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ISSN 2522-9028 (Print)
ISSN 2522-9036 (Online)
DOI: https://doi.org/10.15407/fz

Fiziologichnyi Zhurnal

is a scientific journal issued by the

Bogomoletz Institute of Physiology
National Academy of Sciences of Ukraine

Editor-in-chief: V.F. Sagach

The journal was founded in 1955 as
1955 – 1977 "Fiziolohichnyi zhurnal" (ISSN 0015 – 3311)
1978 – 1993 "Fiziologicheskii zhurnal" (ISSN 0201 – 8489)
1994 – 2016 "Fiziolohichnyi zhurnal" (ISSN 0201 – 8489)
2017 – "Fiziolohichnyi zhurnal" (ISSN 2522-9028)

Fiziol. Zh. 2006; 52(6): 35-44


Voltage-activated potassiumchannels of the inhibitory interneurons of hippocampal culture

O.O.Grygorov, A.O.Moskalyuk, S.A.Fedulova, N.S.Veselovsky

    O.O. Bogomoletz Institute of Physiology, National Academyof Sciences of Ukraine, Kyiv, Ukraine;International Centre for Molecular Physiology, Kyiv


Abstract

Potassium channels make up the largest family of voltage- activated channels and play a key role in maintenance of cell excitability and in transmission of information within the nervous system. The aim of this work was to find out the specific subtypes of voltage-activated potassium channels peculiar to GABAergic interneurons of rat hippocampal culture. It was shown that total depolarization-evoked outward po- tassium current in any interneuron studied had the activation threshold about -50 mV. The specific Kv1 channels’ blocker a- DTX influenced neither amplitude nor kinetics of total current, thus we excluded the participation of these channels in its forming. The transient A-current made up 9.4±1.3% of the amplitude of total current and had low sensitivity to 4-AP that was an evidence of the presence of Kv4 channels in hip- pocampal interneurons. The slow inactivating component of integral potassium current was relatively small and had the time constant of inactivation 3 ± 0.15 s that is typical for delayed rectifier potassium channels of Kv2 and Kv3 sub- families. The main contribution (83 ± 1.7 % of total ampli- tude) to the integral current belonged to the non-inactivating current. Prolonged depolarization of any interneuron tested to –20 mV evoked a steady non-inactivating outward current with amplitude 100-400 pA and activation threshold about –60 mV. Retigabine shifted its I-V plot to more negative values and increased the amplitude at –20 mV by 66±14%. These facts can be evidence of the participation of KCNQ channels sub- family in the forming of non-inactivating current. But selective blockers of KCNQ channels linopirdine and XE991 had very small influence on steady-state outward current that means the current appears owing to activity of linopirdine-insensitive forms of KCNQ channels or channels of a different, unknown family.

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