Lunko O. Modulation of Large conductance cationic channels of the inner nuclear membrane of rat cerebellar Purkinje neurons

Thesis presents the results of LCC (Large Conductance Cationic) channels modulation of the nuclear membrane of Purkinje neurons. Hypothetically, these channels are involved in the formation of potassium ions balance on the both sides of the inner and outer nuclear membranes. Since these channels might regulate nuclear envelope charge they could be important for calcium signal duration. However, the structure, amino acid sequence and function of LCC channels are still unknown. There is no enough quantitative description of the LCC channels kinetics and identified pharmacological profile, so that we could confirm, refute, or develop the existing hypothesis. In this dissertation, the first blocker of LCC channels was found – d-tubocurarine (dTC). The modulating effect of trivalent gadolinium ions, as well as the effect of gallamine on LCC channels was determined. For the first time, using the β-distribution analysis the rapid conformational changes of LCC channels were characterized and kinetic model was created. It was found that adequate kinetic model for LCC channels consists of one open state associated with three closed states characterized by different rate constants, and one sublevel. The efficiency of selected model and β-distribution analysis method has been proven by using gallamine, the fast blocker of LCC channels. It was determined that gallamine acts as a classical pore blocker. Moreover, the sensitivity parameters of the blocker to applied membrane potential were calculated.