Українська English

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.

Full text: (PDF, in Ukrainian)

References

  1. Brown D. A., Adams P. R. Muscarinic suppression of a novel voltage-sensitive K+ current in a vertebrate neurone // Nature. – 1980. – 283, № 5748. – P. 673–676.
  2. Burgess N., Maguire E. A., O’Keefe J. The human hippocampus and spatial and episodic memory // Neuron. – 2002. – 35, №4. – P. 625–641.
  3. Chikwendu A., McBain C. J. Two temporally overlap- ping «delayed-rectifiers» determine the voltage-depen- dent potassium current phenotype in cultured hippoc- ampal interneurons // J.Neurophysiol. – 1996. – 76,№3. – P. 1477–1490.
  4. Coetzee W. A., Amarillo Y., Chiu J. et al. Molecular diversity of K+ channels // Ann.N.Y.Acad.Sci. – 1999. – 868. – P. 233–285.
  5. Fedulova S. A., Vasilyev D. V., Isaeva E. V. et al. Pos- sibility of multiquantal transmission at single inhibi- tory synapse in cultured rat hippocampal neurons //Neuroscience. – 1999. – 92, № 4. – P. 1217–1230.
  6. Freund T. F., Buzsaki G. Interneurons of the hippocam- pus // Hippocampus. – 1996. – 6, № 4. – P. 347–470.
  7. Gulyas A. I., Toth K., McBain C. J. et al. Stratum
  8. 44ISSN 0201-8489 Фізіол. журн., 2006, Т. 52, № 6 radiatum giant cells: a type of principal cell in the rat hippocampus // Eur.J.Neurosci. – 1998. – 10, № 12. – P. 3813–3822.
  9. Jan L. Y., Jan Y. N. Voltage-gated and inwardly rectifying potassium channels // J.Physiol. – 1997. – 505, № 2. – P. 267–282.
  10. 9. Madison D. V., Nicoll R. A. Control of the repetitive discharge of rat CA 1 pyramidal neurones in vitro // J.Physiol. – 1984. – 354. – P. 319–331.
  11. 10. Main M. J., Cryan J. E., Dupere J. R. et al. Modula- tion of KCNQ2/3 potassium channels by the novel anticonvulsant retigabine // Mol.Pharmacol. – 2000. – 58, №2. – P. 253–262.
  12. Martina M., Schultz J. H., Ehmke H. et al. Functional and molecular differences between voltage-gated K+ channels of fast-spiking interneurons and pyramidal neurons of rat hippocampus // J.Neurosci. – 1998. – 18, №20. – P. 8111–8125.
  13. Ottschytsch N., Raes A., Van Hoorick D. et al. Obliga- tory heterotetramerization of three previously uncharacterized Kv channel alpha-subunits identified in the human genome // Proc.Natl.Acad.Sci.U.S.A. – 2002. – 99, №12. – P. 7986–7991.
  14. Passmore G. M., Selyanko A. A., Mistry M. et al. KCNQ/M currents in sensory neurons: significance for pain therapy // J.Neurosci. – 2003. – 23, №18. – P.7227–7236.
  15. Rudy B., Chow A., Lau D. et al. Contributions of Kv3 channels to neuronal excitability // Ann.N.Y.Acad.Sci. – 1999. – 868. – P. 304–343.
  16. Rundfeldt C., Netzer R. The novel anticonvulsant retigabine activates M-currents in Chinese hamster ovary-cells tranfected with human KCNQ2/3 subunits // Neurosci.Lett. – 2000. – 282, №1–2. – P. 73–76.
  17. Savic N., Pedarzani P., Sciancalepore M. Medium afterhyperpolarization and firing pattern modulation in in- terneurons of stratum radiatum in the CA3 hippocampal region // J.Neurophysiol. – 2001. – 85, №5. – P. 1986–1997.
  18. Schnee M. E., Brown B. S. Selectivity of linopirdine (DuP 996), a neurotransmitter release enhancer, in blocking voltage-dependent and calcium-activated potassium currents in hippocampal neurons // J. Pharmacol.Exp.Therap. – 1998. – 286, №2. – P. 709–717.
  19. Shah M. M., Mistry M., Marsh S. J. et al. Molecular correlates of the M-current in cultured rat hippocampal neurons // J.Physiol. – 2002. – 544, №1. – P. 29–37.
  20. 19. Storm J. F. Temporal integration by a slowly inacti- vating K+ current in hippocampal neurons // Nature. – 1988. – 336, №6197. – P. 379–381.
  21. 20. Storm J. F. Potassium currents in hippocampal pyramidal cells // Prog.Brain Res. – 1990. - 83. – P. 161-187.
  22. Tatulian L., Delmas P., Abogadie F. C. et al. Activation of expressed KCNQ potassium currents and native neuronal M-type potassium currents by the anti-convulsant drug retigabine // J.Neurosci. – 2001. – 21,№ 15. – P. 5535–5545.
  23. Veselovsky N. S., Engert F., Lux H. D. Fast local superfusion technique // Pflug. Arch. – 1996. – 432, №2. – P. 351–354.
  24. Wang H. S., Brown B. S., McKinnon D. et al. Molecu-lar basis for differential sensitivity of KCNQ and I(Ks) channels to the cognitive enhancer XE991 // Mol. Pharmacol. – 2000. – 57, №6. – P. 1218–1223.
  25. Wang H. S., Pan Z., Shi W. et al. KCNQ2 and KCNQ3 potassium channel subunits: molecular correlates of the M-channel // Science. – 1998. – 282, №5395. – P. 1890–1893.
  26. Wu R. L., Barish M. E. Two pharmacologically and kinetically distinct transient potassium currents in cultured embryonic mouse hippocampal neurons //J.Neurosci. – 1992. – 12, № 6. – P. 2235–2246.
© National Academy of Sciences of Ukraine, Bogomoletz Institute of Physiology, 2014-2024.