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The inhibition of oxidative andnitrosative stresses by ecdysterone as the mechanisms of its cardio- and vasoprotectiveaction at type i diabetes
V.F. Sagach, YU.P. Korkach, A.V. Kotsuruba, O.D. Prysyazhna.
Ін-т фізіології ім. О.О. Богомольця НАН України;Ін-т біохімії ім. О.В. Палладіна НАН України, Київ
Abstract
The effects of whole body ?-irradiation on large conductance
Ca2+ - activated K+ channels (BKCa) function and mRNA ex-
pression in rat thoracic aorta smooth muscle cells (SMCs)
were studied using combined patch-clamp technique in whole-
cell modification and RT-PCR analysis. The stimulation of
control SMCs by increasingly depolarized voltage steps
showed clearly expressed outward K+ currents in control
SMCs. Outward currents in SMCs obtained from irradiated
animals on the 9th and 30th days post-irradiation demon-
strated a significant decrease of K+ current density ampli-
tudes. Paxillin was without effect on irradiated cells on 30th
day post-irradiation indicating the absence of conductance
through BKCa channels. The results of RT-PCR analysis showed
that expression both ?-subunit and ?1-subunit of BKCa
channels appears to be considerably diminished on 30th day
post-irradiation. It is likely that radiation-induced malfunction
functional activity of channels is related with insufficient ex-
pression of BKCa structural elements in SMCs. In conclusion,
the data obtained clearly demonstrate that decreased of the
BKCa channels ?- and ?1-subunit expression in SMCs is a key
factor of abnormality in BKCa channels activity. This abnormal-
ity may contribute to vasorelaxing force depression following
non-fatal whole-body ?-irradiation.
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© National Academy of Sciences of Ukraine, Bogomoletz Institute of Physiology, 2014-2024.
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