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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
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, 2014-2025.
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