Large-conductance cationic channels (LCC) expressed on the Pukinje neuron nuclei of the rat cerebellum, characterized by selectivity to monovalent cations, slow kinetics and potentialdependent activity. The identification of a specific LCC channel blocker is the first step in determining their structure and physiological role. In order to identify components that specifically interact with LCC channels on the inner nuclear membrane, we investigated the effects of venoms of five animals: forest scorpion (Heteromerus laoticus), monocled cobra (Naja kaouthia), steppe viper (Vipera renardi), banded krait (Bungarus fasciatus), and puff adder (Bitis arietans) on the characteristics of these channels. It has been shown that all investigated venoms significantly reduce the open state probability of LCC channels in average by 76 - 86%. The application venoms of H. laoticus and B. fasciatus leads to a decrease in the currents amplitude of LCC channels, by 43% and 26% respectively. The influence of other compounds as blocker of LCC channels was less pronounced. Obtained data can be used for further direct search of specific and high affinity blockers of these channels.