RESUMO
Neurofilaments subunits (NF-H, NF-M, NF-L) and glial fibrillary acidic protein (GFAP) were investigated in the hippocampus of rats after distinct periods of reperfusion (1 to 15 days) following 20 min of transient global forebrain ischemia in the rat. In vitro [14Ca]leucine incorporation was not altered until 48 h after the ischemic insult, however concentration of intermediate filament subunits significantly decreased in this period. Three days after the insult, leucine incorporation significantly increased while the concentration NF-H, NF-M, and NF-L were still diminished after 15 days of reperfusion. In vitro incorporation of 32P into NF-M and NF-L suffered immediately after ischemia, but returned to control values after two days of reperfusion. GFAP levels decreased immediately after ischemia but quickly recovered and significantly peaked from 7 to 10 days after the insult. These results suggest that transient ischemia followed by reperfusion causes proteolysis of intermediate filaments in the hippocampus, and the proteolysis could be facilitated by diminished phosphorylation levels of NF-M and NF-L.
Assuntos
Proteína Glial Fibrilar Ácida/biossíntese , Hipocampo/metabolismo , Ataque Isquêmico Transitório/metabolismo , Proteínas de Neurofilamentos/metabolismo , Animais , Radioisótopos de Carbono , Proteínas do Citoesqueleto/metabolismo , Cinética , Leucina/metabolismo , Radioisótopos de Fósforo , Técnica de Diluição de Radioisótopos , Ratos , Ratos Wistar , Reperfusão , Fatores de TempoAssuntos
Cardiomiopatia Hipertrófica , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Cardiomiopatia Hipertrófica/complicações , Cardiomiopatia Hipertrófica/diagnóstico , Cardiomiopatia Hipertrófica/genética , Cardiomiopatia Hipertrófica/fisiopatologia , Criança , Pré-Escolar , Morte Súbita Cardíaca/etiologia , Eletrocardiografia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-IdadeRESUMO
In this investigation we studied developmentally regulated endogenous protein kinase activity in cytoskeletal proteins in the cerebral cortex of rats and the effect of early malnutrition imposed on dams on the pattern of 32P incorporation into the cytoskeleton of pups. Our results indicated that in vitro incorporation was maximum in 7-day-old pups for both normal and malnourished groups, decreasing with development, and reaching minimum values in adult animals. However, 32P incorporation into NF-M and tubulin was significantly lower in 7-day-old malnourished pups than in normal pups.
Assuntos
Envelhecimento/metabolismo , Córtex Cerebral/metabolismo , Proteínas do Citoesqueleto/metabolismo , Distúrbios Nutricionais/metabolismo , Proteínas Quinases/metabolismo , Animais , Autorradiografia , Peso Corporal , Córtex Cerebral/anatomia & histologia , Córtex Cerebral/crescimento & desenvolvimento , Proteínas do Citoesqueleto/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Tamanho do Órgão , Fosfoproteínas/isolamento & purificação , Fosfoproteínas/metabolismo , Radioisótopos de Fósforo , Fosforilação , Ratos , Valores de ReferênciaRESUMO
Wistar rats were fed a normal protein (25% casein) or an isoenergetic low protein (8% casein) diet from the day of birth to weaning on day 21. Litters were killed at weaning and cerebral cortex was removed. Tubulin was prepared by centrifugation at 100,000 g, 4 degrees C, as described by Shelansky et al. [Proc. Natn. Acad. Sci. U.S.A. 70, 765-768 (1973)]. Cold-insoluble tubulin was recovered in the pellet (P1) fraction and cold-soluble tubulin in the supernatant (S1) fraction. Alpha and beta tubulin were quantified by electrophoretic and immunological methods in both fractions. Our results indicated that malnutrition enhanced the ratio of cold-insoluble-tubulin-to-cold-soluble-tubulin. Furthermore malnutrition induced an increased in vitro incorporation of 32P into both soluble and insoluble tubulins. Although tubulin phosphorylation has been related to tubulin stability properties, we cannot unequivocally ascribe the increased insoluble/soluble tubulin ratio with malnutrition to increased in vitro incorporation of 32P.
Assuntos
Trifosfato de Adenosina/metabolismo , Córtex Cerebral/metabolismo , Deficiência de Proteína/metabolismo , Tubulina (Proteína)/metabolismo , Animais , Temperatura Baixa , Focalização Isoelétrica , Fosforilação , Ratos , Ratos Wistar , SolubilidadeRESUMO
Wistar rats were fed a normal protein (25% casein) or an isoenergetic low protein (8% casein) diet from the day of giving birth until pups were weaned. Some litters were killed at weaning; others (both normal and malnourished animals) received the 25% protein diet until d 90 when they were killed. Intermediate filament (IF) preparations were obtained by extraction of the cerebral cortex with a high salt PBS solution containing 1% Triton X-100. The pellet contained the bulk of the cytoskeleton proteins from tissue, identified as the 150- and 68-kDa subunits of neurofilaments (NF-M and NF-L, respectively), the 66-kDa associated protein, the 57-kDa intermediate filament-like protein, and the 50-kDa glial fibrillary acidic protein. Intermediate filament-enriched fractions from control and malnourished rats at both d 21 and 90 were scanned following two-dimensional gel electrophoresis to determine the effects of postnatal malnutrition on the intermediate filament protein content. The results indicated that postnatal malnutrition imposed during the brain growth spurt period did not alter the expression of IF proteins of the cerebral cortex in 21-d-old rats, but increased the expression of NF-L and NF-M proteins in adult rats.