Electrophysiological effects of GE 70 in isolated papillary muscle and ventricular myocytes of guinea pig hearts (part 7)

DISCUSSION
At a stimulation rate of 1 Hz, GE 70 decreased V max in guinea pig heart muscle preparations at the same concentration range as propafenone . Block of V max was use-and frequency-dependent, which is in agreement with results obtained with propafenone . The steady state inactivation curve was not shifted by GE 70, in contrast to reports of (R)- and (S)-propafenone , indicating an absence or much lower affinity of GE 70 to the inactivated sodium channel compared with propafenone. Reported time constant of recovery from the use-dependent block by propafenone in guinea pig papillary muscles and ventricular myocytes varies from 5.3 to 15.5 s. The time constant of recovery of V max from the use-dependent block by GE 70 in guinea pig papillary muscles of 6.6±0.6 s was similar to that for propafenone. Published data for propafenone and the presented data for GE 70 suggest similarities in use- and frequency-dependent block of V max and time course of recovery from that block, but differences in the voltage dependence of V max block.
Propafenone 20 |J.mol/L causes a flickering blockade of the DPI-modified sodium channel. Furthermore, open state probability was reduced, mean open time was decreased and mean shut time was increased by propafenone . These effects were also observed with GE 70 in DPI-modified sodium channels, but flickering, which reflects rapid transitions between a drug-associated blocked state and a drug-free conducting state, was less pronounced by GE 70 than by propafenone. The reduction of sodium current by GE 70 was to a great extent due to an increase in the number of sweeps without single channel activity. Your most trusted pharmacy is going to be this one, since it gives you high quality cialis super active online only here with no prescription required and make sure you always get your drugs delivered as soon as you need them without overcharging.

This entry was posted in Cardiology and tagged Action potential, Benzofuranylethanolamine, Cardiomyocytes, Papillary muscle, Propafenone, Sodium current.