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G P Galabov

Publications and source records attributed to G P Galabov.

12 recordsLinked to original sources
PubMed1983

Radioautographic study of the axonal transport of proteins into the sensory nerve endings of avian mechanoreceptors.

The axonal transport of proteins to the nerve endings of Herbst and Grandry sensory receptors has been investigated by electron-microscope radioautography. Soon after the injection of [3H]leucine into the trigeminal ganglia of young ducks, labeled proteins are conveyed along the suborbital sensory nerves to the sensory nerve endings at rates of at least 200-280 mm/day. Most of these rapidly transported proteins accumulate in areas containing vesicles of various kinds and along the axolemmal region. Later, the bulk of labeled proteins migrate along the axons at rates of about 15 mm/day and are distributed mainly to the mitochondria. A small portion of labeled material is transferred to the adjoining modified Schwann and specialized Grandry receptor cells. It is concluded that the transport of proteins from sensory ganglia to sensory nerve endings of mechanoreceptors is conveyed at fast and intermediate rates and is mainly used for the renewal of vesicles, axolemmal constituents and mitochondria.

Animals↗
PubMed1982

Electron microscopic evidence for the existence of a corticonigral tract in the cat.

Young adult cats were subjected to unilateral ablation of the frontal and prefrontal cerebral cortex and were allowed to survive for 4 to 5 days. Routine electron microscopic technique was employed to examine orthograde degenerative changes in the ipsilateral and contralateral substantia nigra (Ni). A moderate number of degenerating synaptic boutons (d. s. b.) were observed in the ipsilateral Ni-pars comacta, and only very few d.s.b. were observed in the ipsilateral Ni-pars reticulata. The d. s. b. exhibited features attributed to the dark degeneration type, and might be referred to two main categories; "small-round-vesicle bouton" and "large-round-vesicle bouton" (Hajdu et al., 1973; Hassler et al. 1975). The d. s. b. performed asymmetrical synapses with dendrites of varying size, much more rarely -- with the neuronal perikarya, and extremely rarely -- with initial axonal segments. No degeneration was observed in the contralateral Ni.

Animals↗
PubMed1982

The fate of newly synthesized proteins in nerve and glial cells following nerve injury as shown by electron microscope radioautography.

Following peripheral crush of hypoglossal nerve the fate of newly synthesizing proteins in corresponding nerve and glial cells was traced out using light and high resolution radioautography after intraventricular injection of 3H-leucine. Radioautographic analysis was applied on the normal and chromatolytic neurons and their glial surroundings 45 min after injection of labelled precursor. Both chromatolytic neurons and surrounding glia showed higher incorporation of labelled proteins than those of control nerve and glial cells. Relative specific radioactivity (RSR) of ergastoplasm and lysosomes were increased in the chromatolytic neurons, whereas RSR of nuclei, mitochondria and Golgi apparatus were decreased. Contrary to neurons, RSR of corresponding compartments in experimental glial cells except lysosomes showed reciprocal values in comparison with control glial cells. The higher RSR of mitochondria and Golgi apparatus in experimental glial cells depended mostly on the astrocytes, whereas those of nuclei and lysosomes were related first of all with microglial cells. These findings are correlated with present concepts of the complex interdependency between neurons and glia in which mutual regulatory controls and influences are exerted.

Animals↗
PubMed1981

Modified Nauta and Fink-Heimer procedures with special reference to the demonstration of monoaminergic pathways in the central nervous system.

Modifications of the selective silver impregnation methods of Nauta and Fink-Heimer are described. Both procedures were tested in wide variety of species: from reptiles to carnivores, as well as in human autoptic cases. The modified Nauta procedure is recommended as a method of choice for tracing axonal trajectories due to an improved impregnation selectivity of the degenerating axoplasm. Its use for the demonstration of monoaminergic (NA, DA, 5-HT) pathways, however, remains limited. The modified Fink-Heimer procedure demonstrates successfully the degeneration of axons, and especially--the thin preterminal arborizations, as well as the terminal boutons in many fiber systems studied, including the nigrostriatal, raphe-nigral, and coerulocortical tracts. Both methods provide an additional cytoarchitectonic orientation due to a counterstain of nerve cell bodies with cresylechtviolett.

Animals↗