Gb. Murzina et Ig. Sikis, STUDY OF THE LTP AND LTD OF INHIBITORY TR ANSMISSION USING MATHEMATICAL SIMULATION OF POSTSYNAPTIC PROCESSES, Zurnal vyssej nervnoj deatelnosti im. I.P. Pavlova, 46(5), 1996, pp. 917-928
The mathematical model of calcium-dependent posttetanic processes in a
dendritic spine of a CA(3) hippocampal pyramidal neuron which receive
d excitatory and inhibitory afferents was used for studying the LTP an
d LTD of inhibitory transmission. It has been demonstrated that the in
hibitory synaptic efficacy is difined by GABAa and GABAb dephosphoryla
tion which, in turn, is determined by the Ca2+-dependent ratio between
the active protein kinases and protein phosphatases. Posttetanic decr
ease/increase in intracellular Ca2+ concentration (Ca(2+)p) in respect
of pretetanic Ca2+ level results in an increase/decrease in number of
dephosphorylated GABA receptors and in the LTP/LTD of the efficacy of
inhibitory transmission. The extent of modification depends on the ra
tio between the concentrations of excitatory and inhibitory transmitte
rs in a synaptic cleft. The extent of inhibitory transmisson modificat
ion is negligible if GABA concentration is very low or high.