RESUMO
The brain's response to a direct immune challenge was examined by in situ hybridization histochemistry. Lipopolysaccharide (bacterial endotoxin) injected acutely into rat striatum induced mRNA expression for inhibitory factor kappaBalpha, interleukin (IL)-1beta, tumor necrosis factor-alpha, IL-6, IL-12 p35, inducible nitric oxide synthase, IL-1 receptor antagonist, and the type 1 IL-1 receptor. Expression patterns were evaluated at select time points ranging from 15 min to 3 days post-injection. Rats injected with vehicle alone were used to control for mechanical effects. Following lipopolysaccharide administration, a wave of mRNA induction within brain parenchyma radiated outward from the injection site, generally peaking in intensity at the 16-h time point. The individual profiles of cytokine mRNA induction patterns reveal that the brain's immune response to local inflammatory stimulation is quite elaborate and in many ways resembles the progression of cytokine induction customary of localized inflammation in peripheral tissues.
Assuntos
Corpo Estriado/imunologia , Citocinas/genética , Citocinas/imunologia , Proteínas I-kappa B , Transdução de Sinais/imunologia , Animais , Autorradiografia , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/imunologia , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/imunologia , Hibridização In Situ , Proteína Antagonista do Receptor de Interleucina 1 , Interleucina-1/genética , Interleucina-1/imunologia , Interleucina-12/genética , Interleucina-12/imunologia , Interleucina-6/genética , Interleucina-6/imunologia , Lipopolissacarídeos/farmacologia , Masculino , Microinjeções , Inibidor de NF-kappaB alfa , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase Tipo II , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de Interleucina-1/genética , Receptores de Interleucina-1/imunologia , Sialoglicoproteínas/genética , Sialoglicoproteínas/imunologia , Transcrição Gênica/imunologia , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologiaRESUMO
The brain's response to a direct immune challenge was examined by in situ hybridization histochemistry. Lipopolysaccharide (bacterial endotoxin) injected acutely into rat striatum induced mRNA expression for inhibitory factor kappaBalpha, interleukin (IL)-1beta, tumor necrosis factor-alpha, IL-6, IL-12 p35, inducible nitric oxide synthase, IL-1 receptor antagonist, and the type 1 IL-1 receptor. Expression patterns were evaluated at select time points ranging from 15 min to 3 days post-injection. Rats injected with vehicle alone were used to control for mechanical effects. Following lipopolysaccharide administration, a wave of mRNA induction within brain parenchyma radiated outward from the injection site, generally peaking in intensity at the 16-h time point. The individual profiles of cytokine mRNA induction patterns reveal that the brain's immune response to local inflammatory stimulation is quite elaborate and in many ways resembles the progression of cytokine induction customary of localized inflammation in peripheral tissues.
Assuntos
Corpo Estriado/fisiologia , Citocinas/genética , Sistema Imunitário/fisiologia , Lipopolissacarídeos/farmacologia , RNA Mensageiro/metabolismo , Transdução de Sinais/fisiologia , Animais , Proteínas I-kappa B/genética , Injeções , Proteína Antagonista do Receptor de Interleucina 1 , Masculino , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase Tipo II , Ratos , Ratos Sprague-Dawley , Receptores de Interleucina-1/genética , Sialoglicoproteínas/genética , Fatores de Tempo , Distribuição TecidualRESUMO
Although it is generally accepted that pro-inflammatory cytokines produced by cells of the central nervous system play important roles in the communication between the central nervous system and the immune system during sepsis, it is not clear whether these cytokines are produced in the brain under subseptic conditions. In this study, we used in situ hybridization to examine the mRNA expression of the pro-inflammatory cytokines IL-1beta and TNFalpha in the brains of rats 2 and 12 h after they were challenged by peripheral injections of lipopolysaccharide (LPS) ranging from 0.01 to 1000 microg/kg. Unlike septic doses of LPS (> 500 microg/kg), which induce global expression of pro-inflammatory cytokines in the brain, subseptic doses of LPS (0.01-10 microg/kg) induced IL-1beta and TNFalpha mRNA expression only in the choroid plexus, the circumventricular organs, and meninges. The expression of the cytokine-responsive immediate early gene I kappaB alpha was induced in the brain after doses of LPS as low as 0.1 microg/kg. I kappaB alpha mRNA expression was confined to sites where IL-1beta and TNFalpha were expressed. These results indicate that the induction and action of pro-inflammatory cytokines during subseptic infection occur at the blood-brain barrier and at circumventricular organs, which may be sites for elaboration of signal molecules that communicate peripheral immune status to the brain.
Assuntos
Encéfalo/imunologia , Encefalite/imunologia , Interleucina-1/genética , Lipopolissacarídeos/farmacologia , Fator de Necrose Tumoral alfa/genética , Animais , Autorradiografia , Encéfalo/enzimologia , Caspase 1/imunologia , Caspase 1/metabolismo , Encefalite/induzido quimicamente , Encefalite/metabolismo , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/imunologia , Injeções Intravenosas , Interleucina-1/imunologia , Masculino , Núcleo Hipotalâmico Paraventricular/química , Núcleo Hipotalâmico Paraventricular/enzimologia , Núcleo Hipotalâmico Paraventricular/imunologia , Proteínas Proto-Oncogênicas c-fos/genética , Proteínas Proto-Oncogênicas c-fos/imunologia , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores de Interleucina-1/antagonistas & inibidores , Receptores de Interleucina-1/imunologia , Núcleo Solitário/química , Núcleo Solitário/enzimologia , Núcleo Solitário/imunologia , Órgão Subfornical/química , Órgão Subfornical/enzimologia , Órgão Subfornical/imunologia , Fator de Necrose Tumoral alfa/imunologiaRESUMO
The suprachiasmatic nucleus (SCN) in the hypothalamus serves as the pacemaker for mammalian circadian rhythms. In a hamster brain slice preparation, the authors were able to record spontaneous activity from SCN cells for up to 4 days in vitro and verify a self-sustained rhythm in firing. The phase of this rhythm was altered by the concentration of glucose in the bathing medium, with time of peak firing advanced for a 20 mM glucose condition and slightly delayed for a 5 mM glucose condition, relative to 10 mM. The advancing effect of 20 mM glucose and the delaying effect of 5 mM glucose were not maintained during a 2nd day in vitro after changing the bathing medium back to 10 mM glucose, thus indicating the effect was not a permanent phase shift of the underlying oscillation. In experiments recording from cell-attached membrane patches on acutely dissociated hamster SCN neurons, exchanging the bathing medium from high (20 mM) to zero glucose increased potassium (K+)-selective channel activity. With inside-out membrane patches, the authors revealed the presence of a glybenclamide-sensitive K+ channel (190 pS) and a larger conductance (260 pS) Ca(2+)-dependent K+ channel that were both reversibly inhibited by ATP at the cytoplasmic surface. Furthermore, 1 mM tetraethylammonium chloride was demonstrated to advance peak firing time in the brain slice in a similar manner to a high concentration of glucose (20 mM). The authors interpret the result to imply that SCNs are sensitive to glucose, most probably via ATP modulation of K+ channel activity in these neurons. Tonic modulation of K+ channel activity appears to alter output of the pacemaker but does not reset the phase.
Assuntos
Glucose/farmacologia , Neurônios/efeitos dos fármacos , Núcleo Supraquiasmático/fisiologia , Trifosfato de Adenosina/metabolismo , Animais , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Cricetinae , Técnicas In Vitro , Masculino , Mesocricetus , Técnicas de Patch-Clamp , Canais de Potássio/efeitos dos fármacos , Canais de Potássio/metabolismo , Núcleo Supraquiasmático/citologia , Núcleo Supraquiasmático/efeitos dos fármacosRESUMO
We have encountered a case of apparent intoxication with primidone (Mysoline) in a patient with severe renal impairment. Of interest were high serum levels of phenylethyl-malondiamide (PEMA), a metabolite of primidone.
Assuntos
Malonatos/intoxicação , Feniletilmalonamida/intoxicação , Primidona/intoxicação , Adulto , Biotransformação , Feminino , Meia-Vida , Humanos , Feniletilmalonamida/sangue , Primidona/sangue , Primidona/uso terapêutico , Esclerose Tuberosa/sangue , Esclerose Tuberosa/tratamento farmacológicoRESUMO
We describe a method for measuring therapeutic and overdose levels of barbiturate, sedative, and anticonvulsant drugs in serum by gas-liquid chromatography (GLC). This method is a unique combination of techniques including a simple extraction, cochromatography of the specimen with authentic carrier drugs, and the use of multiple dissimilar gas chromatographic columns. In this way, a large number of drugs may be identified and quantitated without confusion.
