Cortical expression of IL1-ß, Bcl-2, Caspase-3 and 9, SEMA-3a, NT-3 and P-glycoprotein as biological markers of intrinsic severity in drug-resistant temporal lobe epilepsy.

Mesial temporal lobe epilepsy (mTLE) is the most common epilepsy induced by previous cerebral injury, and one out of three mTLE patients develops drug resistance (DR). AIM: To assess the expression of Bcl-2, Caspase-3, Caspase-9, IL1-ß, SEMA-3a, NT-3 and P-glycoprotein in the temporal cortex and their relationship with the progression of mTLE-DR clinical features in patients with mTLE-DR. METHOD: Tissue samples from 17 patients were evaluated for protein expression by Western blot and the relationships of the evaluated proteins with the clinical features of the mTLE were assessed through hierarchical cluster analysis. RESULTS: The mTLE-DR group showed significantly higher P-glycoprotein, Bcl-2 and Caspase-9 levels ***p < 0.0001, ****p < 0.0001 and ***p < 0.0002, respectively, than the autopsy control group. Four patient clusters were identified: Clusters 1 and 3 showed relationships among the age of mTLE onset, duration of mTLE-DR, average number of epileptic seizures per week, number of previous antiepileptic drugs (AEDs) and increased expression of Caspase-3, Caspase-9, Neurotrophin-3 and Semaphorin-3a. Clusters 2 and 4 showed relationships among the mTLE onset age, current age, average number of epileptic seizures per week, number of previous AEDs and increased expression of IL1-ß, Bcl-2, P-glycoprotein, Caspase-3 and NT-3. CONCLUSION: The relationships among the clinical data the age of mTLE onset, DR duration, number of previous AEDs, and average number of seizures per week and the expression of proteins involved in neuronal death, neuroinflammation and aberrant connection formation, as which are biological markers in the cerebral temporal cortex, are important factors in the progression and severity of mTLE-DR and support the intrinsic severity hypothesis.

Activation of adenosine receptors modulates the efflux transporters in brain capillaries and restores the anticonvulsant effect of carbamazepine in carbamazepine resistant rats developed by window-pentylenetetrazole kindling.

Up-regulation of efflux transporters in brain capillaries may lead to the decreased therapeutic efficacy of antiepileptic drugs in patients with Drug Resistant Epilepsy. Adenosine receptor activation in brain capillaries can modulate blood-brain barrier permeability by decreasing the protein levels and function of efflux transporters. Therefore, we aimed to investigate whether the activation of adenosine receptors improves convulsions outcome in carbamazepine (CBZ) resistant animals and modulates the protein levels of efflux transporters (P-GP, MRP1, MRP2) in brain capillaries. We employed the window-pentylenetetrazol (PTZ) kindling model to develop CBZ resistant rats by CBZ administration during the post-kindling phase, and tested if these animals displayed subsequent resistance to other antiepileptic drugs. Crucially, we investigated if the administration of a broad-spectrum adenosine agonist (NECA) improves convulsions control in CBZ resistant rats. Of potential therapeutic relevance, in CBZ resistant rats NECA restored the anticonvulsant effect of CBZ. We also evaluated how the resistance to CBZ and the activation of adenosine receptors with NECA affect protein levels of efflux transporters in brain capillaries, as quantified by western blot. While CBZ resistance was associated with the up-regulation of both P-GP/MRP2 in brain capillaries, with the administration of NECA in CBZ resistant rats, we observed a decrease of P-GP and an increase of MRP2 levels, in brain capillaries. Since the activation of adenosine receptors improves the outcome of convulsions probably through the modulation of the efflux transporters protein levels in brain capillaries, adenosine agonists could be useful as an adjunct therapy for the control of Drug Resistant Epilepsy.

Allergic sensitization increases contractile responses to 5-HT in guinea pig aorta.

Epidemiological and clinical studies suggest that asthma is associated with adverse cardiovascular outcomes, but its mechanism is uncertain. 5-Hydroxytryptamine (5-HT) is a mediator involved in asthma and in cardiovascular functioning. Thus, in the present study, we explored whether allergic sensitization in guinea pigs modifies 5-HT-induced contractile responses and 5-HT2A receptor expression in thoracic aorta rings. We found that sensitization produced a significant increase of 100 microM 5-HT-induced contractions of aorta rings (~27 % greater contraction than in non-sensitized animals, p<0.05). Preincubation with 10 nM ketanserin (a 5-HT2A receptor antagonist) reduced by ~30 % (p=0.003) and ~36 % (p=0.005) the area under the curve of 5-HT-induced contractions in aortas from non-sensitized and sensitized animals, respectively. There were no differences between sensitized and non-sensitized animals with respect to mRNA (qPCR) and protein (Western blot) expression of 5-HT2A receptor in thoracic aortas. We concluded that in this guinea pig model of asthma, allergic sensitization is not confined to airways, but also affects arterial contractile responses to 5-HT; changes in the expression of the 5-HT2A receptor appear not to be involved in this phenomenon.

Magnolia officinalis reduces the long-term effects of the status epilepticus induced by kainic acid in immature rats.

During critical periods of neurodevelopment, the immature brain is susceptible to neuronal hyperexcitability, alterations such as hyperthermia, hypoxia, brain trauma or a preexisting neuroinflammatory condition can trigger, promote and prolong epileptiform activity and facilitate the development of epilepsy. The goal of the present study was to evaluate the long-term neuroprotective effects Magnolia officinalis extract, on a model of recurrent status epilepticus (SE) in immature rats. Sprague-Dawley rats were treated with kainic acid (KA) (3 mg/kg, dissolved in saline solution) beginning at day 10 P N every 24 h for five days (10 P N-14PN). Two experimental groups (KA) received two treatments for 10 days (14-24 P N): one group was treated with 300 mg/kg Magnolia Officinalis (MO) (KA-MO), and another was treated with 20 mg/kg of celecoxib (Clbx) (KA-Clbx) as a control drug. A SHAM control group at day 90 P N was established. Seizure susceptibility was analyzed through an after-discharge threshold (ADT) evaluation, and electroencephalographic activity was recorded. The results obtained from the ADT evaluation and the analysis of the electroencephalographic activity under basal conditions showed that the MO and Clbx treatments protected against epileptiform activity, and decreases long-term excitability. All rats in the KA-MO and KA-Clbx groups presented a phase I seizure on the Racine scale, corresponding to the shaking of a wet dog. In contrast, the KA group showed phase V convulsive activity on the Racine scale. Similarly, MO and Clbx exerted neuroprotective effects on hippocampal neurons and reduced gliosis in the same areas. Based on these results, early intervention with MO and Clbx treatments to prevent the inflammatory activity derived from SE in early phases of neurodevelopment exerts neuroprotective effects on epileptogenesis in adult stages.

Aromatase and estrogen receptor alpha mRNA expression as prognostic biomarkers in patients with astrocytomas.

Estrogens are oncogenic hormones at a high level in breast, prostate, endometrial and lung cancer. Estrogens are synthesized by aromatase which has been used as a biomarker both in breast and lung cancer. Estrogen biological activities are executed by their classic receptors (ERα and ERß). ERα has been described as a cancer promoter and ERß, as a possible tumor suppressor. Both receptors are present at low levels in primary multiforme glioblastoma (GBM). The GBM frequency is 50 % higher in men than in women. The GBM patient survival period ranges from 7 to 18 months. The purpose of this pilot study was to evaluate aromatase and estrogen receptor expression, as well as 17ß-estradiol concentration in astrocytoma patients biopsies to obtain a prognosis biomarker for these patients. We analyzed 36 biopsies of astrocytoma patients with a different grade (I-IV) of malignity. Aromatase and estrogen receptor mRNA expression were analyzed by semiquantitative RT-PCR, and the E2 levels, by ELISA. E2 concentration was higher in GBM, compared to grade II or III astrocytomas. The number of cells immunoreactive to aromatase and estrogen receptors decreased as the grade of tumor malignity increased. Aromatase mRNA expression was present in all biopsies, regardless of malignity grade or patient age or gender. The highest expression of aromatase mRNA in GBM patients was associated to the worst survival prognostic (6.28 months). In contrast lowest expression of ERα mRNA in astrocytoma patients had a worst prognosis. In conclusion, aromatase and ERα expression could be used as prognosis biomarkers for astrocytoma patients.

Deleterious versus neuroprotective effect of metabolic inhibition after traumatic spinal cord injury.

STUDY DESIGN: This work is an experimental and prospective study in adult, female, Long-Evans rats. OBJECTIVES: The aim of this study was to probe the effect of metabolic inhibition after an acute traumatic spinal cord injury (TSCI) using a standardized contusion model (NYU impactor) to know whether the metabolic inhibition is a 'secondary mechanism of injury' or a mechanism of protection. SETTING: All experimental procedures were carried out in the Mexico City. METHODS: Animals were divided into five groups: one sham and four with TSCI, including no treatment, rotenone (inhibitor of mitochondrial complex I), sodium azide (inhibitor of mitochondrial complex IV) and pyrophosphate of thiamine or non-degradable cocarboxylase as a metabolic reactivator. RESULTS: After TSCI, the metabolic inhibition with sodium azide treatment diminished the lipid peroxidation process (malondialdehyde levels by spectrophotometric procedures) and the damage to the spinal cord tissue (morphometric analysis), and increased the activity of creatine kinase and lactate dehydrogenase enzymes (P<0.05) (measured by spectrophotometric procedures 24 h after TSCI as well as after the functional recovery of the hind limb (evaluated weekly for 2 months by the BBB (Basso, Beattie and Bresnahan) scale)) when compared with the TSCI group without treatment. CONCLUSION: The results show that the partial and transitory inhibition of the aerobic metabolism after an acute TSCI could be a self-protection mechanism instead of being a 'secondary mechanism of injury'.

Hyperthermic seizures and hyperthermia in immature rats modify the subsequent pentylenetetrazole-induced seizures.

It has been described that febrile seizures during infancy increase risk of subsequent non-febrile seizures during the adulthood. However, latency period between febrile seizure and the onset of the first spontaneous seizure has not been evaluated. The present study was designed to investigate the susceptibility to subsequent seizures in immature rats that had experienced early-life hyperthermic seizures and before they achieved the adult age. The results were compared with those induced by hyperthermia alone. Pentylenetetrazol (PTZ) was applied 24h or 20 days after hyperthermic seizures or hyperthermia were induced in 10-day-old rats by a regulated stream of moderately heated air. One day after hyperthermic seizures or hyperthermia, animals demonstrated enhanced latency to the PTZ-induced myoclonic (88% and 53%, respectively), clonic (60% and 60%, respectively) and tonic seizures (233% and 659%, respectively). The incidence of myoclonic and clonic seizures was similar to that in control group (100%). However, hyperthermic seizures reduced (50%) the incidence of tonic seizures. Twenty days after hyperthermic seizures there was an augmented latency to tonic seizures (123%) and reduced incidence for all the PTZ-induced seizures (71% myoclonic; 71% clonic seizures; 57% tonic seizures) when compared with control group (100%). In contrast, hyperthermia enhanced only the latency to myoclonic (133%) and clonic seizures (659%). Our data indicate that hyperthermic seizures or hyperthermia induces a protective effect against PTZ-induced seizures during a latency period. A possible involvement of gamma-aminobutyric acid (GABA) system is discussed.

Muerte neuronal en la neocorteza de pacientes con epilepsia del lóbulo temporal resistente a fármacos / Neuronal death in the neocortex of drug resistant temporal lobe epilepsy patients

Introducción. La participación de mecanismos de muerteapoptótica en la epilepsia del lóbulo temporal resistente afármacos (ELTRF) es un aspecto muy discutido en la actualidad.Investigamos si existe pérdida neuronal y la inmunodeteccióna diferentes marcadores de muerte en tejido neocorticalen ocho pacientes con ELTRF y como tejido controlse evaluaron cinco neocortezas de sujetos fallecidos porcausas no neurológicas, pareados en edad y sexo.Métodos. La evaluación de la pérdida neuronal se realizópor medio de un estudio estereológico y por técnica inmunohistoquímicacon el marcador sinaptofisina. Se evaluóla inmunopositividad a diferentes marcadores apoptóticos(anexina V, caspasa 3 y 8, bcl-2 y p53), así como la detecciónde fragmentación del ácido desoxirribonucleico (ADN) (TUNEL),y se realizó en todos los casos un doble marcaje con sinaptofisina.Los resultados fueron evaluados por microscopiaconfocal y analizados por el programa Zeiss LSM 5 ImageBrowser, 2.80.1113 (Alemania).Resultados. Se observó una disminución estadísticamentesignificativa del número total de células (p<0,05), asícomo de las células sinaptofisina+ (p<0,01) en la neocorteza(capa IV) de los pacientes con ELTRF al ser comparadoscon el tejido control. No mostraron diferencias significativaslos marcadores apoptóticos bcl-2, p53, caspasa 3 y 8 paraninguna de las capas de neocorteza, mientras que sí resultóestadísticamente aumentado el número de células TUNEL+(p<0,05) y anexina V+ (p<0,05) en la capa IV neocortical delos pacientes.Conclusiones. Este grupo de evidencias hablan a favorde la existencia en la capa IV de neocorteza de una afectaciónen el número neuronal que se puede asociar a un procesode muerte apoptótica por una vía no dependiente de caspasas,sin que pueda ser descartada la muerte por necrosis (AU)

Introduction. Participation of apoptotic death mechanisms in drug resistant temporal lobe epilepsy (DRTLE) is currently under great debate. We have investigated if there is neuronal loss and the immunodetection to differentmarkers in neocortical tissue death in eigth patients with DRTLE. The neocortexes of five patients deceased due to non-neurological causes, paired in age and gender were evaluated as control tissue. Methods. The evaluation of neuronal loss was made by means of a stereological study and with immunohisto chemical techniques with the synaptophysin marker. Immunopositivity to different apoptotic markers (annexin V, caspase 3 and 8, bcl-2 and p53) and detection of deoxyribonucleic acid (DNA) fragmentation (TUNEL) wereanalyzed and double labeling with synaptophysin was performed in every case. The results were evaluated with confocal microscope and analyzed with the Zeiss LSM 5 Image Browser Program, 2.80.1113 (Germany). Results. A statistically significant decrease in the total number of cells (p < 0.05) and the synaptophysin cells+ (p<0.01) in the neocortex (layer IV) of the patients with DRTLE when compared with the control tissue was found. No significant differences were found in the apoptotic markers bcl-2, p53, caspase 3 and 8 for any of the neocortex layers while there was a statistically significantincrease in the number of TUNEL cells+ (p<0.05) and annexin V+ (p<0.05) in the neocortical layer IV of the patients. Conclusions. This group of evidence speaks in favor of the existence of an effect on the neuronal number in the neocortex layer IV that may be associated with non caspase dependent apoptotic death process, without beingable to rule out death by necrosis

[Pathological neocortical findings in patients with medication-resistant medial temporal lobe epilepsy submitted to surgery]. / Hallazgos patológicos neocorticales en pacientes con epilepsia del lóbulo temporal medial farmacorresistente sometidos a cirugía.

INTRODUCTION: The dual pathology consisting of hippocampal sclerosis plus focal cortical dysplasia (FCD) is often reported in patients with medication-resistant medial temporal lobe epilepsy (MTLE). AIMS: To determine the histopathological changes that take place in the neocortex of patients with medication-resistant MTLE submitted to surgery and to evaluate the relation between the histopathological changes, pathological background and the clinical course of patients who had received surgical treatment. MATERIALS AND METHODS: Tissue obtained by en bloc resection from the neocortex of 18 patients with MTLE refractory to medical treatment was processed histologically and a tailored temporal lobectomy was performed with electrocorticography. RESULTS: Dual pathology was diagnosed in 13 patients (72.2%). Imaging studies confirmed the existence of mesial sclerosis of the temporal in 100% of cases and there was no evidence of neocortical lesions. Histologically, 46.15% and 38.46% of the patients were diagnosed as belonging to FCD type 1a and FCD type 1b, respectively. Only one patient presented FCD type 2a. A statistically significant relation was found between the presence of dual pathology and the existence of an early precipitating injury (p = 0.04). One year after surgery, 72.7% (8/11) patients with dual pathology were classified as belonging to Engel class I. CONCLUSIONS: In patients with MTLE there are microscopic FCD-type alterations in the neocortex. There is an association between these alterations and the existence of an initial precipitating injury. Complete resection of the epileptogenic area, which is guaranteed by the lobectomy tailored by electrocorticography, allows patients to enjoy a favourable post-surgical progression one year after surgery.

[Neuronal death in the neocortex of drug resistant temporal lobe epilepsy patients]. / Muerte neuronal en la neocorteza de pacientes con epilepsia del lóbulo temporal resistente a fármacos.

Introduction. Participation of apoptotic death mechanisms in drug resistant temporal lobe epilepsy (DRTLE) is currently under great debate. We have investigated if there is neuronal loss and the immunodetection to different markers in neocortical tissue death in eigth patients with DRTLE. The neocortexes of five patients deceased due to non-neurological causes, paired in age and gender were evaluated as control tissue. Methods. The evaluation of neuronal loss was made by means of a stereological study and with immunohistochemical techniques with the synaptophysin marker. Immunopositivity to different apoptotic markers (annexin V, caspase 3 and 8, bcl-2 and p53) and detection of deoxyribonucleic acid (DNA) fragmentation (TUNEL) were analyzed and double labeling with synaptophysin was performed in every case. The results were evaluated with confocal microscope and analyzed with the Zeiss LSM 5 Image Browser Program, 2.80.1113 (Germany). Results. A statistically significant decrease in the total number of cells (p < 0.05) and the synaptophysin cells+ (p<0.01) in the neocortex (layer IV) of the patients with DRTLE when compared with the control tissue was found. No significant differences were found in the apoptotic markers bcl-2, p53, caspase 3 and 8 for any of the neocortex layers while there was a statistically significant increase in the number of TUNEL cells+ (p<0.05) and annexin V+ (p<0.05) in the neocortical layer IV of the patients. Conclusions. This group of evidence speaks in favor of the existence of an effect on the neuronal number in the neocortex layer IV that may be associated with noncaspase dependent apoptotic death process, without being able to rule out death by necrosis. Key words: Drug resistant temporal lobe epilepsy. Apoptosis. Necrosis. Neuronal loss. Neurología 2008;23(9):555-565.

Hallazgos patológicos neocorticales en pacientes con epilepsia del lóbulo temporal medial farmacorresistente sometidos a cirugía / Pathological neocortical findings in patients with medication-resistant medial temporal lobe epilepsy submitted to surgery

La patología dual compuesta por esclerosis hipocampal y displasia cortical focal (DCF) se describecon frecuencia en pacientes con epilepsia del lóbulo temporal medial (ELTM) farmacorresistente. Objetivos. Determinar los cambios histopatológicos en la neocorteza de pacientes con ELTM farmacorresistente sometidos a cirugía y evaluar la relación entre los cambios histopatológicos, los antecedentes patológicos y la evolución clínica en los pacientes operados. Materialesy métodos. Se procesó histológicamente el tejido resecado en bloque (neocorteza) de 18 pacientes con ELTM refractaria a tratamiento médico, y se les realizó lobectomía temporal ajustada por electrocorticografía. Resultados. Se diagnóstico patología dual en 13 pacientes (72,2%). Los estudios imagenológicos confirmaron en el 100% de los casos la esclerosis mesialdel temporal y no existieron evidencias de lesión neocortical. Histológicamente, el 46,15% y el 38,46% de los pacientes fueron diagnosticados como DCF tipo 1a y DCF tipo 1b, respectivamente. Sólo un paciente presentó DCF tipo 2a. Se demostró una relación estadísticamente significativa entre la presencia de patología dual y la existencia de una daño precipitante inicial (p = 0,04). El 72,7% (8/11) de los pacientes con patología dual un año después de la cirugía se clasificó en la clase Ide Engel. Conclusiones. En los pacientes con ELTM existen alteraciones microscópicas en la neocorteza del tipo DCF. Estas alteraciones se asocian a la existencia de un daño precipitante inicial. La resección completa de la zona epileptogénica, garantizadapor la lobectomía ajustada por electrocorticografía, permite una buena evolución posquirúrgica un año después de la cirugía

The dual pathology consisting of hippocampal sclerosis plus focal cortical dysplasia (FCD) is oftenreported in patients with medication-resistant medial temporal lobe epilepsy (MTLE). Aims. To determine the histopathological changes that take place in the neocortex of patients with medication-resistant MTLE submitted to surgery and to evaluate the relation between the histopathological changes, pathological background and the clinical course of patients whohad received surgical treatment. Materials and methods. Tissue obtained by en bloc resection from the neocortex of 18 patients with MTLE refractory to medical treatment was processed histologically and a tailored temporal lobectomy was performed with electrocorticography. Results. Dual pathology was diagnosed in 13 patients (72.2%). Imaging studies confirmed the existenceof mesial sclerosis of the temporal in 100% of cases and there was no evidence of neocortical lesions. Histologically, 46.15% and 38.46% of the patients were diagnosed as belonging to FCD type 1a and FCD type 1b, respectively. Only one patient presented FCD type 2a. A statistically significant relation was found between the presence of dual pathology and the existenceof an early precipitating injury (p = 0.04). One year after surgery, 72.7% (8/11) patients with dual pathology were classified as belonging to Engel class I. Conclusions. In patients with MTLE there are microscopic FCD-type alterations in the neocortex.There is an association between these alterations and the existence of an initial precipitating injury. Complete resection of the epileptogenic area, which is guaranteed by the lobectomy tailored by electrocorticography, allows patients to enjoy a favourable post-surgical progression one year after surgery

Hallazgos patológicos neocorticales en pacientes con epilepsia del lóbulo temporal medial farmacorresistente sometidos a cirugía / Pathological neocortical findings in patients with medication-resistant medial temporal lobe epilepsy submitted to surgery

Introducción. La patología dual compuesta por esclerosis hipocampal y displasia cortical focal (DCF) se describecon frecuencia en pacientes con epilepsia del lóbulo temporal medial (ELTM) farmacorresistente. Objetivos. Determinar los cambios histopatológicos en la neocorteza de pacientes con ELTM farmacorresistente sometidos a cirugía y evaluar la relación entre los cambios histopatológicos, los antecedentes patológicos y la evolución clínica en los pacientes operados. Materialesy métodos. Se procesó histológicamente el tejido resecado en bloque (neocorteza) de 18 pacientes con ELTM refractaria a tratamiento médico, y se les realizó lobectomía temporal ajustada por electrocorticografía. Resultados. Se diagnóstico patología dual en 13 pacientes (72,2por ciento). Los estudios imagenológicos confirmaron en el 100por ciento de los casos la esclerosis mesial del temporal y no existieron evidencias de lesión neocortical. Histológicamente, el 46,15 por ciento y el 38,46 por ciento de los pacientesfueron diagnosticados como DCF tipo 1a y DCF tipo 1b, respectivamente. Sólo un paciente presentó DCF tipo 2a. Se demostró una relación estadísticamente significativa entre la presencia de patología dual y la existencia de una daño precipitante inicial (p = 0,04). El 72,7por ciento (8/11) de los pacientes con patología dual un año después de la cirugía se clasificó en la clase Ide Engel. Conclusiones. En los pacientes con ELTM existen alteraciones microscópicas en la neocorteza del tipo DCF. Estas alteraciones se asocian a la existencia de un daño precipitante inicial. La resección completa de la zona epileptogénica, garantizada por la lobectomía ajustada por electrocorticografía, permite una buena evolución posquirúrgica un año después de la cirugía(AU)

INTRODUCTION: The dual pathology consisting of hippocampal sclerosis plus focal cortical dysplasia (FCD) is often reported in patients with medication-resistant medial temporal lobe epilepsy (MTLE). AIMS: To determine the histopathological changes that take place in the neocortex of patients with medication-resistant MTLE submitted to surgery and to evaluate the relation between the histopathological changes, pathological background and the clinical course of patients who had received surgical treatment. MATERIALS AND METHODS: Tissue obtained by en bloc resection from the neocortex of 18 patients with MTLE refractory to medical treatment was processed histologically and a tailored temporal lobectomy was performed with electrocorticography. RESULTS: Dual pathology was diagnosed in 13 patients (72.2percent). Imaging studies confirmed the existence of mesial sclerosis of the temporal in 100 percent of cases and there was no evidence of neocortical lesions. Histologically, 46.15 percent and 38.46 percent of the patients were diagnosed as belonging to FCD type 1a and FCD type 1b, respectively. Only one patient presented FCD type 2a. A statistically significant relation was found between the presence of dual pathology and the existence of an early precipitating injury (p = 0.04). One year after surgery, 72.7percent (8/11) patients with dual pathology were classified as belonging to Engel class I. CONCLUSIONS: In patients with MTLE there are microscopic FCD-type alterations in the neocortex. There is an association between these alterations and the existence of an initial precipitating injury. Complete resection of the epileptogenic area, which is guaranteed by the lobectomy tailored by electrocorticography, allows patients to enjoy a favourable post-surgical progression one year after surgery(AU)

Hyperthermia-induced seizures modify the GABA(A) and benzodiazepine receptor binding in immature rat brain.

Effects of hyperthermia-induced seizures (HS) on GABA(A) and benzodiazepine (BDZ) receptor binding in immature rat brain were evaluated using in vitro autoradiography. HS were induced in 10-days-old rats by a regulated stream of moderately heated air directed 50 cm above the animals. Rats were killed 30 min, 24 h or 20 days after HS and their brains were used for in vitro autoradiography experiments to determine GABA(A) and BDZ receptor binding. GABA(A) binding was significantly enhanced in all brain areas evaluated 30 min after HS, an effect that endures 24 h and 20 days after seizures. Concerning BDZ receptor binding, a significant increase was detected in entorhinal and perirhinal cortices and decreased in basolateral amygdala 30 min following HS. One day after HS, animals demonstrated enhanced BDZ binding in the cingulate, frontal, posterior parietal, entorhinal, temporal and perirhinal cortices; striatum, accumbens, substantia nigra pars compacta and amygdala nuclei. Twenty days after HS enhanced BDZ binding was restricted in the cingulated, frontal, anterior and posterior parietal cortices, as well as in substantia nigra pars reticulata, whereas decreased values were found in accumbens nucleus and substantia nigra pars compacta. Our data indicate differential effects of HS in GABA(A) and BDZ binding in immature brain. HS-induced GABA(A) and BDZ changes are different from those previously described in experimental models of temporal lobe epilepsy in adult animals.

Neuronal damage and changes in the expression of muscarinic acetylcholine receptor subtypes in the neonatal rat cerebral cortical upon exposure to sparteine, a quinolizidine alkaloid.

Sparteine is a quinolizidine alkaloid (QA) produced by Lupine species that has generated much interest due to its anti-hypertensive, anti-pyretic, and anti-inflammatory properties. In the nervous system, sparteine has been shown to display anti-cholinergic and depressive activity, although how sparteine exerts its toxic effects in the brain remains unclear. We have addressed this issue by administering subcutaneous injections of sparteine (25 mg/kg of body weight) to rats on postnatal days 1 and 3, and then examining the expression of the muscarinic acetylcholine receptor (mAChR) subunits m1-m4 in the brains of the neonatal rats 14-60 days later. Administration of sparteine to neonatal rats caused neuronal damage in the cerebral motor cortex accompanied by transient changes in the expression of m1-m4 mAChR subunits as revealed by both RT-PCR and Western blotting. This effect could be prevented by pre-treatment with atropine (10 mg/kg) 1 h prior to the injection of sparteine, suggesting that the cytotoxic activity of sparteine is mediated through mAChRs.

Increased expression of gamma-aminobutyric acid transporter-1 in the forebrain of infant rats with corticotropin-releasing hormone-induced seizures but not in those with hyperthermia-induced seizures.

High affinity, gamma-aminobutyric acid (GABA) plasma membrane transporters (GATs) influence the availability of GABA, the main inhibitory neurotransmitter in the brain. Recent studies suggest a crucial role for GATs in maintaining levels of synaptic GABA in normal as well as abnormal (i.e., epileptic) adult brain. However, the role of GATs during development and specifically changes in their expression in response to developmental seizures are unknown. The present study examined GAT-1-immunolabeling in infant rats with two types of developmental seizures, one induced by corticotropin-releasing hormone (CRH) lasting about 2 h and the other by hyperthermia (a model of febrile seizures) lasting only 20 min. The number of GAT-1-immunoreactive (ir) neurons was increased in several forebrain regions 24 h after induction of seizures by CRH as compared to the control group. Increased numbers of detectable GAT-1-ir cell bodies were found in the hippocampal formation including the dentate gyrus and CA1, and in the neocortex, piriform cortex and amygdala. In contrast, hyperthermia-induced seizures did not cause significant changes in the number of detectable GAT-1-ir somata. The increase in GAT-1-ir somata in the CRH model and not in the hyperthermia model may reflect the difference in the duration of seizures. The brain regions where this increase occurs correlate with the occurrence of argyrophyllic neurons in the CRH model.

Neuronal differentiation of chromaffin cells in vitro, induced by extremely low frequency magnetic fields or nerve growth factor: a histological and ultrastructural comparative study.

The application of nerve growth factor (NGF) to primary adrenal medulla chromaffin cell cultures induces phenotypic changes characterized mainly by the presence of neurites. A similar effect has been seen when these cells are stimulated by extremely low frequency magnetic fields (ELFMF). In this study, newborn rat chromaffin cells were cultured and subjected to NGF or ELFMF in order to compare their histological and ultrastructural characteristics. Cells cultured in the presence of NGF developed cytoplasmic projections and their distal ends showed growth cones as well as filopodia. With scanning and transmission electron microscopy, an increased submembranous electron density was observed in the nuclei of cells as well as irregular, wavy neuritic projections with a moderate number of varicosities, as well as the prevalence of intermediate filaments among the cytoskeleton components. Cells stimulated with ELFMF presented straighter neuritic extensions with a greater number of varicosities. With the transmission electron microscope, numerous neurotubules were observed, both in the cell soma and in their neuritic extensions. In both groups, growth cones were clearly identified by their ultrastructural characteristics. The differences seen in the cytoskeleton of cells stimulated with NGF or ELFMF suggest differential stimulation mechanisms possibly determining the biochemical, electrophysiological, and morphological characteristics in both types of cell cultures.