Функціонування катіонних каналів великої провідності ядерної мембрани під впливом модуляторів нікотинових холінорецепторів

Large conductance cationic channels (LCC-channels) are highly expressed in the nuclear envelope of neurons and cardiomyocytes. Using electrophysiological registration of ion currents through the inner nuclear membrane of cardiomyocytes and cerebellar Purkinje neurons, we have tested the effect of n-choline receptor modulators (activators and inhibitors) on LCC-channels. Among the substances tested, rocuronium- and pipecuronium-bromide and nicotine proved to be effective. The pharmacological sensitivity of LCC-channels in Purkinje neuron and cardiomyocyte nuclear membranes was almost identical, indicating existence of a single population of these channels in the tissues studied. At a concentration of 0.2 mM nicotine reduced in half the current through LCC-channels, while rocuronium- and pipecuroniumbromide at the same concentration inhibited these channels by 7 and 12 % respectively. Therefore, among the listed substances, only the effect of nicotine on LCC-channels was close to the effect of previously studied tubocurarine, that's why tubocurarine and nicotine remain the most promising tools for further investigation of the physiological role of these channels. [ABSTRACT FROM AUTHOR]