests. In these conditions, CBZ pretreatment still exhibited anticonvulsant protection especially in magnesium-deficient animals. Ethosuximide (ESM)-like profiles under MUFA and n-3 PUFA diets and unusual GABA(A)ergic profile under n-6 PUFA diet in magnesium-deficiency dependent audiogenic seizures (MDDAS) test as well as protection against NMDA-induced seizures in all lipid (n-3 PUFA>MUFA and n-6 PUFA) diet conditions were observed in CBZ-pretreated mice. By highlighting ESM-like and anti-NMDA mechanisms previously induced by an n-3 PUFA diet, present CBZ anticonvulsant properties suggest brain protective targets common to CBZ and n-3 PUFAs.

The effect of vitamin B supplementation on homocysteine metabolism and clinical state of patients with chronic epilepsy treated with carbamazepine and valproic acid.

PURPOSE: To investigate the influence of vitamin B supplementation on the plasma total homocysteine (p-tHcy), serum folate (s-FA), serum B12 (s-B12), and clinical state of patients with chronic epilepsy. METHODS: Beck Depression Inventory (BDI) scores and p-tHcy, s-B12, and s-FA levels were assessed at baseline, after 1 year of supplementation (G1), and before and after 1 year of VPA or CBZ therapy (G2). RESULTS: Eighty-one patients participated in the study: 51 patients with chronic epilepsy (G1) treated with carbamazepine (CBZ) or valproic acid (VPA), and 30 patients with newly diagnosed epilepsy (G2). At baseline, mean p-tHcy level was significantly higher in G1 than G2 (p=0.0001) with no significant differences in s-FA or s-B12 levels. p-tHcy level significantly decreased in CBZ-treated G1 patients (p=0.00002) after 1 year of supplementation and increased in G2 after 1 year of anti-epileptic drug (AED) therapy without supplementation. BDI scores in G1 decreased significantly after 1 year of supplementation (p=0.0001) and increased significantly in VPA-treated G2 patients after 1 year of AED therapy (p=0.02). The number of hyperhomocysteinemic patients significantly decreased in G1 after vitamin B supplementation (p=0.01) and increased in G2 (p=0.002). We also observed improved BDI scores and reduced seizure frequency in patients with chronic epilepsy. CONCLUSIONS: These data support the hypothesis that AEDs play a major role in hyperhomocysteinemia development in patients with epilepsy. Adding folate and vitamin B12 to AED therapy is a safe and inexpensive way to reduce the risk of hyperhomocysteinemia.

Preclinical activity profile of α-lactoalbumin, a whey protein rich in tryptophan, in rodent models of seizures and epilepsy.

PURPOSE: To evaluate the potential anticonvulsant activity of α-lactalbumin (ALAC), a whey protein rich in tryptophan (TRP) relative to other large neutral amino acids (LNAAs), in rodent models of seizures and epilepsy. METHODS: The effects of ALAC administered per os were evaluated by standard protocols against audiogenic seizures in Genetic Epilepsy Prone Rats (GEPR-9 rats), maximal electroshock (MES)-induced seizures in rats, pilocarpine-induced seizures in mice, spontaneous chronic seizures in mice exposed to pilocarpine-induced status epilepticus (SE), and absence seizures in WAG/Rij rats. In some models, carbamazepine (CBZ) was included as an active control. Plasma TRP/LNAAs ratios were measured by GC-MS. RESULTS: Single doses of ALAC up to 500 or 6000 mg/kg were devoid of anticonvulsant activity in all models tested. Conversely, 5- and 12-day treatment with ALAC (250-1000 mg/kg/day) in GEPR rats reduced dose-dependently seizure scores and prolonged latency to clonus onset, with full persistence of the effect for up to 12h. ALAC (125-500 mg/kg/day for 15 days) protected against seizures induced by 250 mg/kg pilocarpine, but was less effective against higher pilocarpine doses. Similarly to CBZ, ALAC (125-500 mg/kg/day for 15 days) was also effective against spontaneous seizures in the post-pilocarpine SE model. ALAC (up to 6000 mg/kg/day for 12 days) did not prevent MES-induced seizures, although it reduced the duration of tonic extension at doses between 250 and 1000 mg/kg/day. Absence seizures in WAG/Rij rats were not significantly affected by ALAC. Plasma TRP/LNAAS ratios increased 2- to 3-fold after dosing with ALAC (250 mg/kg/day) for 7 and 14 days, respectively. CONCLUSIONS: ALAC exerts significant protective activity against seizures in animal models, the effect being especially prominent against audiogenic seizures in GEPR-9 rats, seizures induced by low-dose pilocarpine in mice, and spontaneous seizures in mice exposed to pilocarpine-induced SE. This action is likely to be mediated by increased availability of TRP in the brain, with a consequent increase in 5-HT mediated transmission.

New antiepileptic drugs: molecular targets.

In the past 20 years, a number of new antiepileptic drugs (AEDs) have been introduced and other molecules are in development, some of which are advantageous in terms of pharmacokinetics, tolerability and potential for drug interactions. These drugs are regarded as second generation compared to older agents such as barbiturates, phenytoin, carbamazepine, ethosuximide and valproic acid. Although some of these second generation compounds may be advantageous in terms of kinetics, tolerability and potential for drug interactions, all of them still target voltage-gated channels or GABA-mediated inhibition, predominantly, without any real improvement in epilepsy therapy. Studies on mechanisms of seizure generation and propagation have identified new potential targets for AEDs. The growing understanding of the pathophysiology of epilepsy and the structural and functional characterization of the molecular targets provide many opportunities to create improved epilepsy therapies. In this review the molecular targets for new AEDs are discussed, providing further suggestions on how future research can be improved.

Valproic acid: long-term effects on children exposed in utero.

(1) Numerous follow-up studies of pregnancies in women with epilepsy show that valproic acid is more teratogenic than other antiepileptics. The risk of malformations increases with doses above 1000 mg/day; (2) Malformations associated with valproic acid include neural tube defects in 1-2% of exposed children, as well as urogenital, craniofacial and digital abnormalities. Cardiac disorders and limb defects have also been reported; (3) Convergent results of several cohort studies show that exposure to valproic acid in utero has detrimental effects on intelligence, language and behavior, which appear in school-age children; (4) In practice, the use of valproic acid should be avoided throughout pregnancy, as well as by women of childbearing age not using effective contraception. If a woman is planning pregnancy, the choice of valproic acid should be reassessed with the patient. If valproic acid therapy is maintained, the minimum effective daily dose should be determined and folic acid supplementation initiated.

SUNCT syndrome successfully treated with the combination of oxcarbazepine and gabapentin.

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) is a syndrome of intermittent, brief, unilateral, severe paroxysms of orbital-temporal pain recurring multiple times per day. The pain modulation is often very difficult. The reported SUNCT patient is the first who responded to a combination treatment of oxcarbazepine and gabapentin.

Excitability and gap junction-mediated mechanisms in nucleus accumbens regulate self-stimulation reward in rats.

The nucleus accumbens (Acb) is a part of the striatum which integrates information from cortical and limbic brain structures, and mediates behaviors which reinforce reward. Previous work has suggested that neuronal synchrony mediated by gap junctions in Acb-related areas is involved in brain pleasure and reward. In order to gain insight into functional aspects of the neural information processing at the level of the striatum, we explored the possible role of Acb gap junctional communication and chemical synapses on reward self-stimulation in rats using positive reinforcement. Rats were trained to press a lever that caused an electrical current to be delivered into the hypothalamus, which is recognized to cause pleasure/reward. Intracerebral infusion into the Acb of the gap junctional blocker carbenoxolone (CBX) decreased the lever-pressing activity. Considering that the net effect of blocking gap junctions is a reduced synchronized output of the cellular activities, which at some level represents a decrease in excitability, two other inhibitors of neuronal excitability, carbamazepine (CBZ) and tetrodotoxin (TTX), were infused into the Acb and their effects on lever-pressing assessed. All manipulations that diminished excitability in the Acb resulted in reduced lever-pressing activity. CBX and TTX were also infused into motor cortex mediating forelimb lever-pressing with no effect. However, a manipulation that has the net effect of increasing excitation, the infusion of the opiate antagonist naloxone, also decreased significantly brain self-stimulation. We conclude that reward behaviors depend to a great extent on both excitability and gap junction-mediated mechanisms in Acb neuronal networks. Thus, the Acb provides a site for the study of pleasure/reward, addiction and conscious experience.