K H Körtje

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By means of newly developed electron microscopical techniques (electron spectroscopic imaging, ESI; electron energy loss spectroscopy, EELS; immunogold labelling) a specific accumulation of endogenous calcium within the synaptic cleft and a distinct localization of a high-affinity Ca(2+)-ATPase at the inner sides of the pre- and postsynaptic membrane of(More)
The patterns of the anterior lateral-line afferents of Lampetra fluviatilis as revealed by transganglionic transport of horseradish peroxidase are described. The afferents form two roots in entering the rhombencephalon. Fibers of the dorsalmost root can be traced to a short dorsal fascicle which runs along the dorsal nucleus. The ventral roots form two(More)
Cichlid fish larvae were reared from hatching to active free swimming under different gravity conditions: natural environment, increased acceleration in a centrifuge, simulated weightlessness in a clinostat and near weightlessness during space flight. Cytochrome oxidase activity was analyzed semiquantitatively on the ultrastructural level as a marker of(More)
The mitochondrial enzyme, cytochrome oxidase, was localized cytochemically in the nucleus magnocellularis, a primary relay nucleus of vestibular information within the area octavolateralis in the fish brain. Cichlid fish larvae were analyzed after long-term exposure (9 days) to altered gravity situations: increased acceleration in a centrifuge (3 g) and(More)
Electron microscopy of nervous tissue requires on the one hand nanometre resolution for the analysis of fine structures of nerve cell contacts, for instance synaptic vesicles, synaptic membranes and associated organelles. On the other hand, the visualization of the three-dimensional organization of nervous tissue on the level of dendrites and neurites is(More)
The regional metabolic activity in the otolithic sensory epithelia of the inner ear of a cichlid fish (Oreochromis mossambicus) was investigated on light- and electronmicroscopical level using the cytochemical method for detection of cytochrome oxidase activity. In adult animals a characteristic distribution of mitochondria with high enzyme activity was(More)
Energy-filtering transmission electron microscopy has been applied to the quantification of area fractions of calcium-containing cytochemical reaction products in central nervous tissue and the retina of fish. The method of electron spectroscopic imaging using electrons with an energy loss of 250 eV produces images with a very high, structure-sensitive(More)
In this study the extracellular distribution of cytochemically generated calcium reaction product in the denervated optic tectum of a cichild fish (Oreochromis mossambicus) was investigated. The left optic nerve had been transected and the fish (5 per experimental condition) maintained for 2, 10 and 21 days. The amount of the calcium-containing precipitates(More)
Cytochrome oxidase activity was evaluated cytochemically in rod photoreceptor cells in the retina of the cichlid fish Oreochromis mossambicus after different stimulation protocols. The enzyme activity was assessed semiquantitatively by estimating the volume ratio of mitochondria classified according to the intensity of enzyme reactivity. Dark adaptation for(More)