Home About us Contact
|
Home About us Contact | ||
|
|
||
Mature Nervous System (mature + nervous_system)
Selected AbstractsSPARC is expressed by macroglia and microglia in the developing and mature nervous systemDEVELOPMENTAL DYNAMICS, Issue 5 2008Adele J. Vincent Abstract SPARC (secreted protein, acidic and rich in cysteine) is a matricellular protein that is highly expressed during development, tissue remodeling, and repair. SPARC produced by olfactory ensheathing cells (OECs) can promote axon sprouting in vitro and in vivo. Here, we show that in the developing nervous system of the mouse, SPARC is expressed by radial glia, blood vessels, and other pial-derived structures during embryogenesis and postnatal development. The rostral migratory stream contains SPARC that becomes progressively restricted to the SVZ in adulthood. In the adult CNS, SPARC is enriched in specialized radial glial derivatives (Müller and Bergmann glia), microglia, and brainstem astrocytes. The peripheral glia, Schwann cells, and OECs express SPARC throughout development and in maturity, although it appears to be down-regulated with maturation. These data suggest that SPARC may be expressed by glia in a spatiotemporal manner consistent with a role in cell migration, neurogenesis, synaptic plasticity, and angiogenesis. Developmental Dynamics 237:1449-1462, 2008. © 2008 Wiley-Liss, Inc. [source] Diazepam Terminates Brief but Not Prolonged Seizures in Young, Naïve RatsEPILEPSIA, Issue 8 2003Howard P. Goodkin Summary: Purpose: Ample evidence exists from both clinical and animal studies that the success of benzodiazepine intervention during status epilepticus (SE) in the mature nervous system is inversely related to seizure duration. This relationship has not been well studied in the developing nervous system. Methods: The objective of this study was to investigate the relation of age and success of diazepam (DZP) treatment in the lithium-pilocarpine model of secondarily generalized seizure in the rat by using naïve rats of three age groups, roughly corresponding to the human ages of infancy (P15), adolescence (P20), and adult (P60). Results: In all age groups, the dosage of DZP that stopped the seizures at 5 min was not effective in terminating seizures at 60 min. This decline in efficacy was present as early as 15 min after seizure onset. Conclusions: These findings demonstrate that the inverse relation between the success of benzodiazepine intervention and seizure duration is observed in young as well as in adult rats and provide further evidence that intervention for SE should commence early. [source] A putative role for cell cycle-related proteins in microtubule-based neuroplasticityEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2009Stefanie Schmetsdorf Abstract Cyclins and cyclin-dependent kinases (Cdks) are the main components that control the orderly progression through cell cycle. In the mature nervous system, terminally differentiated neurons are permanently withdrawn from cell cycle, as mitotic quiescence is essential for the functional stability of the complexly wired neuronal system. Recently, we characterized the expression and colocalization of cyclins and Cdks in terminally differentiated pyramidal neurons. The functional impact of the expression of cell cycle-related proteins in differentiated neurons, however, has not been elucidated yet. In the present study, we show by immunoelectron microscopy and immunobiochemical methods an association of cyclins and Cdks with the microtubule network. Cyclins D, E, A and B as well as Cdks 1, 2 and 4 were also found to be associated with the microtubule-associated protein tau. Cyclin/Cdk complexes, in addition, exhibit kinase activity towards tau. In vitro, downregulation of cyclins and Cdks by a siRNA approach and by pharmacological inhibition promotes neurite extension. Taken together, these results indicate that the expression of cell cycle-related proteins in terminal differentiated neurons is associated with physiological functions beyond cell cycle control that might be involved in microtubule-based mechanisms of neuroplasticity. [source] Neuronal cell adhesion molecule deletion induces a cognitive and behavioral phenotype reflective of impulsivityGENES, BRAIN AND BEHAVIOR, Issue 4 2008L. D. Matzel Cell adhesion molecules, such as neuronal cell adhesion molecule (Nr-CAM), mediate cell,cell interactions in both the developing and mature nervous system. Neuronal cell adhesion molecule is believed to play a critical role in cell adhesion and migration, axonal growth, guidance, target recognition and synapse formation. Here, wild-type, heterozygous and Nr-CAM null mice were assessed on a battery of five learning tasks (Lashley maze, odor discrimination, passive avoidance, spatial water maze and fear conditioning) previously developed to characterize the general learning abilities of laboratory mice. Additionally, all animals were tested on 10 measures of sensory/motor function, emotionality and stress reactivity. We report that the Nr-CAM deletion had no impact on four of the learning tasks (fear conditioning, spatial water maze, Lashley maze and odor discrimination). However, Nr-CAM null mice exhibited impaired performance on a task that required animals to suppress movement (passive avoidance). Although Nr-CAM mutants expressed normal levels of general activity and body weights, they did exhibit an increased propensity to enter stressful areas of novel environments (the center of an open field and the lighted side of a dark/light box), exhibited higher sensitivity to pain (hot plate) and were more sensitive to the aversive effects of foot shock (shock-induced freezing). This behavioral phenotype suggests that Nr-CAM does not play a central role in the regulation of general cognitive abilities but may have a critical function in regulating impulsivity and possibly an animal's susceptibility to drug abuse and addiction. [source] | ||||||||||