Biomedical subjects

Galina G Skibo

Publications and source records attributed to Galina G Skibo.

4 recordsLinked to original sources

PubMed2005

A synthetic NCAM-derived peptide, FGL, protects hippocampal neurons from ischemic insult both in vitro and in vivo.

There is a major unmet need for development of innovative strategies for neuroprotection against ischemic brain injury. Here we show that FGL, a neural cell adhesion molecule (NCAM)-derived peptide binding to and inducing phosphorylation of the fibroblast growth factor receptor (FGFR), acts neuroprotectively after an ischemic insult both in vitro and in vivo. The neuroprotective activity of FGL was tested in vitro on dissociated rat hippocampal neurons and hippocampal slice cultures, using a protocol of oxygen-glucose deprivation (OGD). FGL protected hippocampal neurons from damage and maintained or restored their metabolic and presynaptic activity, both if employed as a pretreatment alone to OGD, and if only applied after the insult. In vivo 24 h pretreatment with a single suboccipital injection of FGL significantly protected hippocampal CA1 neurons from death in a transient global ischemia model in the gerbil. We conclude that FGL promotes neuronal survival after ischemic brain injury.

Animals↗

PubMed2004

Technique to quantify local clustering of synaptic vesicles using single section data.

Synaptic vesicles are organelles that specialize in the storage of a neurotransmitter that continuously undergo an exo-endocytotic cycle. During this cycle vesicles change their positions within a presynaptic terminal and their numbers as well as spatial arrangement can provide insight into a neurotransmitter turnover. This article introduces a technique based on the nearest-neighbor formalism to quantify the proximity of vesicles to active zones and vesicle clustering in different regions of a terminal. The technique, implemented in a software package, uses the two-dimensional coordinates of features identified in digitized electron micrographs as an input. It has been validated in the analysis of asymmetric synapses of the rat hippocampal CA1 stratum radiatum affected by transient cerebral ischemia. It was shown that a 15-minute-long ischemic episode influenced the spatial arrangement of vesicles that were more distant from active zones and had larger intervesicle spacings with respect to the control. The latter effect was apparently stronger within 200 nm distance of active zones.

Animals↗

PubMed2002

Post-tetanic depression of GABAergic synaptic transmission in rat hippocampal cell cultures.

The effect of tetanic stimulation (30 Hz, 4 s) on evoked GABAergic inhibitory postsynaptic currents (IPSCs) was studied in cell cultures of dissociated hippocampal neurons with established synaptic connections. It was found that tetanic stimulation elicited post-tetanic depression (PTD) of the evoked IPSCs with a duration of more than 50 s in about 60% of the connections tested; post-tetanic potentiation was induced in 25% of the connections. We propose that the opposite effects of tetanization on IPSC amplitude are due to differences in the type of the interneuron that was tetanized. Since PTD in our experiments was usually accompanied by changes in the IPSC coefficient of variation and changes of a paired pulse depression, which are thought to reflect presynaptic mechanisms of modulation, we suggest that part of the PTD is due to a presynaptic mechanism(s).

Animals↗

PubMed2002

Extracellular matrix heparin induces alteration of the cell adhesion during brain development.

The studies of neuronal cell-glycosaminoglycan interactions indicate an increasing interest in the question of how heparin can mediate adhesion properties of the cell. We have found that high levels of both N-CAM concentration and heparin-binding activity were noticed in the early stages of brain formation. According to electron microscopy data, an elevation of free heparin in the substratum leads to a decrease of the N-CAM content and changing of its distribution on the membrane of cultured hippocampal neurons. Spatial arrangement of immunogold labelled N-CAM molecules in plasma membrane profiles of cultured neurones was quantified with image analysis software using an interlabel distance estimate. To convert these estimates into two dimensional (2D) quantities, namely the 2D pattern and density of labelling, a computer simulation technique was used. Heparin added to the substratum in a concentration of 40 microg/ml decreased the 2D N-CAM labelling density by 50% - 39.8 labels/microm(2) compared with the control values of 88.9 labels/microm(2).

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