Caspase-3 activity in the rat hippocampal slices reflects changes in synaptic plasticity

Considering the involvement of caspase-3 in neuronal plasticity, we studied caspase-3 activity in the rat hippocampal slices, and electrophysiological characteristics of extracellular responses to paired-pulse stimulation of Schaffer's collaterals in the CA1 subfield of hippocampus. Caspase-3 activity was measured after electrophysiological recording in each slice separately. Maximal caspase-3 activity was observed in the slices with low responsiveness to single afferent stimulation indicative of decreased efficacy of interneuronal interaction. This phenomenon is unrelated to depression of neuronal excitability since paired-pulse stimulation increases the synaptic efficacy to second stimulus thus restoring population spike amplitudes to normal values. In "damaged" slices with impaired spike generation up to disappearing spikes to both stimuli, caspase-3 activity was close to the normal level of the "healthy" slices. The activity of another proteinase, cathepsin B, was increased in the "damaged" slices, no correlation with the modifications of electrophysiological indices being detected. Our data suggest that high caspase-3 activity in hippocampal slices is involved in maintenance of synaptic plasticity but not necessarily related to apoptosis.     

Cy5-Labeled Phosphatidylcholine

Russian Journal of Bioorganic Chemistry - Fluorescent lipid probes are widely used as tools for studying the properties of biological membranes and for studies of such biological functions of...     

Analysis of plastid DNA-like sequences within the nuclear genomes of higher plants

A wide-ranging examination of plastid (pt)DNA sequence homologies within higher plant nuclear genomes (promiscuous DNA) was undertaken. Digestion with methylation-sensitive restriction enzymes and Southern analysis was used to distinguish plastid and nuclear DNA in order to assess the extent of variability of promiscuous sequences within and between plant species. Some species, such as Gossypium hirsutum (cotton), Nicotiana tabacum (tobacco), and Chenopodium quinoa, showed homogenity of these sequences, while intraspecific sequence variation was observed among different cultivars of Pisum sativum (pea), Hordeum vulgare (barley), and Triticum aestivum (wheat). Hypervariability of plastid sequence homologies was identified in the nuclear genomes of Spinacea oleracea (spinach) and Beta vulgaris (beet), in which individual plants were shown to possess a unique spectrum of nuclear sequences with ptDNA homology. This hypervariability apparently extended to somatic variation in B. vulgaris. No sequences with ptDNA homology were identified by this method in the nuclear genome of Arabidopsis thaliana.      

Expression of T-cadherin in the rat carotid artery wall after balloon injury and in different rat organs

T-cadherin is an unusual glycosilphosphatidylinositol (GPI)-anchored member of the cadherin family of cell adhesion proteins. In contrast to classical cadherins, tissue distribution of T-cadherin so far remained unknown. We examined tissue distribution of T-cadherin in rats using Western blotting and immunohistochemical method. Our results show that T-cadherin is expressed in all types of muscles (cardiac, striated, and smooth muscles), in brain neurons, and spinal cord, in the vessel endothelium, at the apical pole of intestinal villar epithelium, in the basal layer of skin, and eosophagal epithelium. Blood-derived and lymphoid cells as well as connective tissue were T-cadherin-negative. The highest level of T-cadherin expression was revealed in the cardiovascular system. Although T-cadherin was detected in smooth muscle cells, its role in the intimal thickening and restenosis is not known. We examined T-cadherin expression within 1-28 days after balloon injury of rat left carotid arteries. T-cadherin expression was valued immunohistochemically with semiquantitative method. In uninjured arteries, T-cadherin was expressed in endothelial (vWF-positive) cells, and smooth muscle (alpha-actin-positive) cells (SMCs). After denudation of arterial wall, T-cadherin was present both in the media and neointima. We revealed dynamics of T-cadherin expression in the media of injured artery: an essential increase being registered at the stage of cell migration and proliferation in the media and neointima (1-7 days), followed by its decrease to the baseline level (10-28 days). The high upregulation of T-cadherin expression in the media and neointima during migration and proliferation of vascular cells after vessel injury enables us to suggest the involvement of T-cadherin in vessel remodeling after balloon catheter injury.     

Physical criteria of pathological processes. III. Structure of the correlation between the level of steady brain potential with serum complement proteins in rheumatic diseases]

The activity of serum complement proteins and the level of steady brain potential in patients with systemic lupus erythematosus and rheumatoid arthritis were determined. The statistical analysis indicated that there is a correlation between the parameters of the complement system and neurophysiological characteristics. The differences between rheumatoid arthritis and systemic lupus erythematosus are observed in the mean values of activity of complement proteins and the steady potential, their dispersions, and the structure of correlations between immunological and neurophysiological parameters.     

Effects of caspase-3 inhibition on long-term potentiation in the hippocampus: analysis of paired pulse facilitation

Incubation of the rat hippocampal slices with caspase-3 inhibitor Z-DEVD-FMK resulted in a time-dependent decrease in long-term potentiation (LTP) magnitude. Analysis of paired pulse facilitation at a 70-msec interval revealed that, after caspase-3 inhibition, the increase in the amplitude of the second response in the pair during LTP that was characteristic for control slices, did not occur. In this situation, the LTP magnitude depended on differences in the amplitudes of the first and second responses before the LTP induction. LTP was absent in slices with initially high efficacy of the afferent stimulation and respective low paired pulse facilitation. The Caspase inhibition seems to prevent structural reorganization during the LTP related to involvement into the response of new synapses and neurons.     

Role of trophic and hormonal factors in exogenous regulation of the formation of reproductive organs in yellow lupine (Lupinus luteus L.)

During the formation and ripening of beans in yellow lupine, their intactness may be increased by treatment of the plants with the microelement molybdenum or the growth factor 24-epibrassinolide. Early stages of the effects of either factor involved activation of various metabolic pathways; eventually, the supply of fruit elements with free amino acids was improved and the seed productivity of the plants, increased.