EFFECT OF A POLYPHENOL COMPOUND
ON THE TRANSPORT OF CALCIUM MEMBRANE
OF SYNAPTOSOMES IN RAT BRAIN
Saidmurodov S.A., Khoshimov N.N., Azizov V.G., Rakhimov R.N.
National University of Uzbekistan,
Institute of Biophysics and Biochemistry
at the National University of Uzbekistan,
Namangan State University,
Institute of Bioorganic Chemistry Academy of Sciences of Uzbekistan,
Tashkent, Uzbekistan
Academic supervisor: Nasirov K.E., D. sci. (Biology), Prof.
Introduction.
It is known that the activation of NMDA receptors
under the influence of glutamate can cause pathological changes in
excitotoxicity associated with increased penetration of Ca
2+
into the cell,
followed by neuronal death. The excitotoxicity of glutamate plays a role
in the pathogenesis of a number of neurological diseases, while cell death
itself can be a consequence of both necrosis and apoptosis (programmed
cell death). Correction of glutamate transport using polyphenolic
compounds is urgent.
Purpose.
The effect of polyphenolic compounds — 5 (PC-5) on Ca
2+
transport across the membrane of rat brain synaptosomes was studied.
Мethods.
The synaptosomes were purified from the rat brain by two-
stage centrifugation. Measure the amount of intracellular calcium [Ca
2+
]
in was calculated by the Grinkevich equation.
Results.
In the experiments, investigated using the Ca
2+
— sensitive
probe chlortetracycline (CTC), the ratio of fluorescence excited by light
with wavelengths of 340 and 380 nm (F340 / F380) in the synaptosomes
of the rat brain was established. Removal of Ca
2+
from the extracellular
medium, preincubated with EGTA, resulted in a 5% decrease in
fluorescence. In the presence of glutamate in the incubation medium
at concentrations of 1-100 μM, dose-dependently increases the level of
fluorescence by 25-30%, which indicates an increase in the concentration
of Ca
2+
in the cytosol [Ca
2+
]in, caused by glutamate, primarily due
to [Ca
2+
]in. When studying the effect of PS-5 on synaptosomes, it was
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ФАРМАКОЛОГИЯ, ФАРМАКОГНОЗИЯ, ФАРМАЦЕВТИКА, ТОКСИКОЛОГИЯ
revealed that PS-5 insignificantly increases fluorescence according to the
[Ca
2+
] in level in comparison with the control. Pre-incubation of PC-5
(50 μM) with synaptic membranes, followed by addition of CTC-glutamate
resulted in a decrease in fluorescence and [Ca
2+
] in level, respectively.
A dose-dependent increase in the concentration of PC-5 to 10-100 μM,
respectively, led to a dose-dependent decrease in the effect of glutamate.
Conclusion.
The results obtained show a possible competition
between PC-5 and glutamate for the site of regulation of the opening of
ion channels.
ФАРМАКОЛОГИЯ, ФАРМАКОГНОЗИЯ, ФАРМАЦЕВТИКА, ТОКСИКОЛОГИЯ
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