Lippia origanoides essential oil possesses anticonvulsant effect in pentylenetetrazol-induced seizures in rats: a behavioral, electroencephalographic, and electromyographic study.

Epilepsy is a neuronal disorder characterized by abnormal excitability of the brain, leading to seizures. Only around 66% of the epileptic patients respond adequately to treatment with existing conventional anticonvulsants, making it necessary to investigate new antiepileptic drugs. The growing research into natural products and their pharmacological properties has become increasingly promising, particularly in the study of essential oils, which are already widely used in popular culture for treating various diseases. The present study evaluated the anticonvulsant effects of Lippia origanoides essential oil (LOEO) (100 mg/kg i. p.) compared to diazepam (DZP) (5 mg/kg i. p.), and the combined administration of these two substances to control convulsions induced by pentylenetetrazol (PTZ) (60 mg/kg i. p.). This evaluation was carried out using 108 male Wistar rats, which were divided into two experiments. Experiment 1-Behavioral assessment: The animals were divided into 4 groups (n = 9): (I) saline solution + PTZ, (II) DZP + PTZ, (III) LOEO + PTZ, (IV) LOEO + DZP + PTZ. The convulsive behavior was induced 30 min after the administration of the tested anticonvulsant drugs, and the observation period lasted 30 min. Experiment 2- Electrocorticographic evaluation: The animals were divided into 8 groups (n = 9): (I) saline solution; (II) LOEO; (III) DZP; (IV) LOEO + DZP; (V) saline + PTZ, (VI) DZP + PTZ (VII) LOEO + PTZ, (VIII) LOEO + DZP + PTZ. PTZ was administered 30 min after LOEO and DZP treatments and electrocorticographic activity was assessed for 15 min. For the control groups, electromyographic recordings were performed in the 10th intercostal space to assess respiratory rate. The results demonstrated that Lippia origanoides essential oil increased the latency time for the appearance of isolated clonic seizures without loss of the postural reflex. The animals had a more intense decrease in respiratory rate when combined with LOEO + DZP. EEG recordings showed a reduction in firing amplitude in the LOEO-treated groups. The combining treatment with diazepam resulted in increased anticonvulsant effects. Therefore, treatment with Lippia origanoides essential oil was effective in controlling seizures, and its combination with diazepam may represent a future option for the treatment of difficult-to-control seizures.

Anticonvulsant effects of desvenlafaxine on modulating brain monoamine and oxidative stress in mice / Efeitos anticonvulsivantes da desvenlafaxina na modulação da monoamina cerebral e do estresse oxidativo em camundongos

Desvenlafaxine succinate (DVS) inhibits serotonin reuptake selectively and is approved for major depressive disorders. This research investigated influence of DVS on modulating brain monoamine and oxidative stress in mice. The antiepileptic potential of DVS (10, 20, or 30 mg/kg/i.p.) in pentylenetetrazole (PTZ; 85 mg/kg) with i.p. route of administration, strychnine (STR; 75 mg/kg) with i.p. route, pilocarpine (400 mg/kg) with s.c. route and maximal electroshock MES-induced convulsion in mouse models. The activities of oxidative stress, i.e. superoxide dismutase (SOD), glutathione (GSH) and lipid peroxidation (LPO) as well as gamma-aminobutyric acid (GABA) in the brains of PTZ-induced convulsive mice. Treatment with DVS increased the latency to develop siezures and declined mortalities in rodents against PTZ, STR and pilocarpine-induced convulsions. Results of MES-leaded siezures revealed that DVS reduced tonic hind limb extension duration and mortalities significantly. Brain, SOD, GSH and GABA level were significantly (P<0.01) increased and LPO reduced significantly (P<0.01) after DVS treatment. Furthermore, the DVS did not show any motor coordination signs in the rotarod test. We demonstrated that the role of DVS in convulsion genesis in mice under control condition and attenuate the PTZ-induced oxidative damage.(AU)

O succinato de desvenlafaxina (DVS) inibe seletivamente a recaptação da serotonina e é aprovado para transtornos depressivos maiores. Esta pesquisa investigou a influência do DVS na modulação da monoamina cerebral e do estresse oxidativo em camundongos. O potencial antiepiléptico de DVS (10, 20 ou 30 mg / kg / i.p.) Em pentilenotetrazole (PTZ; 85 mg / kg) com i.p. via de administração, estricnina (STR; 75 mg / kg) com i.p. via, pilocarpina (400 mg / kg) com s.c. rota e convulsão induzida por MES de eletrochoque máximo em modelos de camundongos. As atividades de estresse oxidativo, ou seja, superóxido dismutase (SOD), glutationa (GSH) e peroxidação lipídica (LPO), bem como ácido gama-aminobutírico (GABA) nos cérebros de camundongos convulsivos induzidos por PTZ. O tratamento com DVS aumentou a latência para desenvolver crises e diminuiu a mortalidade em roedores contra convulsões induzidas por PTZ, STR e pilocarpina. Os resultados de siezures conduzidos por MES revelaram que o DVS reduziu significativamente a duração e a mortalidade da extensão tônica dos membros posteriores. Os níveis de cérebro, SOD, GSH e GABA aumentaram significativamente (P < 0,01) e o LPO reduziu significativamente (P < 0,01) após o tratamento com DVS. Além disso, o DVS não apresentou sinais de coordenação motora no teste do rotarod. Demonstramos o papel do DVS na gênese da convulsão em camundongos sob condição de controle e atenua o dano oxidativo induzido por PTZ.(AU)

Anticonvulsant effects of desvenlafaxine on modulating brain monoamine and oxidative stress in mice / Efeitos anticonvulsivantes da desvenlafaxina na modulação da monoamina cerebral e do estresse oxidativo em camundongos

Desvenlafaxine succinate (DVS) inhibits serotonin reuptake selectively and is approved for major depressive disorders. This research investigated influence of DVS on modulating brain monoamine and oxidative stress in mice. The antiepileptic potential of DVS (10, 20, or 30 mg/kg/i.p.) in pentylenetetrazole (PTZ; 85 mg/kg) with i.p. route of administration, strychnine (STR; 75 mg/kg) with i.p. route, pilocarpine (400 mg/kg) with s.c. route and maximal electroshock MES-induced convulsion in mouse models. The activities of oxidative stress, i.e. superoxide dismutase (SOD), glutathione (GSH) and lipid peroxidation (LPO) as well as gamma-aminobutyric acid (GABA) in the brains of PTZ-induced convulsive mice. Treatment with DVS increased the latency to develop siezures and declined mortalities in rodents against PTZ, STR and pilocarpine-induced convulsions. Results of MES-leaded siezures revealed that DVS reduced tonic hind limb extension duration and mortalities significantly. Brain, SOD, GSH and GABA level were significantly (P<0.01) increased and LPO reduced significantly (P<0.01) after DVS treatment. Furthermore, the DVS did not show any motor coordination signs in the rotarod test. We demonstrated that the role of DVS in convulsion genesis in mice under control condition and attenuate the PTZ-induced oxidative damage.

O succinato de desvenlafaxina (DVS) inibe seletivamente a recaptação da serotonina e é aprovado para transtornos depressivos maiores. Esta pesquisa investigou a influência do DVS na modulação da monoamina cerebral e do estresse oxidativo em camundongos. O potencial antiepiléptico de DVS (10, 20 ou 30 mg / kg / i.p.) Em pentilenotetrazole (PTZ; 85 mg / kg) com i.p. via de administração, estricnina (STR; 75 mg / kg) com i.p. via, pilocarpina (400 mg / kg) com s.c. rota e convulsão induzida por MES de eletrochoque máximo em modelos de camundongos. As atividades de estresse oxidativo, ou seja, superóxido dismutase (SOD), glutationa (GSH) e peroxidação lipídica (LPO), bem como ácido gama-aminobutírico (GABA) nos cérebros de camundongos convulsivos induzidos por PTZ. O tratamento com DVS aumentou a latência para desenvolver crises e diminuiu a mortalidade em roedores contra convulsões induzidas por PTZ, STR e pilocarpina. Os resultados de siezures conduzidos por MES revelaram que o DVS reduziu significativamente a duração e a mortalidade da extensão tônica dos membros posteriores. Os níveis de cérebro, SOD, GSH e GABA aumentaram significativamente (P < 0,01) e o LPO reduziu significativamente (P < 0,01) após o tratamento com DVS. Além disso, o DVS não apresentou sinais de coordenação motora no teste do rotarod. Demonstramos o papel do DVS na gênese da convulsão em camundongos sob condição de controle e atenua o dano oxidativo induzido por PTZ.

Anticonvulsant effects of desvenlafaxine on modulating brain monoamine and oxidative stress in mice

Abstract Desvenlafaxine succinate (DVS) inhibits serotonin reuptake selectively and is approved for major depressive disorders. This research investigated influence of DVS on modulating brain monoamine and oxidative stress in mice. The antiepileptic potential of DVS (10, 20, or 30 mg/kg/i.p.) in pentylenetetrazole (PTZ; 85 mg/kg) with i.p. route of administration, strychnine (STR; 75 mg/kg) with i.p. route, pilocarpine (400 mg/kg) with s.c. route and maximal electroshock MES-induced convulsion in mouse models. The activities of oxidative stress, i.e. superoxide dismutase (SOD), glutathione (GSH) and lipid peroxidation (LPO) as well as gamma-aminobutyric acid (GABA) in the brains of PTZ-induced convulsive mice. Treatment with DVS increased the latency to develop siezures and declined mortalities in rodents against PTZ, STR and pilocarpine-induced convulsions. Results of MES-leaded siezures revealed that DVS reduced tonic hind limb extension duration and mortalities significantly. Brain, SOD, GSH and GABA level were significantly (P 0.01) increased and LPO reduced significantly (P 0.01) after DVS treatment. Furthermore, the DVS did not show any motor coordination signs in the rotarod test. We demonstrated that the role of DVS in convulsion genesis in mice under control condition and attenuate the PTZ-induced oxidative damage.

Resumo O succinato de desvenlafaxina (DVS) inibe seletivamente a recaptação da serotonina e é aprovado para transtornos depressivos maiores. Esta pesquisa investigou a influência do DVS na modulação da monoamina cerebral e do estresse oxidativo em camundongos. O potencial antiepiléptico de DVS (10, 20 ou 30 mg / kg / i.p.) Em pentilenotetrazole (PTZ; 85 mg / kg) com i.p. via de administração, estricnina (STR; 75 mg / kg) com i.p. via, pilocarpina (400 mg / kg) com s.c. rota e convulsão induzida por MES de eletrochoque máximo em modelos de camundongos. As atividades de estresse oxidativo, ou seja, superóxido dismutase (SOD), glutationa (GSH) e peroxidação lipídica (LPO), bem como ácido gama-aminobutírico (GABA) nos cérebros de camundongos convulsivos induzidos por PTZ. O tratamento com DVS aumentou a latência para desenvolver crises e diminuiu a mortalidade em roedores contra convulsões induzidas por PTZ, STR e pilocarpina. Os resultados de siezures conduzidos por MES revelaram que o DVS reduziu significativamente a duração e a mortalidade da extensão tônica dos membros posteriores. Os níveis de cérebro, SOD, GSH e GABA aumentaram significativamente (P 0,01) e o LPO reduziu significativamente (P 0,01) após o tratamento com DVS. Além disso, o DVS não apresentou sinais de coordenação motora no teste do rotarod. Demonstramos o papel do DVS na gênese da convulsão em camundongos sob condição de controle e atenua o dano oxidativo induzido por PTZ.

In silico and in vivo neuropharmacological evaluation of two γ-amino acid isomers derived from 2,3-disubstituted benzofurans, as ligands of GluN1-GluN2A NMDA receptor.

The GABAergic and glutamatergic neurotransmission systems are involved in seizures and other disorders of the central nervous system (CNS). Benzofuran derivatives often serve as the core in drugs used to treat such neurological disorders. The aim of this study was to synthesize new γ-amino acids structurally related to GABA and derived from 2,3-disubstituted benzofurans, analyze in silico their potential toxicity, ADME properties, and affinity for the GluN1-GluN2A NMDA receptor, and evaluate their potential activity and neuronal mechanisms in a murine model of pentylenetetrazol (PTZ)- and 4-aminopyridine (4-AP)-induced seizures. The in silico analysis evidenced a low risk of toxicity for the test compounds as well as the probability that they can cross the blood-brain barrier (BBB) to reach their targets in the CNS. According to docking simulations, these compounds bind at the active site of the NMDA glutamate receptor with high affinity. The in vivo assays demonstrated that 4 protects against 4-AP-induced seizure episodes, suggesting negative allosteric modulation (NAMs) at the glutamatergic NMDA receptor. Contrarily, 3 (the regioisomer of 4) and its racemic derivatives (cis-2,3-dihydrobenzofurans) were previously described to exacerbate such episodes, pointing to their positive allosteric modulation (PAMs) of the same receptor.

Pentylenetetrazol-induced seizures in adult rats are associated with plastic changes to the dendritic spines on hippocampal CA1 pyramidal neurons.

Epilepsy is a chronic neurobehavioral disorder whereby an imbalance between neurochemical excitation and inhibition at the synaptic level provokes seizures. Various experimental models have been used to study epilepsy, including that based on acute or chronic administration of Pentylenetetrazol (PTZ). In this study, a single PTZ dose (60 mg/kg) was administered to adult male rats and 30 min later, various neurobiological parameters were studied related to the transmission and modulation of excitatory impulses in pyramidal neurons of the hippocampal CA1 field. Rats experienced generalized seizures 1-3 min after PTZ administration, accompanied by elevated levels of Synaptophysin and Glutaminase. This response suggests presynaptic glutamate release is exacerbated to toxic levels, which eventually provokes neuronal death as witnessed by the higher levels of Caspase-3, TUNEL and GFAP. Similarly, the increase in PSD-95 suggests that viable dendritic spines are functional. Indeed, the increase in stubby and wide spines is likely related to de novo spinogenesis, and the regulation of neuronal excitability, which could represent a plastic response to the synaptic over-excitation. Furthermore, the increase in mushroom spines could be associated with the storage of cognitive information and the potentiation of thin spines until they are transformed into mushroom spines. However, the reduction in BDNF suggests that the activity of these spines would be down-regulated, may in part be responsible for the cognitive decline related to hippocampal function in patients with epilepsy.

Status Epilepticus Increases Cell Proliferation and Neurogenesis in the Developing Rat Cerebellum.

Status epilepticus (SE) promotes neuronal proliferation and differentiation in the adult and developing rodent hippocampus. However, the effect of SE on other neurogenic brain regions such as the cerebellum has been less explored. To determine whether SE induced by pentylentetrazole (PTZ-SE) and lithium-pilocarpine (Li-Pilo-SE) increases cell proliferation and neurogenesis in the developing rat cerebellum. SE was induced in 14-day-old (P14) Wistar rat pups (both sexes). One hour after SE and the following day rats were injected intraperitoneally with 5-bromo-2'-deoxyuridine (BrdU, 50 mg/kg). Seven days after SE, immunohistochemistry was performed to detect BrdU-positive (BrdU+) cells or BrdU/NeuN+ cells in the cerebellar vermis. SE induced by PTZ or Li-Pilo statistically significant increased the number of cerebellar BrdU+ cells when compared with the control group (58% and 40%, respectively); maximal cell proliferation occurred in lobules II, III, VIb, VIc, VIII, IXa, and IXb of PTZ-SE group and II, V, VIc, VII, and X of Li-Pilo-SE group. An increased number of BrdU/NeuN+ cells was detected in lobules V (17 ± 1.9), VIc (25.8 ± 2.7), and VII (26.2 ± 3.4) after Li-Pilo-SE compared to their control group (9.8 ± 1.7, 12.8 ± 2.8, and 11 ± 1.7, respectively), while the number of BrdU/NeuN+ cells remained the same after PTZ-induced SE or control conditions. SE induced in the developing rat by different experimental models increases cell proliferation in the granular layer of the cerebellar vermis, but only SE of limbic seizures increases neurogenesis in specific cerebellar lobes.

Physical exercise during pregnancy minimizes PTZ-induced behavioral manifestations in prenatally stressed offspring.

Stress during gestation has been shown to affect susceptibility and intensity of seizures in offspring. Environmental stimuli, such as maternal physical exercise, have shown to be beneficial for brain development. Although studies have demonstrated the deleterious influence of stress during pregnancy on seizure manifestation in offspring, very little is known on how to minimize these effects. This study verified whether physical exercise during the pregnancy associated with prenatal stress minimizes seizure susceptibility in offspring at the beginning of postnatal development. Pregnant rats and male pups were divided into the following groups: control, stress, stress/forced exercise, and stress/voluntary exercise. Behavioral manifestations were analyzed after injection of pentylenetetrazol (PTZ; 45 and 60 mg/kg) at ages P15 and P25. Increased behavioral manifestations and seizure severity was observed in the stress group compared with the control group at both ages. At the dose of 45 mg/kg, offspring of stressed mothers who performed both physical exercise models showed an increase in latency for the first manifestation and decrease in the seizures severity at both ages compared with the mothers groups who were only stressed. Prenatal restraint stress potentiated PTZ-induced seizure behavior, and both forced and voluntary exercise during gestation attenuates the negative effects of PTZ-induced offspring.

MPMT-OX up-regulates GABAergic transmission and protects against seizure-like behavior in Caenorhabditis elegans.

The signal transmission in the nervous system operates through a sensitive balance between excitatory (E) inputs and inhibitory (I) responses. Imbalances in this system contribute to the development of pathologies such as seizures. In Caenorhabditis elegans, the locomotor circuit operates via the coordinated activity of cholinergic excitatory (E) and GABAergic inhibitory (I) transmission. Changes in E/I inputs can cause uncontrolled electrical discharges, mimicking the physiology of seizures. Molecules derived from 1,3,4-oxadiazole have been found to exhibit diverse biological activities, including anticonvulsant effect. In this work, we study the activity of the compound 2-[(4-methoxyphenylselenyl)methylthio]-5-phenyl-1,3,4-oxadiazole (MPMT-OX) in the GABAergic and cholinergic systems. We demonstrate that MPMT-OX reduced the locomotor activity of C. elegans with a normal balance between the E/I systems and increased the resistance to paralysis in worms exposed to pentylenetetrazol and aldicarb. MPMT-OX increased seizure resistance and assisted in the recovery of locomotor activity in worms with deletions in the genes unc-46, which regulates the transport of GABA into vesicles, and unc-49, which encodes the GABAA receptor. C. elegans with deletions in the unc-25 and unc-47 genes did not respond to treatment. Therefore, we suggest that the compound MPMT-OX upregulates GABAergic signaling in a manner dependent on the unc-25 gene, which is responsible for GABA synthesis, and unc-47, which encodes the vesicular GABA transporter.

Synthesis and Biological Evaluation of Novel 2,3-disubstituted Benzofuran Analogues of GABA as Neurotropic Agents.

BACKGROUND: Benzofurans are heterocyclic compounds with neurotropic activity. Some have been developed for the treatment of acute and degenerative neuronal injuries. OBJECTIVE: The study aimed to evaluate the in silico binding of some promising benzofurans on the GABA receptors, and the in vivo neurotropic activity of benzofuran analogues (BZF 6-10) of gamma-aminobutyric acid (GABA) on a seizure model. METHODS: The ligands with the best physicochemical attributes were docked on two GABA receptors (the alpha-1 subunit of GABAA-R and GBR1 subunit of GABAB-R). Selected benzofuran derivatives were synthesized by a multistep procedure and characterized. To examine the neurotropic effects, mice were pretreated with different concentrations of the compounds prior to PTZ- or 4- AP-induced seizures. We assessed acute toxicity, motor behavior, and the effects on seizures. RESULTS: The tested ligands that complied with Lipinski's rule of five were tested in silico with GABAA-R (ΔG = -5.51 to -5.84 kcal/mol) at the allosteric site for benzodiazepines. They bound to a similar cluster of residues as the reference compound (gaboxadol, ΔG = -5.51 kcal/mol). Synthesis was achieved with good overall yields (42-9.7%). Two compounds were selected for biological tests (BZF-7 and rac-BZF-10) on a mouse model of seizures, induced by pentylenetetrazol (PTZ) or 4-aminopyridine (4-AP). PTZ-induced seizures are associated with GABA receptors, and those 4-AP-induced with the blockage of the delayed rectifier-type potassium channel, which promotes the release of the NMDA-sensitive glutamatergic ionotropic receptor and other neurotransmitters. The biological assays demonstrated that BZF-7 and rac-BZF-10 do not protect against seizures. Indeed, BZF-7 increased the number of PTZ-induced seizures and decreased latency time. The 4-AP model apparently showed a potentiation of seizure effects after administration of the BZF-analogues, evidenced by the incidence and severity of the seizures and reduced latency time. CONCLUSION: The results suggest that the test compounds are GABAergic antagonists with stimulatory activity on the CNS.

1-triacontanol cerotate isolated from Marsilea quadrifolia Linn. safeguards hippocampal CA3 neurons and augments special memory deficit in chronic epileptic rats / Cerotato de 1-triacontanol aislado de Marsilea quadrifolia Linn. protege las neuronas CA3 del hipocampo y mejora el déficit de memoria especial en ratas epilépticas crónicas

SUMMARY: Currently many people with epilepsy do not have seizure control even with the best available medications. Moreover various antiepileptics have adverse cognitive impact with other side effect. Thus, need for new antiepileptic drugs still remains challenge. However, many of the natural components have antiepileptic action and this fact remains scientifically unexplored. This study was designed to check the behavioral and neuro-pathological outcome of 1-Triacontanol cerotate (1TAC), isolated from Marsilea quadrifolia Linn. (MQ) on chronic Pentylenetetrazol (PTZ) kindling model of epilepsy in rats. Two-month-old adult male Wistar rats (n=60) were randomly divided into six groups; Group I (Cage Control), II (Vehicle Control), III (Positive Control), IV (Standard drug treated), V (1TAC: 40 mg/kg) & VI (1TAC: 80 mg/kg). To induce kindling a 35 mg/kg dose of PTZ was injected i.p. in every 48 hrs for 30 days in Group III to VI. Spatial memory performance was tested using Morris water maze, following which brains were further processed for histopathological investigations. Interestingly, 1TAC was able to minimize the loss of pyramidal cells in hippocampal CA3 region. These cellular changes were behaviorally responded as improved special learning and memory, a better spatial navigation and object place configuration. The current study strongly implicates that 1TAC from MQ has potent neuroprotective role and augments special memory deficit in chronic epileptic rats. The isolated component which attenuates spatial memory performance could be beneficial outcome to retain cognitive blunting in chronic epilepsy.

RESUMEN: Actualmente, muchas personas con epilepsia no cuentan con un control adecuado de las convulsiones, incluso con los mejores medicamentos disponibles. Además, varios antiepilépticos tienen un impacto cognitivo adverso además de efectos secundarios. Por lo tanto, la necesidad de nuevos fármacos antiepilépticos sigue siendo un desafío. Sin embargo, muchos de los componentes naturales tienen acción antiepiléptica y este hecho permanece científicamente inexplorado. Este estudio se diseñó para verificar el resultado conductual y neuro-patológico del cerotato de 1-triacontanol (1TAC), aislado de Marsilea quadrifolia Linn. (MQ) en el modelo de epilepsia en ratas del pentilenetetrazol (PTZ) crónico (PTZ). Ratas Wistar adultas de dos meses de edad (n = 60) se dividieron aleatoriamente en seis grupos; Grupo I (Control de jaula), II (Control de vehículo), III (Control positivo), IV (Medicamento estándar de tratamiento), V (1TAC: 40 mg / kg) y VI (1TAC: 80 mg / kg). Para inducir la inflamación se inyectó una dosis de 35 mg / kg de PTZ i.p. en cada 48 horas durante 30 días en los grupos III a VI. El rendimiento de la memoria espacial se probó utilizando el laberinto de agua de Morris, después de lo cual se procesaron los cerebros para investigaciones histopatológicas. Curiosamente, 1TAC pudo minimizar la pérdida de células piramidales en la región CA3 del hipocampo. Estos cambios celulares respondieron de manera conductual como una mejora del aprendizaje especial y la memoria, una mejor navegación espacial y la configuración del lugar del objeto. El estudio actual implica fuertemente que 1TAC de MQ tiene un potente papel neuroprotector y mejora el déficit de memoria especial en ratas epilépticas crónicas. El componente aislado que atenúa el rendimiento de la memoria espacial podría ser un resultado beneficioso para retener la reducción cognitiva en la epilepsia crónica.

Anticonvulsant effect of ethanolic extract of Cyperus articulatus L. leaves on pentylenetetrazol induced seizure in mice.

Cyperus articulatus (CA) rhizomes have demonstrated different properties on nervous system. However, the leaves still have not studied to treat epilepsy. The aim of this study was to determine the effect of CA ethanolic extract on pentylenetetrazol (PTZ) induced seizures in mice as well as measuring its antioxidant activity in vivo and in vitro. Mice were divided into five groups: (1) control (PTZ 80 mg/kg; i.p.), (2) PTZ-Diazepam (1 mg/kg; i.p.), (3-5) PTZ-CA 50, PTZ-CA 150 and PTZ-CA 300 (50, 150 and 300 mg/kg of CA extract, 30 min prior to each PTZ injection). The PTZ-CA 150 group showed lower seizure scores (P < 0.01), latency (P < 0.01), frequency (P < 0.01) and duration (P < 0.01) than control group. The antioxidant activity of CA extract scavenged DPPH radical showed IC 50 = 16.9 ± 0.1 µg/mL and TEAC = 2.28 ± 0.08, mmol trolox/g of extract, the content of gamma amino butyric acid (GABA) and malondialdehyde (MDA) were significantly high (P < 0.01) at dose of 150 mg/kg (82 ± 1.2 ng/g tissue; 1.0 ± 2.2 mol/g tissue, respectively). The present research demonstrated that CA extract possesses a potential effect to prevent PTZ induced seizures, antioxidant activity in addition to increase GABA levels.

Behavioral and Neurochemical Consequences of Pentylenetetrazol-Induced Kindling in Young and Middle-Aged Rats.

(1) Objectives: Epilepsy disorder is likely to increase with aging, leading to an increased incidence of comorbidities and mortality. In spite of that, there is a lack of information regarding this issue and little knowledge of cognitive and emotional responses in aging subjects following epileptogenesis. We investigated whether and how aging distress epilepsy-related behavioral and biochemical outcomes are associated with cognition and emotion. (2) Methods: Young and middle-aged Wistar rats (3 or 12 months old) were treated with pentylenetetrazol (PTZ, 35 mg/kg) and injected on alternated days for 20 (young rats) and 32 days (middle-aged rats). Kindling was reached after two consecutive stages 4 plus one stage 5 or 6 in Racine scale. Control and kindled rats were evaluated in the elevated plus-maze (EPM) and object-recognition tests and their hippocampus was collected 24 h later for mitogen-activated protein kinases (MAPK) dosage. (3) Results: Middle-aged rats presented a higher resistance to develop kindling, with a decrease in the seizure severity index observed following the 4th and 9th PTZ injections. Middle-aged rats displayed an increased duration of the first myoclonic seizure and an increased latency to the first generalized seizure when compared to younger rats. The induction of kindling did not impair the animals' performance (regardless of age) in the object-recognition task and the EPM test as well as it did not alter the hippocampal levels of MAPKs. (4) Significance: Our findings reveal that, despite age-related differences during epileptogenesis, middle-aged rats evaluated after kindling performed similarly during discriminative learning and emotional tasks in comparison to young animals, with no alteration of hippocampal MAPKs. Additional investigation must be carried out to explore the electrophysiological mechanisms underlying these responses, as well as the long-term effects displayed after kindling.

Cyclooxygenase-2 inhibitors differentially attenuate pentylenetetrazol-induced seizures and increase of pro- and anti-inflammatory cytokine levels in the cerebral cortex and hippocampus of mice.

Seizures increase prostaglandin and cytokine levels in the brain. However, it remains to be determined whether cyclooxygenase-2 (COX-2) derived metabolites play a role in seizure-induced cytokine increase in the brain and whether anticonvulsant activity is shared by all COX-2 inhibitors. In this study we investigated whether three different COX-2 inhibitors alter pentylenetetrazol (PTZ)-induced seizures and increase of interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interferon-γ (INF-γ), tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) levels in the hippocampus and cerebral cortex of mice. Adult male albino Swiss mice received nimesulide, celecoxib or etoricoxib (0.2, 2 or 20mg/kg in 0.1% carboxymethylcellulose (CMC) in 5% Tween 80, p.o.). Sixty minutes thereafter the animals were injected with PTZ (50mg/kg, i.p.) and the latency to myoclonic jerks and to generalized tonic-clonic seizures were recorded. Twenty minutes after PTZ injection animals were killed and cytokine levels were measured. PTZ increased cytokine levels in the cerebral cortex and hippocampus. While celecoxib and nimesulide attenuated PTZ -induced increase of proinflammatory cytokines in the cerebral cortex, etoricoxib did not. Nimesulide was the only COX-2 inhibitors that attenuated PTZ-induced seizures. This effect coincided with an increase of IL-10 levels in the cerebral cortex and hippocampus, constituting circumstantial evidence that IL-10 increase may be involved in the anticonvulsant effect of nimesulide.

Increased susceptibility to pentylenetetrazol following survival of cerebral malaria in mice.

Malaria is considered a neglected disease and public health problem, affecting >200 million people worldwide. In the present study we used the Plasmodium berghei ANKA (PbA) model of experimental cerebral malaria (CM) in C57BL/6 mice. After rescue from CM and parasite clearance, animals were submitted to a seizure susceptibility test (45 days after infection) using a low dose of pentylenetetrazol (PTZ, 30 mg/kg) and monitored with use of behavioral and electroencephalography (EEG) methods. Mice rescued from CM presented a reduced latency to myoclonic and tonic-clonic seizures and an increased duration of tonic-clonic seizures. In addition, quantitative analysis of EEG revealed a decrease in relative power at beta frequency band in PbA-infected animals after PTZ injection. Our results suggest that CM may lead to increased susceptibility to seizures in mice.

Metallothionein expression in the rat brain following KA and PTZ treatment.

Epilepsy is a neurological disorder that has been associated with oxidative stress therefore epilepsy models have been develop such as kainic acid and pentylenetetrazol are usually used to understanding of the molecular mechanisms of this disease. We examined the metallothionein expression in rat brains of treated with kainic acid and pentylenetetrazol. Increase in metallothionein and nitrotirosyne immunoreactivity of both seizures epilepsy models was observed. Moreover, we show a significant increase on levels of MT expression. These results suggest that the increase of metallothionein expression is related with kainic acid and pentylenetetrazol treatments as response to damage mediated by oxidative stress.

Cysteinyl leukotriene receptor (CysLT) antagonists decrease pentylenetetrazol-induced seizures and blood-brain barrier dysfunction.

Current evidence suggests that inflammation plays a role in the pathophysiology of seizures. In line with this view, selected pro-inflammatory arachidonic acid derivatives have been reported to facilitate seizures. Kainate-induced seizures are accompanied by leukotriene formation, and are reduced by inhibitors of LOX/COX pathway. Moreover, LTD4 receptor blockade and LTD4 synthesis inhibition suppress pentylenetetrazol (PTZ)-induced kindling and pilocarpine-induced recurrent seizures. Although there is convincing evidence supporting that blood-brain-barrier (BBB) dysfunction facilitates seizures, no study has investigated whether the anticonvulsant effect of montelukast is associated with its ability to maintain BBB integrity. In this study we investigated whether montelukast and other CysLT receptor antagonists decrease PTZ-induced seizures, as well as whether these antagonists preserve BBB during PTZ-induced seizures. Adult male albino Swiss mice were stereotaxically implanted with a cannula into the right lateral ventricle, and two electrodes were placed over the parietal cortex along with a ground lead positioned over the nasal sinus for electroencephalography (EEG) recording. The effects of montelukast (0.03 or 0.3 µmol/1 µL, i.c.v.), pranlukast (1 or 3 µmol/1 µL, i.c.v.), Bay u-9773 (0.3, 3 or 30 nmol/1 µL, i.c.v.), in the presence or absence of the agonist LTD4 (0.2, 2, 6 or 20 pmol/1 µL, i.c.v.), on PTZ (1.8 µmol/2 µL)-induced seizures and BBB permeability disruption were determined. The animals were injected with the antagonists, agonist or vehicle 30 min before PTZ, and monitored for additional 30 min for the appearance of seizures by electrographic and behavioral methods. BBB permeability was assessed by sodium fluorescein method and by confocal microscopy for CD45 and IgG immunoreactivity. Bay-u9973 (3 and 30 nmol), montelukast (0.03 and 0.3 µmol) and pranlukast (1 and 3 µmol), increased the latency to generalized seizures and decreased the mean amplitude of EEG recordings during seizures. LTD4 (0.2 and 2 pmol) reverted the anticonvulsant effect of montelukast (0.3 µmol). Montelukast (0.03 and 0.3 µmol) prevented PTZ-induced BBB disruption, an effect that was reversed by LTD4 at the dose of 6 pmol, but not at the doses 0.2 and 2 pmol. Moreover, the doses of LTD4 (0.2 and 2 pmol) that reverted the effect of montelukast on seizures did not alter montelukast-induced protection of BBB, dissociating BBB protection and anticonvulsant activity. Confocal microscopy analysis revealed that 1. PTZ increased the number of CD45+ and double-immunofluorescence staining for CD45 and IgG cells in the cerebral cortex, indicating BBB leakage with leukocyte infiltration; 2. while LTD4 (6 pmol) potentiated, montelukast decreased the effect of PTZ on leukocyte migration and BBB, assessed by double-immunofluorescence staining for CD45 and IgG cells in the cannulated hemisphere. Our data do not allow us ruling out that mechanisms unrelated and related to BBB protection may co-exist, resulting in decreased seizure susceptibility by montelukast. Notwithstanding, they suggest that CysLT1 receptors may be a suitable target for anticonvulsant development.

Anticonvulsant activity of alcoholic root extract of Cardiospermum halicacabum

The aim of the present study was to evaluate the anticonvulsant effects of alcoholic root extract of Cardiospermum halicacabum L., Sapindaceae (ARECH), on the various murine models of epilepsy. The root extract of the plant was administered p.o. to male swiss albino mice at doses of 30, 100 and 300 mg/kg before evaluation. The brain monoamine levels were determined after two days administration. ARECH at doses of 100 and 300 mg/kg significantly delayed the onset of clonus and tonus in pentylenetetrazol, isoniazid and picrotoxin-induced convulsions. Tonic hind limb extension was also decreased at doses of 100 and 300 mg/kg as compared to vehicle control in maximal electroshock model. No significant motor toxicity was observed even at a highest dose administered, i.e. 900 mg/kg. Brain monoamine analysis by HPLC revealed a significant increase in GABAergic activity in C+ (in cerebellum) and C- (except cerebellum). These results suggested that ARECH possesses a significant anticonvulsant activity with a low motor toxicity profile. This activity may be attributed to an increase in GABAergic activity.

El pretratamiento agudo y subcrónico con farmacos anticonvulsivantes modifica las crisis generalizadas inducidas por el pentilenetetrazol en el ratón / The acute and subchronic pretreatment with antiepileptic drugs modifies the pentylenetetrazol- induced generalized seizures in mice

Objetivo: El incremento en el contenido de GABA cerebral o la administración de un agente GABA-mimético se emplea como un tratamiento antiepiléptico eficaz. Sin embargo, se sugiere que el empleo de farmacos que alteran continuamente la transmisión sinoptica puede afectar al sistema nervioso. En el presente estudio se evaluaron los efectos del pretratamiento agudo (una administración) y subcrónico (administraciones diarias por 7 días) de diazepam (DZP; 10 mg/kg, ip), gabapentina (GBP, 100 mg/kg, vo) y vigabatrina (VGB, 500 mg/kg, vo) en las crisis generalizadas inducidas por pentilenetetrazol (PTZ, 80 mg/kg ip). Materiales y métodos: Ratones macho de la cepa taconic (20-25 g) recibieron tratamiento agudo y subcrónico de DZP, GBP o VGB y 24 h después de la última administración se aplicó PTZ. Se evaluaron las latencias a la primera crisis clónica, a la fase tónica así como la incidencia de muerte. Resultados: El pretratamiento agudo con DZP protegió 100 por ciento a los animales de los efectos del PTZ, mientras que su administración subcrónica redujo la latencia a la crisis clónica (21 por ciento; p<0.05), la fase tónica (27 por ciento, p<0.05) y muerte (37 por ciento, p<0.05). La aplicación aguda de VGB protegió 100 por ciento a los animales de los efectos del PTZ, mientras que su aplicación subcrónica aumentó la latencia a las crisis clónicas (32 por ciento, p<0.05), aunque facilitó la aparición de la crisis tónica (55 por ciento, p<0.05) y la muerte (58 por ciento, p<0.05). La administración aguda de GBP elevó la latencia a la crisis clónica (52 por ciento, p<0.05), mientras que su administración subcrónica no modificó el efecto producido por PTZ. Conclusiones: Estos resultados sugieren que el pretratamiento agudo y subcrónico de farmacos que incrementan la transmisión GABAérgica modifican diferencialmente la susceptibilidad a las crisis por PTZ y que su administración repetida puede facilitar la producción de crisis convulsivas.

Objetives: The increased GABA content or administration of a centrally active GABA-mimetic agent have been used as a efficacious anticonvulsant therapeutic approach. However, it has been suggested that the use of drugs that continually and noncontingently alter synaptic transmission could alter at the nervous system. The present study was carried out to investigate the effects of acute (one administration) and subchronic (7 daily administrations) treatments with Diazepam (DZP; 10 mg/kg, ip), Gabapentin (GBP, 100 mg/kg. vo) and Vigabatrin (VGB, 500 mg/kg, vo) on pentylenetetrazol-induced generalized seizures (PTZ, 80 mg/kg, ip). Materials and methods: Male Taconic mice (20-25 g) received acute or subchronic treatment with DZP, VGB or GBP and 24 h after the last administration, the effects of PTZ (latency to the clonus, forelimb extension and death incidence) were evaluated. Results: Acute DZP protected all animals (100 percent) to the convulsant effects of PTZ, whereas subchronic DZP decreased the latency to the clonic (21 percent; p<0.05), tonic (27 percent, p<0.05) and death (37 percent, p<0.05). The acute treatment with VGB protect all animals (100 percent) to the effects of PTZ, whereas its subcronic administration enhanced the latency to clonus (32 percent, p<0.05), but facilitated the appearance of tonic seizures (55 percent, p<0.05) and death (58 percent, p<0.05). The acute administration of GPB increased the latency to clonus (52 percent, p<0.05), whereas its subchronic treatment did not modify the PTZ-induced effects. Conclusions: The present results indicate that the acute pretreatment with drugs enhancing GABAergic transmission differently modifies the seizure susceptibility, and that the subchronic administration may facilitate the seizure activity.