MicroRNA regulation and the variability of human cortical gene expression

Understanding the driving forces of gene expression variation within human populations will provide important insights into the molecular basis of human phenotypic variation. In the genome, the gene expression variability differs among genes, and at prese

Differential amplitude modulation of auditory evoked cortical potentials associated with brain state in the freely moving rhesus monkey

We simultaneously recorded auditory evoked potentials (AEP) from the temporal cortex (TCx), the dorsolateral prefrontal cortex (dPFCx) and the parietal cortex (PCx) in the freely moving rhesus monkey to investigate state-dependent changes of the AEP. AEPs obtained during passive wakefulness, active wakefulness (AW), slow wave sleep and rapid-eye-movement sleep (REM) were compared. Results showed that AEP from all three cerebral areas were modulated by brain states. However, the amplitude of AEP from dPFCx and PCx significantly appeared greater attenuation than that from the TCx during AW and REM. These results indicate that the modulation of brain state on AEP from all three cerebral areas investigated is not uniform, which suggests that different cerebral areas have differential functional contributions during sleep-wake cycle. (C) 2002 Elsevier Science Ireland Ltd.. All rights reserved.

GABA and its agonists improved visual cortical function in senescent monkeys

Human cerebral cortical function degrades during old age. Much of this change may result from a degradation of intracortical inhibition during senescence. We used multibarreled microelectrodes to study the effects of electrophoretic application of gamma-aminobutyric acid (GABA), the GABA type a (GABAa) receptor agonist muscimol, and the GABAa receptor antagonist bicuculline, respectively, on the properties of individual V1 cells in old monkeys. Bicuculline exerted a much weaker effect on neuronal responses in old than in young animals, confirming a degradation of GABA-mediated inhibition. On the other hand, the administration of GABA and muscimol resulted in improved visual function. Many treated cells in area V1 of old animals displayed responses typical of young cells. The present results have important implications for the treatment of the sensory, motor, and cognitive declines that accompany old age.

Assessing functioning of the prefrontal cortical subregions with auditory evoked potentials in sleep-wake cycle

Our previously observations showed that the amplitude of cortical evoked potentials to irrelevant auditory stimulus (probe) recorded from several different cerebral areas was differentially modulated by brain states. At present study, we simultaneously re

Spatial and temporal sensitivity degradation of primary visual cortical cells in senescent rhesus monkeys

Human visual function declines with age. Much of this decline is mediated by changes in the central visual pathways. In this study we compared the spatial and temporal sensitivities of striate cortical cells in young and old paralysed macaque monkeys. Ext

Disconnection of the hippocampal-prefrontal cortical circuits impairs spatial working memory performance in rats

There is a unidirectional, ipsilateral and monosynaptic projection from the hippocampus to the prefrontal cortex. The cognitive function of hippocampal-prefrontal cortical circuit is not well established. In this paper, we use muscimol treated rats to inv

Reversible disconnection of the hippocampal-prelimbic cortical circuit impairs spatial learning but not passive avoidance learning in rats

Wistar rats, treated with the GABA(A) receptor agonist muscimol, were used to investigate the role of the hippocampal-prelimbic cortical (Hip-PLC) circuit in spatial learning in the Morris water maze task, and in passive avoidance learning in the step-thr

Identification of a C1q family member associated with cortical granules and follicular cell apoptosis in Carassius auratus gibelio

C1q family proteins with C1q domain have been reported in vertebrates, but their biological roles are currently unknown. In this study, a C1q-like factor, designated Carassius auratus gibelio ovary-specific C1q-like factor (CagOC1q-like), was identified as a cortical granules component. Immunofluorescence localization revealed that the C1q family member was specifically expressed in follicular epithelial cells, and associated with cortical granules in fully grown oocytes. Moreover, it was discharged to the perivitelline space and egg envelope upon fertilization. As it is the first identified C1q family member that is expressed in follicular cells that surround oocyte, CagOC1q-like was applied to detection of follicular cell apoptosis and deletion. The entire cytological process of follicular cell apoptosis and deletion was clearly seen from double visualizations of follicular cells with CagOC1q-like immunofluorescence and apoptotic follicular cells labeled by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) during oocyte maturation and ovulation. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

A C-type lectin associated and translocated with cortical granules during oocyte maturation and egg fertilization in fish

Oocyte maturation and egg fertilization in both vertebrates and invertebrates are marked by orchestrated cytoplasmic translocation of secretory vesicles known as cortical granules. It is thought that such redistribution of cellular content is critical for asymmetrical cell division during early development, but the mechanism and regulation of the process is poorly understood. Here we report the identification, purification and cDNA cloning of a C-type lectin from oocytes of a freshwater fish species gibel carp (Carassius auratus gibelio). The purified protein has been demonstrated to have lectin activity and to be a Ca2+-dependent C-type lectin by hemagglutination activity assay. Immunocytochemistry revealed that the lectin is associated with cortical granules, gradually translocated to the cell surface during oocyte maturation, and discharged to the egg envelope upon fertilization. Interestingly, the lectin becomes phosphorylated on threonine residues upon induction of exocytosis by fertilization and returns to its original state after morula stage of embryonic development, suggesting that this posttranslational modification may represent a critical molecular switch for early embryonic development. (C) 2003 Elsevier Inc. All rights reserved.

Study on cytocompatibility of carboxymethyl-chitosan membranes to skin fibroblasts

Chitosan and carboxymethl-chitosan (CM-chitosan) membranes with different molecular mass were prepared by a casting method. The cytocompatibility of two kinds of polysaccharide membranes to skin fibroblasts that cultured in vitro were studied. The methods were to culture the cells in soaking fluid of membranes and to culture the cells on the membranes directly. The results showed that the soaking fluid had no toxicity to fibroblasts and the biological security of lower molecular mass membranes were better than higher molecular mass membranes, and CM-chitosan membranes were better than chitosan membranes. In addition, the growth of fibroblasts on chitosan membranes was inhibited and the cells would fall off from chitosan membranes after a period of culture. However, the cells adhered and expanded well on CM-chitosan membranes. All these demonstrated that cytocompatibility of CM-chitosan membranes to skin fibroblasts was better than chitosan membranes.