<p>The paired-pulse stimulation method was used to study changes in the efficiency of inhibition during longterm potentiation in the CA1 field of rat hippocampal slices. Inhibition coefficients were calculated from the ratio of IPSP-dependent and IPSP-independent reactions. Tetanization of Schaffer collaterals was produced in experimental slices in the presence of jasplakinolide, a depolymerization inhibitor which is also used to induce actin polymerization. The characteristics of the development of LTP in CA1 during induction on the background of blockade of actin depolymerization included a change in the dynamics of modifications of the inhibitory component of reactions to paired-pulse stimulation. An initial increase in inhibition was dependent on the initial level, while changes after pre-tetanization application of jasplakinolide may be the main cause of between-group differences. This factor was therefore taken into account for analysis of changes specific to the blockade of the early phase of actin depolymerization. These were shown to include impairment of disinhibition processes in the consolidation and maintenance phases of LTP. It is suggested that the coordinating role of the actin cytoskeleton determines the balance of long-term modifications of excitatory and inhibitory synapses.</p>