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1.
Int J Mol Sci ; 23(6)2022 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-35328544

RESUMO

Zingerone (ZO), a nontoxic methoxyphenol, has been demonstrated to exert various important biological effects. However, its action on varying types of ionic currents and how they concert in neuronal cells remain incompletely understood. With the aid of patch clamp technology, we investigated the effects of ZO on the amplitude, gating, and hysteresis of plasmalemmal ionic currents from both pituitary tumor (GH3) cells and hippocampal (mHippoE-14) neurons. The exposure of the GH3 cells to ZO differentially diminished the peak and late components of the INa. Using a double ramp pulse, the amplitude of the INa(P) was measured, and the appearance of a hysteresis loop was observed. Moreover, ZO reversed the tefluthrin-mediated augmentation of the hysteretic strength of the INa(P) and led to a reduction in the ICa,L. As a double ramp pulse was applied, two types of voltage-dependent hysteresis loops were identified in the ICa,L, and the replacement with BaCl2-attenuated hysteresis of the ICa,L enhanced the ICa,L amplitude along with the current amplitude (i.e., the IBa). The hysteretic magnitude of the ICa,L activated by the double pulse was attenuated by ZO. The peak and late INa in the hippocampal mHippoE-14 neurons was also differentially inhibited by ZO. In addition to acting on the production of reactive oxygen species, ZO produced effects on multiple ionic currents demonstrated herein that, considered together, may significantly impact the functional activities of neuronal cells.


Assuntos
Neoplasias Hipofisárias , Sódio , Potenciais de Ação , Guaiacol/análogos & derivados , Humanos , Transporte de Íons , Neurônios , Neoplasias Hipofisárias/patologia , Sódio/farmacologia
2.
Int J Mol Sci ; 21(1)2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31877994

RESUMO

Gastrodigenin (HBA) and gastrodin (GAS) are phenolic ingredients found in Gastrodia elata Blume (GEB), a traditional Chinese herbal medicine. These compounds have been previously used to treat cognitive dysfunction, convulsion, and dizziness. However, at present, there is no available information regarding their potential ionic effects in electrically excitable cells. In the current study, the possible effects of HBA and GAS on different ionic currents in pituitary GH3 cells and hippocampal mHippoE-14 neurons were investigated using the patch-clamp technique. The addition of HBA or GAS resulted in the differential inhibition of the M-type K+ current (IK(M)) density in a concentration-dependent manner in GH3 cells. HBA resulted in a slowing of the activation time course of IK(M), while GAS elevated it. HBA also mildly suppressed the density of erg-mediated or the delayed-rectifier K+ current in GH3 cells. Neither GAS nor HBA (10 µM) modified the voltage-gated Na+ current density, although they suppressed the L-type Ca2+ current density at the same concentration. In hippocampal mHippoE-14 neurons, HBA was effective at inhibiting IK(M) density as well as slowing the activation time course. Taken together, the present study provided the first evidence that HBA or GAS could act on cellular mechanisms, and could therefore potentially have a functional influence in various neurologic disorders.


Assuntos
Álcoois Benzílicos/farmacologia , Glucosídeos/farmacologia , Hipocampo/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Neurônios/metabolismo , Hipófise/metabolismo , Potássio/metabolismo , Linhagem Celular Tumoral , Hipocampo/citologia , Humanos , Neurônios/citologia , Hipófise/citologia
3.
Biomolecules ; 9(10)2019 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-31652643

RESUMO

Perampanel (PER) is a selective blocker of AMPA receptors showing efficacy in treating various epileptic disorders including brain tumor-related epilepsy and also potential in treating motor neuron disease. However, besides its inhibition of AMPA-induced currents, whether PER has any other direct ionic effects in different types of neurons remains largely unknown. We investigated the effects of PER and related compounds on ionic currents in different types of cells, including hippocampal mHippoE-14 neurons, motor neuron-like NSC-34 cells and U87 glioma cells. We found that PER differentially and effectively suppressed the amplitude of voltage-gated Na+ currents (INa) in mHippoE-14 cells. The IC50 values required to inhibit peak and late INa were 4.12 and 0.78 µM, respectively. PER attenuated tefluthrin-induced increases in both amplitude and deactivating time constant of INa. Importantly, PER also inhibited the amplitude of M-type K+ currents (IK(M)) with an IC50 value of 0.92 µM. The suppression of IK(M) was attenuated by the addition of flupirtine or ZnCl2 but not by L-quisqualic acid or sorafenib. Meanwhile, in cell-attached configuration, PER (3 µM) decreased the activity of M-type K+ channels with no change in single-channel conductance but shifting the activation curve along the voltage axis in a rightward direction. Supportively, PER suppressed IK(M) in NSC-34 cells and INa in U87 glioma cells. The inhibitory effects of PER on both INa and IK(M), independent of its antagonistic effect on AMPA receptors, may be responsible for its wide-spectrum of effects observed in neurological clinical practice.


Assuntos
Canais de Potássio de Abertura Dependente da Tensão da Membrana/antagonistas & inibidores , Piridonas/farmacologia , Receptores de AMPA/antagonistas & inibidores , Canais de Sódio Disparados por Voltagem/metabolismo , Animais , Linhagem Celular , Humanos , Camundongos , Nitrilas , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , Receptores de AMPA/metabolismo
4.
Cell Physiol Biochem ; 50(1): 150-168, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30278465

RESUMO

BACKGROUND/AIMS: Immunological mechanisms can be triggered as a response to central nervous system insults and can lead to seizures. In this study an investigation was made to determine if glatiramer acetate (GA), an immunomodulator currently used in the treatment of multiple sclerosis, could protect rats from pilocarpine-induced seizures and chronic epilepsy. METHODS: Two groups of adult male Sprague-Dawley rats, experimental (GA) and control, were used in the study. The systemic IL-1α and IL-1ß levels at baseline were checked as well as status epilepticus (SE), and the spontaneous recurrent seizure (SRS) stage by enzyme-linked immunosorbent assay. The GA group was given GA (150 µg/kg, ip) and the control group was given a saline injection prior to pilocarpine-induced seizures. Seizure susceptibility, severity and mortality were evaluated, using Racine seizure classification and hippocampal damage was evaluated by Nissl staining. The GA group received GA (150 µg/kg/day, ip) daily after SE, and the chronic spontaneous seizures were evaluated by long-term video recording, and mossy fiber sprouting was evaluated by Timm staining. The IL-1α and IL-1ß levels were correlated with seizure activities. The TNF-α level in the hippocampus was determined at the SRS stage by immunohistochemistry. The effect of GA on ionic currents and action potentials (APs) in NG108-15 differentiated neurons was investigated using patch-clamp technology. RESULTS: It was found that latency to severe seizures was significantly longer in the GA (p < 0.01) group, which also had SE of shorter duration and less frequent SRS (p < 0.01). GA attenuated acute hippocampal neuron loss and chronic mossy fiber sprouting in the CA3 and the SRS-reduction correlated with the reduction of IL-1α, but not with IL-1ß or TNF-α levels. Mechanistically, GA reduced the peak amplitude of voltage-gated Na+ current (INa), with a negative shift in the inactivation curve of INa and reduced the amplitude of APs along with decreased firing of APs. CONCLUSION: GA might serve as a neuroexcitability modulator which attenuates pilocarpine-induced acute and chronic excitotoxicity. Sodium channel attenuation was partially independent of the immunomodulatory effect.


Assuntos
Acetato de Glatiramer/uso terapêutico , Convulsões/prevenção & controle , Estado Epiléptico/prevenção & controle , Potenciais de Ação/efeitos dos fármacos , Animais , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Modelos Animais de Doenças , Acetato de Glatiramer/farmacologia , Interleucina-1alfa/análise , Interleucina-1beta/análise , Masculino , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Técnicas de Patch-Clamp , Pilocarpina/toxicidade , Ratos , Ratos Sprague-Dawley , Convulsões/induzido quimicamente , Convulsões/patologia , Índice de Gravidade de Doença , Estado Epiléptico/induzido quimicamente , Estado Epiléptico/patologia , Fator de Necrose Tumoral alfa/análise
5.
J Cell Physiol ; 232(12): 3409-3421, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28075010

RESUMO

In this study, we examine whether an anti-inflammatory thiourea derivative, compound #326, actions on ion channels. The effects of compound #326 on Ca2+ -activated K+ channels were evaluated by patch-clamp recordings obtained in cell-attached, inside-out or whole-cell configuration. In pituitary GH3 cells, compound #326 increased the amplitude of Ca2+ -activated K+ currents (IK(Ca) ) with an EC50 value of 11.6 µM, which was reversed by verruculogen, but not tolbutamide or TRAM-34. Under inside-out configuration, a bath application of compound #326 raised the probability of large-conductance Ca2+ -activated K+ (BKCa ) channels. The activation curve of BKCa channels was shifted to less depolarised potential with no modification of the gating charge of the curve; consequently, the difference of free energy was reduced in the presence of this compound. Compound #326-stimulated activity of BKCa channels is explained by a shortening of mean closed time, despite its inability to alter single-channel conductance. Neither delayed-rectifier nor erg-mediated K+ currents was modified. Compound #326 decreased the peak amplitude of voltage-gated Na+ current with no clear change in the overall current-voltage relationship of this current. In HEK293T cells expressing α-hSlo, compound #326 enhanced BKCa channels effectively. Intriguingly, the inhibitory actions of compound #326 on interleukin 1ß in lipopolysaccharide-activated microglia were significantly reversed by verruculogen, whereas BKCa channel inhibitors suppressed the expressions of inducible nitric oxide synthase. The BKCa channels could be an important target for compound #326 if similar in vivo results occur, and the multi-functionality of BKCa channels in modulating microglial immunity merit further investigation.


Assuntos
Anti-Inflamatórios/farmacologia , Agonistas dos Canais de Cálcio/farmacologia , Sinalização do Cálcio/efeitos dos fármacos , Cálcio/metabolismo , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/agonistas , Tioureia/farmacologia , Animais , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Células HEK293 , Humanos , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Ativação do Canal Iônico/efeitos dos fármacos , Cinética , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/genética , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Lipopolissacarídeos/farmacologia , Potenciais da Membrana , Camundongos Endogâmicos BALB C , Microglia/efeitos dos fármacos , Microglia/metabolismo , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Neoplasias Hipofisárias/metabolismo , Ratos , Tioureia/análogos & derivados , Transfecção
6.
PLoS One ; 8(6): e65154, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23785408

RESUMO

Diabetes can exacerbate seizures and worsen seizure-related brain damage. In the present study, we aimed to determine whether the standard antiepileptic drug pregabalin (PGB) protects against pilocarpine-induced seizures and excitotoxicity in diabetes. Adult male Sprague-Dawley rats were divided into either a streptozotocin (STZ)-induced diabetes group or a normal saline (NS) group. Both groups were further divided into subgroups that were treated intravenously with either PGB (15 mg/kg) or a vehicle; all groups were treated with subcutaneous pilocarpine (60 mg/kg) to induce seizures. To evaluate spontaneous recurrent seizures (SRS), PGB-pretreated rats were fed rat chow containing oral PGB (450 mg) for 28 consecutive days; vehicle-pretreated rats were fed regular chow. SRS frequency was monitored for 2 weeks from post-status epilepticus day 15. We evaluated both acute neuronal loss and chronic mossy fiber sprouting in the CA3 area. In addition, we performed patch clamp recordings to study evoked excitatory postsynaptic currents (eEPSCs) in hippocampal CA1 neurons for both vehicle-treated rats with SRS. Finally, we used an RNA interference knockdown method for Kir6.2 in a hippocampal cell line to evaluate PGB's effects in the presence of high-dose ATP. We found that compared to vehicle-treated rats, PGB-treated rats showed less severe acute seizure activity, reduced acute neuronal loss, and chronic mossy fiber sprouting. In the vehicle-treated STZ rats, eEPSC amplitude was significantly lower after PGB administration, but glibenclamide reversed this effect. The RNA interference study confirmed that PGB could counteract the ATP-sensitive potassium channel (KATP)-closing effect of high-dose ATP. By opening KATP, PGB protects against neuronal excitotoxicity, and is therefore a potential antiepileptogenic in diabetes. These findings might help develop a clinical algorithm for treating patients with epilepsy and comorbid metabolic disorders.


Assuntos
Anticonvulsivantes/farmacologia , Neuropatias Diabéticas/metabolismo , Neuropatias Diabéticas/patologia , Convulsões/metabolismo , Convulsões/patologia , Ácido gama-Aminobutírico/análogos & derivados , Trifosfato de Adenosina/metabolismo , Animais , Anticonvulsivantes/administração & dosagem , Glicemia , Linhagem Celular , Neuropatias Diabéticas/induzido quimicamente , Neuropatias Diabéticas/tratamento farmacológico , Neuropatias Diabéticas/mortalidade , Modelos Animais de Doenças , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Glibureto/administração & dosagem , Glibureto/farmacologia , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Canais KATP/metabolismo , Masculino , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Pilocarpina/efeitos adversos , Canais de Potássio Corretores do Fluxo de Internalização/genética , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Pregabalina , Ratos , Convulsões/induzido quimicamente , Convulsões/tratamento farmacológico , Convulsões/mortalidade , Estreptozocina/efeitos adversos , Ácido gama-Aminobutírico/administração & dosagem , Ácido gama-Aminobutírico/farmacologia
7.
Pediatr Infect Dis J ; 32(9): 1010-6, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23538518

RESUMO

OBJECTIVES: Hyper IgM syndrome (HIGM), characterized by recurrent infections, low serum IgG and IgA, normal or elevated IgM, defective class switch recombination and somatic hypermutation, are heterogeneous disorders with at least 6 distinct molecular defects, including the CD40 ligand (CD40L) and the nuclear factor κB essential modulator (NEMO, also known as IKKγ) genes (both X-linked), the CD40, activation-induced cytidine deaminase (AICDA or AID), uracil-DNA glycosylase genes (autosomal recessive) and IκBα (IKBA) (autosomal dominant). Our objective was to determine the molecular basis and clinical features of Taiwanese patients with the HIGM phenotype. METHODS: Clinical manifestations and candidate genes were analyzed in a nationwide population-based study. RESULTS: Among 14 patients (12 unrelated families) since 2003, 10 patents were identified (8 families) with CD40L mutations, including 2 novel deletions of "A" nucleotide (Del 347A and Del 366A), both frameshift and stop at the 127th location; 1 novel AID deletion mutation lack of the 37thAsp and 38th Ser; 1 ataxia-telangiectasia mutation; and 1 deletion of chromosome 1q42. An adult-onset patient with mutant (Thr254Met)CD40L had approximately 30% detectable affinity and therefore less severity. Memory B cells decreased in patients with CD40L and activation-induced cytidine deaminase mutations. Three mortalities encompassed renal cell carcinoma in 1 patient with (Tyr169Asn)CD40L, pneumothorax in 1 with (Tyr140Stop)CD40L and pneumonia after chemotherapy in an ataxia-telangiectasia patient. One patient without detectable genetic defects but normal lymphocyte proliferation resembled the mild form of common variable immune deficiency phenotype. CONCLUSIONS: In contrast to those with AICDA mutation, small chromosome 1 q42 deletion and unknown genetic defect, the majority (10/14; 71.4%) with CD40L mutations except (Thr254Met) and an ataxia-telangiectasia patient had the severe form of HIGM phenotype.


Assuntos
Ligante de CD40/genética , Síndrome de Imunodeficiência com Hiper-IgM/genética , Síndrome de Imunodeficiência com Hiper-IgM/patologia , Mutação , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Deleção de Sequência , Taiwan
8.
J Clin Neurosci ; 19(6): 896-8, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22330692

RESUMO

We report a 16-year-old girl with suspected psychotic mania, who subsequently developed amnesia, catatonia, oro-lingual dyskinesia, consciousness disturbance, seizure and respiratory failure. Repeated studies of the cerebrospinal fluid (CSF), viral culture and serology, brain MRI, single photon emission CT scan, and autoimmune profiles were all normal. She was finally diagnosed with anti-N-methyl D-aspartate receptor (NMDAR) encephalitis based on the positive finding of NMDAR antibodies in CSF. Her abdominal CT scan showed no detectable malignancy and pulse steroid therapy failed to have any effect. After administration of intravenous immunoglobulin her consciousness improved gradually. Anti-NMDAR encephalitis, with a characteristic neuropsychiatric syndrome, predominantly affects females with an ovarian tumor and is frequently misdiagnosed as a psychiatric disorder. Immunotherapy and eradication of associated malignancy are the main treatment strategies. Early recognition and early intervention of the disease should improve the outcome.


Assuntos
Encefalite Antirreceptor de N-Metil-D-Aspartato/complicações , Transtorno Bipolar/etiologia , Adolescente , Encefalite Antirreceptor de N-Metil-D-Aspartato/diagnóstico , Antimaníacos/uso terapêutico , Transtorno Bipolar/diagnóstico , Transtorno Bipolar/tratamento farmacológico , Eletroencefalografia , Feminino , Humanos , Midazolam/uso terapêutico , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada por Raios X , Ácido Valproico/uso terapêutico
9.
Pediatr Neonatol ; 52(6): 361-4, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22192267

RESUMO

Anti-N-methyl-d-aspartate (NMDA) receptor encephalitis is a treatment-responsive encephalitis associated with anti-NMDA receptor antibodies, which bind to the NR1/NR2 heteromers of the NMDA receptors. It is a highly characteristic syndrome evolving in five stages: the prodromal phase (viral infection-like symptoms), psychotic phase, unresponsive phase, hyperkinetic phase, and gradual recovery phase. It has been considered as a paraneoplastic syndrome usually affecting childbearing-age female with ovarian tumors; however, recent reports suggest a much higher incidence of nonparaneoplastic cases in children. We report a 14-year-old girl with anti-NMDA receptor encephalitis without a detectable tumor who showed a nearly complete recovery after intensive immunotherapy.


Assuntos
Encefalite/imunologia , Adolescente , Ansiolíticos , Eletroencefalografia , Encefalite/diagnóstico , Feminino , Humanos , Hipnóticos e Sedativos/administração & dosagem , Imunoglobulinas Intravenosas/uso terapêutico , Fatores Imunológicos/uso terapêutico , Imunoterapia , Imageamento por Ressonância Magnética , Midazolam/administração & dosagem , Receptores de N-Metil-D-Aspartato/imunologia
10.
Epilepsia ; 47(2): 288-96, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16499752

RESUMO

PURPOSE: Perinatal hypoxia is an important cause of brain injury in the newborn and has consequences that are potentially devastating and life-long, such as an increased risk of epilepsy in later life. The postsynaptic density (PSD) is a cytoskeletal specialization involved in the anchoring of neurotransmitter receptors and in regulating the response of postsynaptic neurons to synaptic stimulation. The postsynaptic protein PSD-95 binds to the N-methyl-D-aspartate receptor (NMDAR) subunit, and hence activates cascades of NMDAR-mediated events, such as cyclic adenosine monophosphate (cAMP)-responsive element binding protein phosphorylation at serine-133 (pCREB(Serine-133)). Here we studied the effect of perinatal hypoxia on protein interactions involving PSD-95 and the NMDAR, as well as pCREB(Ser-133) expression at an age when the animals show increased seizure susceptibility. METHODS: Rats were assigned randomly to the control rats or the rats exposed to transient global hypoxia at postnatal day 10 (P10). At P45, some rats from both groups were treated with pentylenetetrazol (PTZ) intraperitoneally to test the seizure threshold, and others were studied for neuronal loss, pCREB(Serine-133), PSD-95, and NMDAR expressions in the midbrain, temporal cortex, and hippocampal CA1 subfield by using immunohistochemistry, co-immunoprecipitation, and immunoblotting techniques, respectively. RESULTS: The rats with prior exposure to perinatal hypoxia exhibited increased seizure susceptibility to PTZ, compared with the control rats. Associated with this long-term change in seizure susceptibility, selective neuronal loss was observed in the midbrain region while pCREB(Ser-133) expression was reduced in the midbrain, temporal cortex, and hippocampal CA1 subfield. Perinatal hypoxia led to a decrease in PSD-95 expression in the both midbrain and hippocampal CA1 subfield, with the exception of temporal cortex. Furthermore, the association between PSD-95 and NMDAR subunits (NR1, NR2A, and NR2B) in the hippocampal CA1 was also markedly altered by perinatal hypoxia. CONCLUSIONS: This study demonstrates that the decrease in several protein complexes that are essential components of the postsynaptic apparatus is associated with the observed increase in seizure susceptibility in adult rats with prior exposure to perinatal hypoxia. The results indicate that reductions in PSD-95 expression, PSD-95 binding of NMDAR subunits, and subsequent NMDAR-mediated CREB phosphorylation, particularly in hippocampal CA1, are long-term consequences of perinatal hypoxia and may, at least in part, contribute to perinatal hypoxia-induced reduction in seizure threshold.


Assuntos
Encéfalo/metabolismo , Hipóxia Encefálica/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Convulsões/etiologia , Convulsões/metabolismo , Animais , Animais Recém-Nascidos , AMP Cíclico/metabolismo , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Modelos Animais de Doenças , Suscetibilidade a Doenças , Proteína 4 Homóloga a Disks-Large , Hipocampo/metabolismo , Hipóxia Encefálica/complicações , Hipóxia Encefálica/fisiopatologia , Immunoblotting , Imuno-Histoquímica , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Proteínas de Membrana/fisiologia , Mesencéfalo/metabolismo , Pentilenotetrazol , Fosforilação , Ligação Proteica , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Receptores de N-Metil-D-Aspartato/fisiologia , Fatores de Risco , Convulsões/induzido quimicamente , Serina/metabolismo , Lobo Temporal/metabolismo
11.
Epilepsy Res ; 68(2): 123-36, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16316743

RESUMO

Emerging evidence indicates that early maternal care permanently modifies the activity of hypothalamic-pituitary-adrenal (HPA) axis and is a critical factor in determining the capacity of the brain to compensate for later encountered insults. The purpose of this study was to determine the role of corticosterone (CORT) in the detrimental effects of neonatal isolation (NI) on seizures. Rats were assigned randomly to the following five groups: (1) control (CONT) rats; (2) NI rats that underwent daily separation from their dams from postnatal day 2 (P2) to P9; (3) status epilepticus (SE) rats, induced by lithium-pilocarpine (Li-Pilo) model at P10; (4) NI plus SE (NIS) rats and (5) NISM rats, a subset of NIS rats receiving metyrapone (100 mg/kg), a CORT synthesis inhibitor, immediately after SE induction. At P10, plasma CORT levels were compared at baseline in CONT and NI rats and in response to Li-Pilo-induced SE among SE, NIS and NISM rats. We evaluated the spatial memory in the Morris water maze at P50 approximately 55, the expression of hippocampal cyclic adenosine monophosphate (cAMP)-responsive element-binding protein phosphorylation at serine-133 (pCREBSer-133) at P55, hippocampal neuronal damage at P80 and seizure threshold at P100. The isolated rats exhibited higher CORT release in response to SE than non-isolated rats, and the NIS rats had greater cognitive deficits and decreased seizure threshold compared to the CONT, NI and SE groups. By contrast, the NISM group, compared to the NIS group, showed a normal CORT response to SE and better spatial memory but no difference in seizure threshold. Compared to the CONT group, the hippocampal pCREBSer-133 level was significantly reduced in all experimental groups (NI, SE, NIS, NISM) with no differences between groups. All rats were free of spontaneous seizures later in life and had no discernible neuronal loss in the hippocampus. Results in this model demonstrate repetitive NI enhances response of plasma CORT to SE, and exacerbates the neurological consequences of neonatal SE. Amelioration of neurological sequelae following reduction of the SE-induced excessive rise in plasma CORT implicates CORT in the pathogenesis of NI increasing the vulnerability to seizures.


Assuntos
Comportamento Animal , Corticosterona/sangue , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Privação Materna , Isolamento Social/psicologia , Comportamento Espacial/fisiologia , Animais , Animais Recém-Nascidos , Comportamento Animal/fisiologia , Convulsivantes , Corticosterona/fisiologia , Inibidores Enzimáticos/farmacologia , Hipocampo/metabolismo , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Excitação Neurológica , Lítio , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Metirapona/farmacologia , Fosforilação , Pilocarpina , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Comportamento Espacial/efeitos dos fármacos , Estado Epiléptico/induzido quimicamente
12.
World J Surg ; 28(3): 283-7, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14961195

RESUMO

Children with end-stage liver disease have been found to have cognitive deficits. The aim of this study was to examine whether cholestatic jaundice causes spatial deficits in rats and if these cognitive deficits are reversed by biliary drainage. Rats were randomly divided into three groups. In the first group, the bile duct was ligated for 3 weeks (BDL group); in the second group, the proximal bile duct was ligated with a Broviac CV catheter for 2 weeks followed by a tube bilioduodenostomy (TBD group); in the third group, a sham operation was performed (SHAM group). All the surviving rats were assessed for spatial learning and memory (a major cognitive function in rats) by the Morris water maze task about 3 weeks after the first operation. Blood was aspirated by cardiocentesis and assayed for total bilirubin, albumin, ammonia, and hemoglobin levels on the day following the water maze task. During the four consecutive acquisition trial days of the Morris water maze, jaundiced rats (BDL group) had a significant longer latency to escape than the SHAM group ( p < 0.05). Rats that underwent biliary decompression for 1 week (TBD group) showed improved status of the spatial deficit, as they required less time to reach the escape platform, approaching the performance of the SHAM group. The BDL group had a significantly higher serum ammonia level, higher bilirubin level, and lower hemoglobin level than the other two groups. After biliary decompression for 1 week, the serum albumin concentration in the TBD group still did not return to the level of the SHAM group. The results of this study suggest that long-term cholestasis results in spatial memory deficits in rats that correlate with anemia and hyperbilirubinemia encephalopathy. Early biliary decompression of obstructive jaundice improves spatial memory deficits, possibly related to the recovery of the serum ammonia and hemoglobin levels.


Assuntos
Sistema Biliar/fisiopatologia , Icterícia Obstrutiva/complicações , Transtornos da Memória/etiologia , Comportamento Espacial , Análise de Variância , Animais , Descompressão Cirúrgica , Modelos Animais de Doenças , Icterícia Obstrutiva/psicologia , Masculino , Aprendizagem em Labirinto , Transtornos da Memória/diagnóstico , Probabilidade , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Valores de Referência , Fatores de Risco , Sensibilidade e Especificidade , Índice de Gravidade de Doença
13.
Epilepsia ; 43(10): 1141-8, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12366727

RESUMO

PURPOSE: Maternal deprivation is stressful for the neonate. The aim of this study was to investigate the short- and long-term effects of maternal separation on recurrent seizures in the developing brain. METHODS: Rats were divided into four groups according to whether the rat pups were treated with maternal deprivation from postnatal day 2 (P2) to P9 or neonatal seizures induced by intraperitoneal (i.p.) injection of pentylenetetrazol (PTZ) from P10 to P14. Rats in the control group received saline i.p. injection from P10 to P14; rats in the isolation group underwent daily separation from their dams from P2 to P9; rats in the PTZ-treated group were subjected to PTZ-induced recurrent seizures from P10 to P14; rats in the isolation plus PTZ-treated group were subjected to maternal deprivation from P2 to P7 followed by serial seizures from P10 to P14. In addition, subsets of rats at P15 were killed and the brains assessed for acute neuronal degeneration. Visual-spatial memory test using the Morris water maze task was performed at P80. After testing, the hippocampus was evaluated for histologic lesions and cyclic adenosine monophosphate (cAMP)-responsive element-binding protein phosphorylation at serine-133 (pCREBSer-133), an important transcription factor underlying learning and memory. RESULTS: All rats given PTZ developed recurrent seizures. After PTZ administration, rats with a history of maternal deprivation had more intense impairment than did rats with maternal deprivation and neonatal seizures than those without deprivation. Neuronal degeneration was most prominent in the rats exposed to maternal deprivation plus recurrent seizures. Rats receiving maternal deprivation or PTZ-induced recurrent seizures exhibited only spatial deficits, but no morphologic changes in the hippocampus. However, rats with maternal deprivation plus PTZ-induced recurrent seizures exhibited worse visual-spatial learning compared with rats with either isolation or PTZ-induced recurrent seizures alone. The levels of pCREBSer-133 may play a role in the decrease in the hippocampus from the rats subjected to maternal deprivation and/or PTZ-induced recurrent seizures, as compared with rats exposed to vehicle-control saline. These results indicate that repeated maternal deprivation can exacerbate long-term cognitive deficits resulting from neonatal seizures. In addition, impaired phosphorylation of CREBSer-133. CONCLUSIONS: Repeated maternal deprivation stress has synergistic effects with recurrent seizures in inducing neurologic damage in the developing brain.


Assuntos
Encéfalo/crescimento & desenvolvimento , Transtornos Cognitivos/fisiopatologia , Privação Materna , Proteínas Repressoras , Convulsões/induzido quimicamente , Convulsões/fisiopatologia , Estresse Psicológico/fisiopatologia , Animais , Animais Recém-Nascidos , Comportamento Animal/fisiologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Modulador de Elemento de Resposta do AMP Cíclico , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/análise , Proteínas de Ligação a DNA/análise , Modelos Animais de Doenças , Hipocampo/química , Hipocampo/patologia , Hipocampo/fisiologia , Masculino , Aprendizagem em Labirinto/fisiologia , Memória/fisiologia , Degeneração Neural/patologia , Degeneração Neural/fisiopatologia , Pentilenotetrazol/farmacologia , Ratos , Ratos Sprague-Dawley , Convulsões/patologia , Fatores de Transcrição/análise
14.
Epilepsy Res ; 49(3): 218-25, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-12076843

RESUMO

Adenosine is an endogenous modulator that has an inhibitory effect on neuronal activity. The aim of this work was to investigate the role of aminophylline, an adenosine receptor antagonist, on the long-term effects of status epilepticus (SE) in the developing brain. Four groups of rats at the postnatal age of 12 days were intraperitoneally administered with saline, aminophylline (50 mg/kg), lithium-pilocarpine (Li-PC) (3 mEq/kg-60 mg/kg), and Li-PC plus aminophylline, respectively. The four groups were tested for spatial memory using the Morris water maze task at P80 and motor performance by the Rotarod test at P100. The brains were then analyzed with cresyl violet stain for histological lesions and evaluated for mossy fiber sprouting with the Timm stain. At the acute stage, all rats subjected to Li-PC developed SE and no seizures were elicited in the saline-treated or aminophylline-treated rats. The seizure duration was longer in the Li-PC plus aminophylline group (346.9+/-32.7 min) as compared with that in the Li-PC group (265.2+/-9.8 min). The difference of mortality was not significant. Rats without seizures exhibited no motor imbalance, spatial deficits, or morphological changes. The rats with Li-PC-induced SE demonstrated spatial memory deficits without motor incoordination or morphological changes. However, the rats subjected to Li-PC plus aminophylline exhibited motor impairment and morphological changes, including neuronal cell loss in CA1 area and increased mossy fiber sprouting in CA3 area. In addition, the rats of Li-PC plus aminophylline had greater spatial memory deficits than that seen in rats with Li-PC. We concluded that an adenosine receptor antagonist, such as aminophylline, had synergistic effects on the SE-induced long-term deficit of cognition and motor performance in the developing brain. The present study may provide experimental evidence and lead to novel therapeutic interventions.


Assuntos
Envelhecimento/efeitos dos fármacos , Aminofilina/efeitos adversos , Comportamento Animal/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Estado Epiléptico/patologia , Envelhecimento/fisiologia , Animais , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Destreza Motora/efeitos dos fármacos , Destreza Motora/fisiologia , Neurônios/patologia , Ratos , Ratos Sprague-Dawley , Estado Epiléptico/induzido quimicamente , Estado Epiléptico/fisiopatologia
15.
Neurosci Lett ; 321(3): 137-40, 2002 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-11880191

RESUMO

Here, we investigated whether aminophylline, an adenosine receptor antagonist used usually as a treatment for premature apnea, had synergistic effects on status epilepticus in the developing brain. On postnatal day 14 (P14), four groups of rats intraperitoneally received saline, aminophylline, lithium--pilocarpine (Li-PC), and Li-PC plus aminophylline, respectively. Subsequently, the Morris water maze task was performed at P80. The brains were then analyzed with cresyl violet stain for histological lesions and evaluated for mossy fiber sprouting with the Timm stain. No seizures were elicited in the saline-treated or aminophylline-treated rats. Both the Li-PC-treated and aminophylline plus Li-PC-treated rats exhibited seizures and there was no significant difference in mortality between the two groups. More interestingly, as in adulthood (P80), aminophylline aggravated the spatial deficits and histological damages seen in Li-PC-treated rats. In summary, this present study suggests that the use of adenosine receptor antagonists, such as aminophylline, exacerbates seizure-induced damage in the developing brain.


Assuntos
Aminofilina/toxicidade , Transtornos Cognitivos/fisiopatologia , Hipocampo/crescimento & desenvolvimento , Degeneração Neural/fisiopatologia , Inibidores de Fosfodiesterase/toxicidade , Antagonistas de Receptores Purinérgicos P1 , Estado Epiléptico/fisiopatologia , Envelhecimento/efeitos dos fármacos , Envelhecimento/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/patologia , Cones de Crescimento/efeitos dos fármacos , Cones de Crescimento/patologia , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Compostos de Lítio/farmacologia , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Fibras Musgosas Hipocampais/efeitos dos fármacos , Fibras Musgosas Hipocampais/patologia , Agonistas Muscarínicos/farmacologia , Degeneração Neural/induzido quimicamente , Degeneração Neural/patologia , Plasticidade Neuronal/efeitos dos fármacos , Plasticidade Neuronal/fisiologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Pilocarpina/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores Purinérgicos P1/metabolismo , Convulsões/induzido quimicamente , Convulsões/patologia , Convulsões/fisiopatologia , Estado Epiléptico/induzido quimicamente , Estado Epiléptico/patologia
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