Українська Русский 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. 2011; 57(3): 25-32


Changes in calcium-dependent potassium channels of isolated smooth muscle cells of the bladder in rats with experimental diabetes

Kryshtal' DA, Paduraru OM, Boldyriev OI, Kit OIu, Rekalov VV, Shuba IaM

  1. O.O.Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
  2. International Center of Molecular Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
DOI: https://doi.org/10.15407/fz57.03.025

Abstract

Activation of large conductance Ca2+-dependent potassium channels (BK channels) influences repolarization of the action potential and the level of the resting potential of detrusor smooth muscle cells (SMC). Overactive bladder syndrome (OBS) is one of the complications of diabetes. Here using whole-cell patch clamp technique we show sizable reduction of depolarization-evoked BK current (T) and decrease in the amplitude and frequency of spontaneous transient outward currents (STOCs) in isolated SMC from detrusor of rats with streptozocin-induced diabetes compared to control animals. Under the diabetes L_ density at step depolarization to +50 mV decreased from control value of 15.0±0.4 pA/pF to 10.0і0.5 pA/pF, whereas the mean values of the STOCs’ frequency and amplitude at holding potential -20 mV were reduced from 12.0±1.5 Hz to 2.4±0.6 Hz and from 0.9±0.1 pA/pF to 0.5±0.1 pA/pF, respectively. Using real time RT-PCR it was found that the expression of mRNA for the BK-channel primary pore-forming KCa 1.1-subunit increases under the diabetes, whilst that for the auxiliary BKC (31-subunit de­creases. It is concluded that the observed changes in the BK-channel currents can enhance excitability of the detrusor SMCs thereby promoting myogenic OBS. However, further studies are needed to determine how the decrease in BK p1 expres­sion under the diabetes impairs functional properties of BK channels and to establish possible changes in calcium signals that modulate channel activation.

Keywords: bladder, detrusor, smooth muscles, diabetes mel-litus, calcium dependent potassium channels, BK-channels

References

  1. Boldyrev OI, Sotkis HV, Kuliieva IeM, Vladymyrova IA, Filippov IB, Skryma R, Prevars'ka N, Shuba IaM. Expression of the cold receptor TRPM8 in the smooth muscles of the seminal ejaculatory ducts in rats. . Fiziol Zh. 2009. 55, N 5. P. 17-27.
  2.  
  3. Brading A.F. Spontaneous activity of lower urinary tract smooth muscles: correlation between ion channels and tissue function . J. Physiol. 2006. 570. P. 13-22. CrossRef PubMed PubMedCentral
  4.  
  5. Christ G.J., Hodges S. Molecular mechanisms of detru­sor and corporal myocyte contraction: identifying tar­gets for pharmacotherapy of bladder and erectile dys­function . Brit. J. Pharmacol. 2006. 147. P. S41-S55. CrossRef PubMed PubMedCentral
  6.  
  7. Heppner T.J., Bonev A.D., Nelson M.T. Ca(2+)-acti-vated K+ channels regulate action potential repola­rization in urinary bladder smooth muscle . Amer. J. Physiol 1997. 273, N 1. P. C110-C117. CrossRef PubMed
  8.  
  9. Hristov K.L., Cui X., Brown S.M., Kellett W.F. Petkov G.V. Stimulation of beta3-adrenoceptors relaxes rat urinary bladder smooth muscle via activation of the large-conductance Ca2+-activated K+ channels . Ibid. 2008. 295,N 5. P. C1344-C1353. CrossRef PubMed PubMedCentral
  10.  
  11. Jaggar J.H., Porter V.A., Lederer W.J., Nelson M.T. Calcium sparks in smooth muscle . Amer. J. Physiol. 2000. 278, N 2. P. C235-C256. CrossRef PubMed
  12.  
  13. McManus O.B., Helms L.M., Pallanck L., Ganetzky B., Swanson R., Leonard R.J. Functional role of the beta subunit of high conductance calcium-activated potassium channels . Neuron. 1995. 14. P. 645-650. CrossRef  
  14. Meredith A.L., Thorneloe K.S., Werner M.E., Nelson M.T. Aldrich W.T. Overactive bladder and incontinence in the absence of the BK large conductance Ca2+-acti-vated K+ channel . J. Biol. Chem. 2004. 279. P. 36746-36752. CrossRef PubMed
  15.  
  16. Orio P., Rojas P., Ferreira G., Latorre R. New dis­guises for an old channel: MaxiK channel beta-sub-units . News Physiol. Sci. 2002. 17. P. 156-161. CrossRef PubMed
  17.  
  18. Petkov G.V., Bonev A.D., Heppner T.J., Brenner R., Aldrich R.W., Nelson M.T. Beta 1-subunit of the Ca2+-activated K+ channel regulates contractile activity of mouse urinary bladder smooth muscle . J. Physiol. 2001. 537. P. 443-452. CrossRef PubMed PubMedCentral
  19.  
  20. Roxburgh C, Cook J., Dublin N. Anticholinergic drugs versus other medications for overactive bladder syn­drome in adults . Cochrane Database Syst. Rev. 2007. 3, N 4. P. CD00319. CrossRef  
  21. Soloviev A., Tishkin S., Ivanova I., Zelensky S., Dosenko V., Kyrychenko S., Moreland R.S. Functional and molecular consequences of ionizing irradiation on large conductance Ca2+-activated K+ channels in rat aortic smooth muscle cells . Life Sci. 2009. 84, N 5-6. P. 164-171. CrossRef PubMed
  22.  
  23. Toro B., Cox N., Wilson R.J., Garrido-Sanabria E., Stefani E., Toro L., Zarei M.M. KCNMB1 regulates surface expression of a voltage and Ca2+-activated K+ channel via endocytic trafficking signals . Neuroscience. 2006. 142, N 3. P. 661-669. CrossRef PubMed

© National Academy of Sciences of Ukraine, Bogomoletz Institute of Physiology, 2014-2019.