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ANALYSIS OF QUANTAL PARAMETERS OF GABA RELEASE DURING SHORT-TERM DEPRESSION AND FACILITATION OF SYNAPTIC TRANSMISSION
О.P. Кolesnyk, S.А.Fedulova, N.S. Veselovsky
O.O. Bogomolets Institute of Physiology, National Academy
of Sciences of Ukraine, Kyiv
DOI: https://doi.org/10.15407/fz62.05.012
Abstract
Changes in amplitudes of evoked inhibitory postsynaptic
currents (eIPSCs) from rat cultured hippocampal neurons
were studied using whole-cell patch-clamp technique in
postsynaptic neuron and local extracellular electrical paired
pulse stimulation of single presynaptic axon. Paired pulse
depression (PPD) and paired pulse facilitation (PPF) were
observed in studied 43 neurons. According to coefficient of
variance (CV) analysis was found that CV of second respond
was significantly larger than CV first by 57 % (n = 26) during
depression and significanty smaller by 27 % (n = 17) during
facilitation. Thus, only presynaptic mechanism underlies shortterm
depression and facilitation. We also estimated quantal
parameters assuming that transmitter release is reasonably
described by a binomial distribution. We found that under our
experimental conditions there were no significant changes in
GABA release probability during PPD and PPF. The values of
mean quantal content and mean number of sites of transmitter
release were the same for first stimulus in pair and were equal
9.7 in depression and 5 in facilitation of synaptic transmission.
The values both of them for second stimulus were significant
decreased by 28 and 26% during PPD and were significant
increased by 14 and 11% during PPF, respectively. Thus, there
is significant difference in quantal parameters characterizing
GABA release during short-term depression and facilitation
of synaptic transmission.
Keywords:
PPD and PPF of GABAergic synaptic transmission; interstimulus interval; coefficient of variation.
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© National Academy of Sciences of Ukraine, Bogomoletz Institute of Physiology, 2014-2024.
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