Authors: K I Kuznetsov V Yu Maslov S A Fedulova N S Veselovsky
Publish Date: 2011/06/10
Volume: 43, Issue: 1, Pages: 8-13
Abstract
Using the voltage/current clamp technique in the wholecell configuration we studied the role of the highly tetraethylammonium TEA sensitive component of integral potassium current in the generation of highfrequency tonic impulsation by rat retinal ganglion cells RGCs Application of 05 mM TEA led to a decrease in the frequency of evoked tonic impulsation by RGCs by 63 from 55 ± 10 sec–1 in the control to 26 ± 5 sec–1 in the presence of the blocker n = 11 In this case the duration of single action potentials at the level of 50 their amplitude increased by 64 from 11 ± 01 to 18 ± 01 msec n = 11 the rate of repolarization decreased by 54 from −101 ± 9 to −46 ± 5 mV/msec n = 11 and the amplitude of afterhyperpolarization dropped by 62 from −16 ± 2 to −6 ± 2 mV n = 11 Upon the action of 05 mM TEA the amplitude of the integral potassium current in RGCs decreased the current component sensitive to the above blocker was equal to 041 ± 005 nA n = 6 while the respective value in the control was 162 ± 014 nA n = 12 Thus a moderate on average by 25 decrease in the amplitude of the above potassium current significantly influenced the characteristics of impulse activity generated by RGCs The TEAsensitive component of the current was similar to the Kv31/Kv32 potassium current described earlier The obtained data are indicative of the key role of the highly TEAsensitive component of the potassium current passed probably via Kv31/Kv3 channels in highfrequency tonic activity generated by RGCs
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