PECULIARITIES OF NEURODEGENERATION IN HIPPOCAMPUS FIELDS
AFTER KAINIC ACID ACTION IN RATS
R.Ya. Gordon,1,* L.V. Shubina,2 M.V. Kapralova,2 E.B. Pershina,2,3
S.S. Khutzian,1,2 V I. Arhipov 2,3
1 Institute of Cell Biophysics, RAS, 2 Institute of Theoretical and Experimental Biophysics RAS, Pushchino,
and 3 Pushchino State Institute of Natural Sciences;
* e-mail: ritagordon@yandex.ru
Comparison between results of different ways of application of excitotoxin (kainic acid, KA), intrahippocampal
(0.2 μg/ml) and intraventricular (0.6 μg/ml), was carried out in the course of investigations of the prolonged
action of KA on the morphological state of various fields in dorsal hippocampus. Light microscopy with
Cresyl Violet staining and fluorescent microscopy with staining by fluoro-jade B were used in our researches.
The results revealed that ÊA, being injected intrahippocampally at a dose, which does not result in animal epileptization,
caused obvious degenerative phenomena in hippocampus. Two weeks after ÊA injection the layers
of pyramid cells in the fields ÑÀ3 and ÑÀ4 were absent, and in four weeks, degenerative changes and cell lysis
were spread on the ÑÀ1 field as well. Four weeks after ÊA intraventricular administration in rats with epileptic
status the damages of various levels were observed in hippocampus, from partial injuries of pyramid neurons in
the fields ÑÀ3 and ÑÀ4 up to full loss of layers of pyramids in the fields ÑÀ1, ÑÀ3 and ÑÀ4. In both ways of
ÊA injection, in the ÑÀ2 field the layer of cells mainly remained undamaged what indicates a special role of
this field. After a single-time KA administration the both ways of injection led to the long-term damages of a
neural tissue, possibly, of a general character, but differing in rates of neuron reactions in different fields to the
damaging factor. An explanation of the prolonged action of ÊA excitotoxicity might be in the activation of
GluR6-containing kainate receptors in pyramid neurons in ÑÀ3 field which brings to chronic character in single-
time KA action and promotes the destruction of the remaining neurons by necrotic way while at the initial
stage of ÊA influence the neurons perish by apoptotic way.
Key words: excitotoxicity, neurodegeneration, hippocampus, fields ÑÀ1—ÑÀ4,
kainic acid, fluoro-jade B
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