Ultrastructural Changes in the Penumbra of the Local Cerebral Infarction in Rats.

We studied changes in the ultrastructure of synapses and myelin nerve fibers that develop in the penumbra in 4 and 12 h and 2 and 4 days after modeling infarction in the frontoparietal cortex in rats. Ischemic stroke was induced by injection of a photosensitive dye into their bloodstream followed by illumination of the brain surface with a halogen lamp. Visible ultrastructural changes were observed in the penumbra zone, namely in the axodendritic and axospinous synapses; they consisted in polymorphism and disorganization of synaptic vesicles, mitochondrial swelling, swelling and vacuolization of the postsynaptic fragments of dendrites, and shortening and osmiophilia of the active zone.

Electron microscopy demonstrating noise exposure alters synaptic vesicle size in the inferior colliculus of cat.

Context: White noise is known to have detrimental effects on different brain regions, especially auditory regions, including inferior colliculus. Although the basis for such alterations has been hypothesized to result from abnormalities in neurotransmitter release, the mechanism is unclear. The final step in neurotransmission is the docking and transient fusion of synaptic vesicles at the base of cup-shaped lipoprotein structures called porosomes at the presynaptic membrane and the consequent release of neurotransmitters.

White noise and neuronal porosome complex: transmission electron microscopic study.

In the present electron microscopic study the effect of continuous white noise on the morphology of synapses and neuronal porosome complex (the neurotransmitter-release or secretory machinery) in two subcortical auditory brain regions - colliculus inferior and medial geniculate body in cat, were investigated. Several morphological alterations in some synapses were detected in both subcortical areas. These alterations mainly indicate to the decrease of functional activity of synapses.

[Effect of short-term manganese chloride intoxicatuion on anxiety and fear of young rats].

Manganese is an essential trace element for all living organisms. Though some neurological dysfunction take place during intoxication caused by excessive exposure of this metal. The goal of this research was to elucidate the emotional state, in particular anxiety and fear in three groups of young male rats.

[Porosome: a new organelle and the universal secretion machine in cells].

A new cell organelle, porosome, discovered in the mid 1990's and its demonstration as the universal secretory machinery in cells is described. In contrast to the generally accepted belief that the secretory vesicle membrane is totally incorporated into the plasma membrane during cell secretion, it has been shown that secretory vesicles transiently dock and fuse with the porosome base via SNARE proteins to expel vesicular contents under intravesicular pressure which is generated by active transport of water through water channels located at the secretory vesicle membrane.