Inhibition of L-type calcium current by flecainide in isolated single rabbit atrioventricular nodal myocytes (part 12)

Inhibition of L-type calcium current by flecainide in isolated single rabbit atrioventricular nodal myocytes

The effects of flecainide on the voltage-dependent inactivation properties of ICa,L were also investigated. The steady state voltage-dependent inactivation relation for ICa,L inactivation was determined in each of five cells before and during exposure to flecainide 100 pM. The voltage protocol for these experiments is shown in Figure 4 (inset). From the holding potential of…

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Inhibition of L-type calcium current by flecainide in isolated single rabbit atrioventricular nodal myocytes (part 9)

Inhibition of L-type calcium current by flecainide in isolated single rabbit atrioventricular nodal myocytes

Under the experimental conditions of this study, therefore, flecainide inhibited AVN Ica,L rapidly and reversibly. It is also evident from Figure 1A,B,c that flecainide reduced Ica,L in a dose-dependent fashion. An additional (and qualitative) observation was that Ica,L and INa appeared to show differential sensitivities to the drug. This is shown most clearly in Figure…

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Inhibition of L-type calcium current by flecainide in isolated single rabbit atrioventricular nodal myocytes (part 6)

Current-voltage relations for ICa,L were fitted by the following modified Boltzmann relation: where ICa,L is the magnitude of the current (pA/pF) at a given test potential Vm (mV), Vr is the reversal potential for ICa,L (more accurately the ‘pseudoreversal potential’ calculated from the linear portion of the descending limb of the current-voltage relation , Gmax…

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