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Transmembrane ionic currents in smooth musclecells of rat tail artery
V.L. Reznikov, M.F. Shuba
A.A.Bogomoletz Institute of PhysiologyNational Academy of Science of Ukraine, Kiev
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Abstract
Wholl–cell currents in single smooth muscle cells freshly isolated from the rat tail
artery have been studied using patch-clamp recordings techniques. Outward current
evoked by depolarizing steps from –70mV consisted of the initial fast and subsequent
sustained components. The former was inhibited by 10mM nifedipine and Ca2+-free
solution application whereas the latter decreased by only 16% under these conditions.
Caffeine at 4mM abolished the fast component and only slightly reduced the sustained
component. Both component were inhibited by 1mM TEA+. Adding 10mM EGTA to
the pipette solution abolished the fast outward current. In the presence of 10mM
TEA+ and 4mM 4-AP an inward current was unmasked. These results suggest that the
outward current in these cells is carried mainly via delayed rectifier and Ca 2+-activated
K +-channels. 4-AP inhibited the sustained component and had no effect on the initial
fast outward current, thus A-current is apparently absent.
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© National Academy of Sciences of Ukraine, Bogomoletz Institute of Physiology, 2014-2024.
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