Ultrastructural parameters of GABA-ergic and non-GABA-ergic synaptic contacts on neurons of the catsubstantia nigra

Autor: V. K. Berezovskii, J. Takacs, L. F. Burchinskaya, V. A. Maiskii, M. Ya. Voloshin
Rok vydání: 1995
Předmět:
Zdroj: Neurophysiology. 27:115-124
ISSN: 1573-9007
0090-2977
DOI: 10.1007/bf01305382
Popis: Nigrothalamic neurons were identified in the reticular part of thesubstantia nigra using labelling by the retrograde axonal transport of horseradish peroxidase. Nine parameters of the synaptic contacts (n=195) were analyzed, including the size and shape of terminals and size and type of synaptic vesicies. Sixty-six percent of axon terminals studied formed symmetric contacts and contained large polymorphic vesicles (group I). Two-thirds of these synapses were located on the distal dendrites, while one-third was distributed on the perikarya and proximal dendrites. Synapses of group II (29% of all synapses analyzed) exhibited asymmetric contacts and contained round agranular vesicles. Among these synapses, 79% were located on the distal dendrites, 19% were located on the proximal dendrites, and only 2% were located on the neuronal perikarya. Axon terminals of group III (5% of total population) exhibited symmetric contact and contained small polymorphic vesicles. High-resolution immunogold EM histochemistry indicated that 63% of the group-I axon terminals were GABA-positive. The majority of synapses on the labelled nigrothalamic neurons (21 contacts of 25) belonged to group I. Among these 21 synapses, 19 were axo-somatic and mostly GABA-positive. Within group II, 30% of synapses showed slightly expressed GABA-positivity.
Databáze: OpenAIRE
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