RESUMO
Gating differences occur between the alpha-subunits of the bovine and rat clones of an amiloride-sensitive epithelial Na+ channel (ENaC). Deletion of the carboxy terminus of bovine alpha-ENaC (alpha-bENaC) at R567 converted the gating properties to that of rat alpha-ENaC (alpha-rENaC). The equivalent truncation in alpha-rENaC was without effect on the gating of the rat homologue. The addition of actin to ENaC channels composed of either alpha-rENaC or alpha-bENaC alone produced a twofold reduction in conductance and an increase in open probability. Neither alpha-rENaC (R613X) nor alpha-bENaC (R567X) was responsive to actin. Using a chimera consisting of alpha-rENaC1-615 and alpha-bENaC570-650, we examined several different carboxy-terminal truncation mutants plus and minus actin. When incorporated into planar bilayers, the gating pattern of this construct was identical to wild-type (wt) alpha-bENaC. Premature stop mutations proximal to E685X produced channels with gating patterns like alpha-rENaC. Actin had no effect on the E631X truncation, whereas more distal truncations all interacted with actin, as did wt alpha-bENaC. Key findings were confirmed using channels expressed in Xenopus oocytes and studied by cell-attached patch-clamp recording. Our results suggest that the site of actin regulation at the carboxy terminus of the chimera is located between residues 631 and 644.
Assuntos
Actinas/metabolismo , Ativação do Canal Iônico , Canais de Sódio/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Bovinos , Canais Epiteliais de Sódio , Bicamadas Lipídicas/química , Bicamadas Lipídicas/metabolismo , Dados de Sequência Molecular , Oócitos , Técnicas de Patch-Clamp , Estrutura Terciária de Proteína , Ratos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Alinhamento de Sequência , Deleção de Sequência , Canais de Sódio/química , Canais de Sódio/genética , Xenopus laevisRESUMO
Child abuse and neglect are often a child's first introduction to the violent society in which he lives. Combatting violence, including child abuse, requires a multifaceted approach to reinforce the value of a human life and the commitment to a nonviolent lifestyle. Combining a home, school, and community approach strengthens a community's ability to improve skills of parents, teachers, youth, and citizens. EPIC program is such an approach that can be tailored to meet local needs. It is available in 50 New Jersey communities with replication assistance provided by NJ-NCPCA.
Assuntos
Maus-Tratos Infantis/prevenção & controle , Serviços de Saúde Escolar , Criança , Pré-Escolar , Relações Comunidade-Instituição , Humanos , Lactente , Recém-Nascido , Relações Interprofissionais , New Jersey , Poder Familiar , Papel do Médico , Prevenção Primária/métodos , Fatores de RiscoRESUMO
The effect of a pharmacologic dose of estrogen on brain monoamine systems in the rat fetus was determined using a semiquantitative measure of histofluorescence. Pregnant rats received a subcutaneous injection of cottonseed oil alone or estradiol (E2) in cottonseed oil just before the monoamine systems began to develop. The fetuses were delivered abdominally and killed on day 22 of gestation. A study of four major monoamine areas of the brain with a glyoxilic acid preparation showed that intrauterine exposure to E2 has a significant effect on the monoamine organization of the fetal hypothalamus. No treatment effects were noted in the areas of locus coeruleus, substantia nigra and corpus striatum. The litter sizes of the E2-treated rats and the body weights of the fetuses were much lower than those of the control group. The effect of E2 on monoamine distribution in the fetal hypothalamus may explain the reported disturbances of reproductive function and sexual behavior seen after perinatal exposure to high doses of estrogen in humans.
Assuntos
Encéfalo/embriologia , Dopamina/metabolismo , Estradiol/análogos & derivados , Feto/efeitos dos fármacos , Norepinefrina/metabolismo , Animais , Encéfalo/metabolismo , Estradiol/farmacologia , Feminino , Masculino , Gravidez , Distribuição Aleatória , Ratos , Ratos Endogâmicos , Diferenciação Sexual/efeitos dos fármacosRESUMO
Human and animal studies suggest impaired central nervous system (CNS) development due to corticoid use in the perinatal period. In this study, hydrocortisone was given to pregnant rats and the development of the fetal dopamine (DA) and norepinephrine (NE) systems in the CNS was investigated. In the fetal rat brain DA and NE systems develop between days 12 and 17 of gestation. Hydrocortisone (HC), 57 mg/kg/day, or saline (SAL) was given intraperitoneally at day 12 or 15 of gestation. The offspring were studied at days 20 to 21 of gestation and days 12 to 13 in the neonatal period. Brain amine systems were visualized using a modified cryostat glyoxylic acid histofluorescence method, and DA and NE levels were determined in whole brains by means of a radioenzymatic assay. The visualized amine systems were evaluated semiquantitatively for distribution and fluorescence intensity without previous knowledge of the administered drug. The amine systems of the HC and SAL groups showed an equal maturation. In both groups cell bodies were demonstrable in areas A1 to A13 and axon terminals in all examined final regions. The distribution and the fluorescence intensity did not show consistent differences for the HC and SAL brains. The concentrations of DA and NE were similar in the offspring of the SAL- and HC-treated animals. The results indicate that HC given during pregnancy does not influence the proliferation of amine cell bodies or the arrival of axon terminals in the regions where the synapses form.
